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From: ralf@chpc.org (Ralph Valentino)
Newsgroups: comp.sys.ibm.pc.hardware.video,comp.sys.ibm.pc.hardware.comm,comp.sys.ibm.pc.hardware.storage,comp.sys.ibm.pc.hardware.cd-rom,comp.sys.ibm.pc.hardware.systems,comp.sys.ibm.pc.hardware.networking,comp.sys.ibm.pc.hardware.chips,comp.sys.ibm.pc.hardware.misc,comp.answers,news.answers
Subject: comp.sys.ibm.pc.hardware.* Frequently Asked Questions (FAQ) Part 1/5
Followup-To: comp.sys.ibm.pc.hardware.misc
Date: 12 Aug 1994 02:07:33 -0400
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Summary: This is a monthly posting containing a list of Frequently
	 Asked Questions (and their answers) pertaining to hardware
	 and IBM PC clones.  It should be read by anyone who wishes
	 to post to any group in the comp.sys.ibm.pc.hardware.*
	 hierarchy.
Xref: ankh.iia.org comp.sys.ibm.pc.hardware.video:9599 comp.sys.ibm.pc.hardware.comm:3132 comp.sys.ibm.pc.hardware.storage:7350 comp.sys.ibm.pc.hardware.cd-rom:4232 comp.sys.ibm.pc.hardware.systems:4213 comp.sys.ibm.pc.hardware.networking:2182 comp.sys.ibm.pc.hardware.chips:7711 comp.sys.ibm.pc.hardware.misc:7815 comp.answers:3108 news.answers:9225

Archive-name: pc-hardware-faq/part1
Last-modified: 1994/08/10
Version: 1.7

This FAQ was compiled and written by Willie Lim and Ralph Valentino
with numerous contributions by others.  Acknowledgements are listed at
end of this FAQ.


Copyright notice:

The comp.sys.ibm.pc.hardware.* Frequently Asked Questions is
distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY.  No author or distributor accepts responsibility to anyone
for the consequences of using it or for whether it serves any
particular purpose or works at all, unless he says so in writing.
Refer to the GNU General Public License for full details.

Everyone is granted permission to copy, modify and redistribute this
FAQ, but only under the conditions described in the GNU General Public
License.  Among other things, the copyright notice and this notice
must be preserved on all copies.

Where section authors are noted, the copyright is held by that author.
Where no author is noted, the copyright is held by the FAQ editors
Willie Lim (wlim@lehman.com) and Ralph Valentino (ralf@wpi.wpi.edu).

Changes, additions, comments, suggestions and questions to:
Ralph Valentino	ralf@wpi.edu

Table of Contents:

S) 1.0 Introduction
 Q) 1.1  What does this FAQ cover?
 Q) 1.2  Where can I find the latest copy of this FAQ?
 Q) 1.3  Is it ok to (sell/buy/job-offer/advertise) things here?
 Q) 1.4  +Where should I post?
 Q) 1.5  How come no one answers my questions?
 Q) 1.6  What are the going prices for...?
 Q) 1.7  Who makes/Where can I find [some obscure piece of hardware]?
 Q) 1.8  What is the history of the IBM PC?
S) 2.0 Motherboards
 Q) 2.1  What are the differences between the 80x86 CPUs?
 Q) 2.2  How do I pick the right processor?
 Q) 2.3  What is the difference between the 386SX/386DX and 486SX/486DX?
 Q) 2.4  What is a ZIF socket?
 Q) 2.5  What is over clocking and should I do it?
 Q) 2.6  Which is faster, a DX-50 or DX2-66
 Q) 2.7  *What is the P24T/Overdrive?
 Q) 2.8  What are the differences between the 80x87 co-processors?
 Q) 2.9  Would a math co-processor speed up my machine?
 Q) 2.10  Can I use a x387 with my 486?
 Q) 2.11  Memory terminology, what does it mean?
 Q) 2.12  What happen to my 384k?
 Q) 2.13  How do I tell how big/fast my SIMMs are?
 Q) 2.14  What speed SIMMs do I need?
 Q) 2.15  Will 9 chip and 3 chip SIMMs work together?
 Q) 2.16  +What are "single-sided" and "double-sided" 72-pin SIMMs?
 Q) 2.17  Can I use Mac or PS/2 SIMMs in my PC?
 Q) 2.18  What do wait states and burst rates in my BIOS mean?
 Q) 2.19  Cache terminology, what does it mean?
 Q) 2.20  How do I upgrade the size of my cache?
 Q) 2.21  Do I need to fill the "dirty tag" RAM socket on my motherboard?
 Q) 2.22  How fast do my cache RAMs have to be?
 Q) 2.23  Which is the best cache policy, write-through or "write-back?"
 Q) 2.24  What about an n-way set associative cache, isn't it better?
 Q) 2.25  Which is better, ISA/EISA/VLB/PCI/etc?
 Q) 2.26  *What are the (dis)advantages of ISA/VLB/EISA SCSI?
 Q) 2.27  Will an ISA card work in an MCA (PS/2) machine?
 Q) 2.28  *What does the "chip set" do?
 Q) 2.29  How do I enter the CMOS configuration menu?
 Q) 2.30  What is bus mastering and how do I know if I have it?
 Q) 2.31  Can I put an ISA cards in EISA or VLB slots?
 Q) 2.32  How should I configure ISA/VLB cards in the EISA config utility?
 Q) 2.33  What is the difference between EISA Standard and Enhanced modes?
 Q) 2.34  Is there any point in putting more than 16M in an ISA machine?
 Q) 2.35  What disadvantages are there to the HiNT EISA chip set?
 Q) 2.36  *Should I change the ISA bus speed?
 Q) 2.37  +Why is my PC's clock so inaccurate?
 Q) 2.38  +How can I automatically set my PC's clock to the correct time?
 Q) 2.39  Can I use IRQ2 or is it special?
 Q) 2.40  Where do all the IRQ's go?
S) 3.0 IO controllers/interfaces
 Q) 3.1  *How do IDE/MFM/RLL/ESDI/SCSI interfaces work?
 Q) 3.2  *How can I tell if I have MFM/RLL/ESDI/IDE/SCSI?
 Q) 3.3  Do caching controllers really help?
 Q) 3.4  Do IDE controllers use DMA?
 Q) 3.5  Why won't my two IDE drives work together?
 Q) 3.6  Which is better, VLB or ISA IDE?
 Q) 3.7  How do I install a second controller?
 Q) 3.8  Which is better, SCSI or IDE?
 Q) 3.9  Can MFM/RLL/ESDI/IDE and SCSI coexist?
 Q) 3.10  What's the difference between SCSI and SCSI-2? Are they compatible?
 Q) 3.11  Can I share SCSI devices between computers?
 Q) 3.12  What is Thermal Recalibration?
 Q) 3.13  How do I swap A: and B:
 Q) 3.14  My floppy drive doesn't work and the light remains on, why?
 Q) 3.15  What is a 16550 and do I need one?
 Q) 3.16  *Are there any >4 serial port cards?
 Q) 3.17  Should I buy an internal or external modem?
 Q) 3.18  What do all of the modem terms mean?
 Q) 3.19  What kinds of sound cards are avalable?
 Q) 3.20  Where can I find EISA/VLB sound and IO cards?
 Q) 3.21  How does the keyboard interface work?
 Q) 3.22  Can I fake a keyboard so my computer will boot without it?
S) 4.0 Storage/Retrieval Devices
 Q) 4.1  Why do I lose x Meg on my hard drive?
 Q) 4.2  *Should I get an IDE/floppy/SCSI/parallel port tape drive?
 Q) 4.3  I have two floppies. Can I add a floppy based tape drive?
 Q) 4.4  How fast is a tape drive? Will a dedicated controller improve this?
 Q) 4.5  What is QIC80, QIC40?
 Q) 4.6  How come I can't fit as much stuff on my tape drive as they claim?
 Q) 4.7  Are Colorado/Conner/Archive/... tapes compatible with each other?
 Q) 4.8  How does the drive/software know how long the tape is?
 Q) 4.9  What are all those QICs?
 Q) 4.10  Which QICs are read/write compatible?
 Q) 4.11  What is the CMOS/jumper setting for my hard drive?
S) 5.0 Video
 Q) 5.1  Can I use two video cards in the same system?
 Q) 5.2  *What kinds of monitors are available?
 Q) 5.3  *Can I get an RGB monitor to work with my PC?
 Q) 5.4  *How can I hook more than one monitor to my video card?
 Q) 5.5  *Which video card is best for DOS/Windows/X11/OS2?
 Q) 5.6  *What is the black horizontal line on my monitor?
S) 6.0 Systems
 Q) 6.1  *What should I upgrade first?
 Q) 6.2  Do I need a CPU fan / heat sink
 Q) 6.3  What does the turbo switch do?
 Q) 6.4  How does the front panel LED display measure the system's speed?
 Q) 6.5  Should I turn my computer/monitor off?
 Q) 6.6  Are there any manufacturers/distributers who read the net?
S) 7.0 Diagnostics
 Q) 7.1  What do the POST beeps mean?
 Q) 7.2  What do the POST codes mean?
 Q) 7.3  *I think my cache is bad. What's a good diagnostic?
S) 8.0 Misc
 Q) 8.1  What is the pin out for ...?
 Q) 8.2  *Where are benchmark programs located. What do they mean?
 Q) 8.3  What is Plug and Play?
 Q) 8.4  What size should I set my DOS partitions to be?
 Q) 8.5  Why won't my system boot from the hard drive?
 Q) 8.6  How do I clean my computer?
 Q) 8.7  *What OS's are available for the PC? Which are free?
 Q) 8.8  *How can I transfer files between my PC and a Unix system?
 Q) 8.9  What tape backup software is available?
 Q) 8.10  Why doesn't my new device work as fast as it should?
 Q) 8.11  My drive lists a MTBF of 300,000 hours. Will it really last 34 years?
 Q) 8.12  How do I find pin 1 on my chip/card/cable/connector?
 Q) 8.13  I've run out of power connectors, what can I do?
S) 9.0 References
 Q) 9.1  What other FAQ's are out there?
 Q) 9.2  What do the industry acronyms stand for?
 Q) 9.3  Where can I get the ISA/EISA/VLB/PCI/etc specs?
 Q) 9.4  What books are available for the PC architecture?
 Q) 9.5  What books are available on network programming?
 Q) 9.6  +What's the phone number for...
S) 10.0 Acknowledgments

* = incomplete
+ = new or significant changes since last post

S) 1.0 Introduction

Q) 1.1  What does this FAQ cover?

This FAQ covers Frequently Asked Questions from all groups in the
comp.sys.ibm.pc.hardware.* hierarchy.  Software topics are only
included if they are directly related to hardware or hardware
interfacing.

Q) 1.2  Where can I find the latest copy of this FAQ?

If you haven't done so, new users on the net should read
news.announce.newusers. In particular, the following posts are a good
idea:
	A Primer on How to Work With The Usenet Community
	Answers to Frequently Asked Questions About Usenet
	Hints on Writing Style for Usenet
	Introduction to The *.answers Groups

This FAQ is currently posted to news.answers, comp.answers,
comp.sys.ibm.pc.hardware.cd-rom, comp.sys.ibm.pc.hardware.chips,
comp.sys.ibm.pc.hardware.comm, comp.sys.ibm.pc.hardware.misc,
comp.sys.ibm.pc.hardware.networking, comp.sys.ibm.pc.hardware.storage,
comp.sys.ibm.pc.hardware.systems, and comp.sys.ibm.pc.hardware.video.
All posts to news.answers are archived and are available via anonymous
FTP, uucp and e-mail from the following locations:

FTP:
	FTP is a way of copying file between networked computers. If
	you need help in using or getting started with FTP, send
	e-mail to mail-server@rtfm.mit.edu with
		send usenet/news.answers/ftp-list/faq
	as the body of the message.

	location:  rtfm.mit.edu [18.70.0.224]
	directory: /pub/usenet/news.answers/pc-hardware-faq
	filenames: part1 to part5

	location:  ftp.uu.net [137.39.1.9]
	directory: /archive/usenet/news.answers/pc-hardware-faq
	filenames: part1.Z to part5.Z [use uncompress]

	location:  nic.switch.ch [130.59.1.40]
	directory: info_service/Usenet/periodic-postings
	filenames: [Check info_service/Usenet/00index]


UUCP:
	location:  uunet!/archive/usenet/news.answers/pc-hardware-faq/
	filenames: part1.Z to part5.Z

E-mail:
	Send email to mail-server@rtfm.mit.edu containing these lines:
	send usenet/news.answers/pc-hardware-faq/part1
        ...
	send usenet/news.answers/pc-hardware-faq/part5

You can find a dozen or more sites in the US, Europe and Japan that
store the FAQ and archives for this various newsgroups by using the
Internet search programs, Archie or Wais.

Q) 1.3  Is it ok to (sell/buy/job-offer/advertise) things here?

No, none of the above fit within the charter of the
comp.sys.ibm.pc.hardware.* hierarchy, therefore such posts are
considered unacceptable.  For buying/selling things, use groups with
the words 'wanted' or 'forsale', and for job offers, use groups with
the words 'jobs'.  All of these can be found in the misc.* hierarchy.
For commercial advertisements, use only the biz.* hierarchy as per the
guidelines of USENET.  (refer to the news.* groups for more
information).

Q) 1.4  +Where should I post?

[From: grohol@alpha.acast.nova.edu (John M. Grohol)]

PC-Clone Hardware Newsgroup Pointer                   By: John M. Grohol

This Pointer will help you find the information you need and get your
questions answered much quicker than if you were to simply crosspost to
every hardware newsgroup in existence. It is provided as a public service.
Post your article in the most appropriate newsgroup according to its topic.
Please do not post your hardware questions to software newsgroups,
and vice-a-versa. "For Sale" articles are never appropriate to
either the hardware or software newsgroups.

Comments & suggestions are always welcome! 

Question on...                       Post to...
-----------------------------------  ----------------------------------
Networking/networks                  comp.sys.novell
                                     comp.dcom.lans.* (where * equals:
                                     ethernet; fddi; misc; token-ring)
				     comp.protocols.tcp-ip.ibmpc
			 	     comp.os.os2.networking.misc
                                     comp.os.os2.networking.tcpip
PC Networking hardware/cards/cables  comp.sys.ibm.pc.hardware.networking
-----------------------------------  ----------------------------------
Servers                              comp.dcom.servers
Modems                               comp.dcom.modems
Printers                             comp.periphs.printers
SCSI devices                         comp.periphs.scsi
Other peripherals                    comp.periphs
PCMCIA devices                       alt.periphs.pcmcia
Gateway 2000 users                   alt.sys.pc-clone.gateway2000
-----------------------------------  ----------------------------------
Technical topics on PC soundcards    comp.sys.ibm.pc.soundcard.tech
Advocacy for a particular soundcard  comp.sys.ibm.pc.soundcard.advocacy
Using soundcards with games          comp.sys.ibm.pc.soundcard.games
Music & sound using soundcards       comp.sys.ibm.pc.soundcard.music
Soundcards in general                comp.sys.ibm.pc.soundcard.misc
-----------------------------------  ----------------------------------
Non-commercial sale of hardware      misc.forsale.computers.pc-clone
Commercial sale of hardware          biz.comp.hardware
-----------------------------------  ----------------------------------
Monitors/video cards                 comp.sys.ibm.pc.hardware.video
Modems/fax cards/communication       comp.sys.ibm.pc.hardware.comm
Hard/floppy/tape drives & media      comp.sys.ibm.pc.hardware.storage 
CD-ROM drives & interfaces           comp.sys.ibm.pc.hardware.cd-rom
Computer vendors & specific systems  comp.sys.ibm.pc.hardware.systems
System chips/RAM chips/cache         comp.sys.ibm.pc.hardware.chips
-----------------------------------  ----------------------------------
Other hardware questions             comp.sys.ibm.pc.hardware.misc
-----------------------------------  ----------------------------------

This Pointer may be duplicated or retransmitted in any form as
long as it remains fully intact. Copyright retained by author.

Send comments/questions/suggestions regarding this newsgroup Pointer
to John M. Grohol (grohol@alpha.acast.nova.edu).


Q) 1.5  How come no one answers my questions?

If you don't give enough information when asking your question, then
people will not be able to answer it.  If you're not willing to take
the time to look up the necessary information, then why should you
expect people to take the time to answer your question?  For instance,
if you're asking a question about SCSI, it is very important to know
what type of SCSI host adapter (controller) you have.  Some other
important things to mention are which device drivers/tsr's you are
loading, what other similar devices you have in your system, and
exactly what in your setup has changed since it last worked.

Q) 1.6  What are the going prices for...?

If you're looking for new equipment, pick up a copy of Computer
Shopper.  This is the "bible" for buying new equipment.  Skim through
it for the best prices and give these distributers a call.  In most
cases, the advertisements must be placed months in advance; the actual
price may be even lower than the advertised price!  Two other things
to note are the warranty, return policy and location of the company
(companies within the same state as you may be required to add extra
sales taxes).

If you're looking for the expected price of used equipment, then scan
the newsgroup misc.forsale.computers.pc-clone for similar items.  This
will give you the best idea as what to expect.  Don't make assumptions
that the price of used equipment will follow the market trends of new
equipment.  For instance, when new memory prices nearly doubled, the
used prices were barely effected.

Q) 1.7  Who makes/Where can I find [some obscure piece of hardware]?

[From: uwvax!astroatc!nicmad!madnix!zaphod (Ron Bean)]

You can ask on the net, but you'll get a better response if you do
some investigating on your own first. Try calling vendors who
advertise similar or related hardware, they often have things that
aren't in the ads. Vendors who specialize in parts rather than
complete systems are a good bet. You can also ask local dealers to
check their wholesale sources.


Q) 1.8  What is the history of the IBM PC?

[From:]

Around 1978 and '79, the market served by IBM's Data Entry Systems
division began to change.  Instead of terminals and minicomputers or
mainframes, customers began demanding autonomous, low cost,
single-user computers with minimal compute power or connectivity, but
compliance to standards like the ASCII alphabet and the BASIC
programming language.  The closest product in IBM's line was the 5110,
a closed, BASIC-in-ROM machine with a tiny built-in character display.
The 5110 was uncompetitive, and IBM started losing bids from key
customers, mostly government agencies.

Data Entry commissioned a consulting firm (Boca Associates?) to design
a stop-gap machine to fill what was perceived within IBM as a
short-lived, specialized niche.  It was intended that the stop-gap
machine would only be offered for a couple of years until it would be
replaced in "The Product Line" by an internal IBM design.  Some IBM
executives believed the single-user desktop system was a fad which
would die out when the shortcomings of such systems became
appreciated.

The motherboard design was based very closely on a single-board
computer described in a 1978 (?) Intel application note.  (Anybody got
an original copy of this collector's item?  Among other things, Intel
argues that 640KB is more memory than single-user applications will
ever need, because of the efficiency of segmented memory
"management"!)  The expansion slot "bus" is based on an Intel bus
called Multibus 1, which Intel introduced in its microprocessor
software development equipment in the mid '70s.  The Monochrome and
Color Graphics Display Adapters are based on application notes for the
Motorola 6845 video controller chip, except that the strangely
interlaced pixel addresses in the CGA appears to have been extremely
short sighted.  The "event driven" keyboard is an original design, but
the concept is from the Xerox Alto and Star graphics workstations.
The keyboard noise and "feel" are intended to emulate those of the IBM
Selectric typewriter.  The Cassette Interface design is original, but
similar in concept to the one on the Radio Shack TRS-80.

Data Entry Division approached Digital Research Inc. to offer its
popular CP/M-86 operating system on the machine, but DRI rebuffed
them.  IBM's second choice was BASIC-in-ROM vendor Microsoft, which
had no OS product at the time but quickly purchased a crude disk
operating system called 86-DOS from Seattle Computer Products to offer
it to IBM.  Its command interpreter was an imitation of Unix' Bourne
Shell, with the special characters changed to avoid infringing AT&T's
rights.

Data Entry Division began bidding this system in various State
procurements, without any plan to offer it to the public.

It became obvious that the Cassette Interface and optional 360KB
Flexible Disk Drive were inadequate.  The Cassette Interface was
dropped, and an optional Fixed Disk Drive offered on a revised model
known as the IBM Personal Computer XT.  (A fixed, or "hard" disk had
been offered on the PC by special order, with a Xebec controller, but
few were sold.)  The disk controller was designed around the Western
Digital 1010 chip, and its design is taken directly from a WD
application note.

The XT succeeded beyond all expectations.  IBM offered the system to
the public after it became clear that no other division was going to
come up with anything timely.  IBM published complete schematics and
ROM listings, encouraging clones.

In 1984, IBM introduced an upwardly compatible model based on the
Intel 80286.  The expansion slot "bus" was extended to 16-bit data
path width the same way Intel had extended Multibus: by adding data
and address bits, a signal for boards to announce their capability to
perform 16-bit transfers, and byte swapping on the motherboard to
support the 8-bit boards.

S) 2.0 Motherboards

Q) 2.1  What are the differences between the 80x86 CPUs?

This section is posted separately as the "Personal Computer Chiplist"
and archived along side this FAQ.  Refer to section one for
instructions on retrieving this file.

Subject: Personal Computer CHIPLIST *.* (Part * / *)
From: offerman@einstein.et.tudelft.nl (A. Offerman)
Newsgroups: comp.sys.ibm.pc.hardware.chips
Summary: This list contains the various CPU's and NPX's and their features,
         used in the IBM PC, IBM PC/XT, IBM PC/AT, IBM PS/2 and compatbles,
         and the differences between them.
Archive-name: pc-hardware-faq/chiplist/part*

Q) 2.2  How do I pick the right processor?

[From: jabram@ichips.intel.com (Jeff Abramson)]

This is a hard question.  You have tradeoffs between price,
performance, compatibility, upgradebility, and power consumption.
As a desktop unit owner, you probably have less concerns about
power, but as a laptop owner, this is very important.

The frequency of the CPU defines how fast its internal clock runs.
This defines how fast instructions are executed.  In many ways, this
is meaningless, because a RISC machine (MIPS) running at 100MHz may
in reality be slower than a 50Mhz i486 because a RISC system must
execute more instructions to perform the same function (in some
cases).  Even when comparing processors in the same family, this
info can be misleading.  For example, an Intel486-25 is faster than
an AMD386-40, since the 486 has microarchitectural advancements over
the 386.  The same can be said for the Pentium, where a 66Mhz
Pentium is twice as fast as a 66MHz 486.

For compatibility, keep in mind that the Intel parts are the basis
for all of these processors.  Therefore you always run the risk that
an imitator's part may not be compatible.  AMD chips are compatible
because they are copied.  For some of you, these factors may be
important.

As far as upgradability goes, this depends on both your motherboard
and the processor.  If you purchase a 486DX, then you can upgrade to
a DX2 and double your internal clock simply by buying an overdrive
chip if your motherboard has the ZIF socket.  If it doesn't then you
can replace the CPU with a DX2.  Many new 486 motherboards contain
overdrive sockets for the not-yet-released Pentium chip that is pin
compatible.

Q) 2.3  What is the difference between the 386SX/386DX and 486SX/486DX?

[From: jabram@ichips.intel.com (Jeff Abramson)]

The Intel386DX contains full 32 bit buses for external data,
internal data, and address.  The Intel386SX contains a smaller 16
bit external data bus, and a smaller 24 bit address bus.

The Intel486DX contains a floating point unit, the Intel486SX does
not.  A common rumor is that the 486SX is simply a DX part that has
a failure in the floating point unit, so it has been disabled and
the part has been produces as an SX.  This was true for early
production parts and samples, but not for the mass produces SX parts
that we see today.  

Q) 2.4  What is a ZIF socket?

[From: jabram@ichips.intel.com (Jeff Abramson)]

ZIF stands for Zero Insertion Force, and describes a socket on your
motherboard that supports an upgrade processor (overdrive
processor).  In general, an overdrive upgrade works in conjunction
with your original processor so you cannot remove the original
processor after upgrade.  NOTE: Some motherboards do not have a ZIF
socket so you must replace the existing processor to upgrade.

Q) 2.5  What is over clocking and should I do it?

[From: jabram@ichips.intel.com (Jeff Abramson)]

Overclocking is a term generally used to describe how you have
increased the clock frequency on your board to run your system at a
higher speed.  For example, if you plug a 25MHz i486 into a board
that is configured to run a 33MHz i486, then you are overclocking
your CPU.  Most boards allow you to configure your clocking via
jumpers, and others require a new clock oscillator.

Although users have had success with overclocking, it is a dangerous
practice for two reasons.  First, the chip has been designed to meet
a certain speed.  Therefore, some circuits do not have the margin to
operate at a higher frequency.  The chips coming from a wafer have
various speed specs (statistical distribution), so you may be lucky
and own a CPU that has the circuit margins you need to overclock.
But you don't know - and if you overclock, you may get data failure.
The data failure may be reproducable - and therefore avoidable, but
most likely not.

Second, you have reliability concerns when overclocking.
Overclocking means faster frequency, which means more current and
power.  This can lead to real failures in your CPU.
Electromigration is one such failure where metal lines in your CPU
will actually break or connect if they get too much current.  This
is irreversable, and most likely not covered under warranty.

So when can you overclock?  Really only if you don't care about
burning out your CPU and you don't care if you get wrong data every
now and then.  If you own a machine and you use it just for games,
then overclocking may be something to try - and you simply upgrade
to a new CPU when you burn out the current one.  Otherwise, it's not
worth the small performance gain.

Q) 2.6  Which is faster, a DX-50 or DX2-66

The two processors are relatively close for overall usage.  The DX-50
has more I/O bandwidth and the DX2-66 has more computational power.

Q) 2.7  *What is the P24T/Overdrive?
Q) 2.8  What are the differences between the 80x87 co-processors?

See reference in: "What are the differences between the 80x86 CPUs?"

Q) 2.9  Would a math co-processor speed up my machine?

[From: jruchak@mtmis1.mis.semi.harris.com (John Anthony Ruchak)]

If you do a lot of number-crunching with CAD/CAM applications,
spreadsheets, and the like, a math co-processor is likely to increase
performance.  If on the other hand, your primary work is word
processing, a math co-processor will have barely any effect at all.
Also, a math co-processor will not provide any benefit if your CPU
already has one built-in (486/586-DX chips).  In addition, a math
co-processor is not likely to improve the over-all performance of
Microsoft Windows, except when you are running the afore-mentioned
number-crunching programs.

Q) 2.10  Can I use a x387 with my 486?

[From: Shaun Burnett (burnesa@cat.com)]

No, they are not pin compatible.  The 486DX and above contain an
on-chip floating point unit. Therefore, a 387 (SX or DX) math
coprocessor is not needed.  All software written for a 387 coprocessor
will run on your 486.
 
If you want a math coprocessor for a 486SX, you need to purchase the
487SX or a 486 Overdrive processor.
 
While we're talking about math coprocessors, I'll make a brief note
about the Weitek.  Some motherboards may have a socket for a Weitek
math coprocessor.  These coprocessors are not compatible with the
Intel 387 math coprocessor and should only be used if your software
requires it.  The Weitek 3167 replaced the Weitek 1167 and is for the
386 while the Weitek 4167 is for a 486.

Q) 2.11  Memory terminology, what does it mean?

[From: cls@truffula.sj.ca.us (Cameron L. Spitzer)]

Read/write memory in computers is implemented using Random Access Memory
chips (RAMs).  RAMs are also used to store the displayed image in a video
board, to buffer frames in a network controller or sectors in a disk
controller, etc.  RAMs are sold by their size (in bits), word width (how
many bits can you access in one cycle), and access time (how fast you
can read a location), among other characteristics.


SRAMs and DRAMs
---------------
RAMs can be classified into two types: "static" and "dynamic."

In a static RAM, each bit is represented by the state of a circuit
with two stable states.  Such a "bistable" circuit can be built with four
transistors (for maximum density) or six (for highest speed and lowest
power).  Static RAMs (SRAMs) are available in many configurations.
(Almost) all SRAMs have one pin per address line, and all of them
are able to store data for as long as power is applied, without any
external circuit activity.

In a dynamic RAM (DRAM), each bit is represented by the charge on a
*very* small (30-50 femptofarads) capacitor, which is built into a
single, specialized transistor.  DRAM storage cells take only about
a quarter of the silicon area that SRAM cells take, and silicon
area translates into cost.
The cells in a DRAM are organized into rows and columns.  To access
a bit, you first select its row, and then you select its column.
Unfortunately, the charge leaks off the capacitor over time,
so each cell must be periodically "refreshed" by reading it and
writing it back.  This happens automatically whenever a row is accessed.
After you're finished accessing a row, you have to give the DRAM time
to copy the row of bits back to the cells: the "precharge" time.

Because the row and column addresses are not needed at the same
time, they share the same pins.  This makes the DRAM package smaller
and cheaper, but it makes the problem of distributing the signals
in the memory array difficult, because the timing becomes so
critical.  Signal integrity in the memory array is one of the
things that differentiate a lousy motherboard from a high quality
one.

SIMMs and SIPPs
---------------
Through the 1970s, RAMs were shipped in tubes, and the board makers
soldered them into boards or plugged them into sockets on boards.
This became a problem when end-users started installing their own
RAMs, because the leads ("pins") were too delicate.  Also, the
individual dual in-line package (DIP) sockets took up too much board
area.
In the early 1980s, DRAM manufacturers began offering DRAMs on tiny
circuit boards which snap into special sockets, and by the late '80s
these "single in-line memory modules" (SIMMs) had become the most popular
DRAM packaging.  Board vendors who didn't trust the new SIMM sockets
used modules with pins: single inline pinned packages (SIPPs),
which plug into sockets with more traditional pin receptacles.

PC-compatibles store each byte in main memory with an associated
check bit, or "parity bit."  That's why you add memory in multiples
of nine bits.  The most common SIMMs present nine bits of data at
each cycle (we say they're "nine bits wide") and have thirty contact
pads, or "leads."  (The leads are commonly called "pins" in the trade,
although "pads" is a more appropriate term.  SIMMs don't *have* pins!)

At the high end of the PC market, "36 bit wide" SIMMs with 72 pads
are gaining popularity.  Because of their wide data path, 36-bit SIMMs
give the motherboard designer more configuration options (you can
upgrade in smaller chunks) and allow bandwidth-enhancing tricks
(i.e. interleaving) which were once reserved for larger machines.
Another advantage of 72-lead SIMMs is that four of the leads are used
to tell the motherboard how fast the RAMs are, so it can configure
itself automatically.  (I do not know whether the current crop of
motherboards takes advantage of this feature.)

"3-chip" and "9-chip" SIMMs

In 1988 and '89, when 1 megabit (1Mb) DRAMs were new, manufacturers
had to pack nine RAMs onto a 1 megabyte (1MB) SIMM.  Now (1993) 4Mb DRAMs
are the most cost-effective size.  So a 1MB SIMM can be built with
two 4Mb DRAMs (configured 1M x4) plus a 1Mb (x1) for the check-bit.

VRAMs
-----
In graphics-capable video boards, the displayed image is almost
always stored in DRAMs.  Access to this data must be shared between
the hardware which continuously copies it to the display device (this
process is called "display refresh" or "video refresh") and
the CPU.  Most boards do it by time-sharing ordinary, single-port
DRAMs.  But the faster, more expensive boards use specialized DRAMs
which are equipped with a second data port whose function is tailored
to the display refresh operation.  These "Video DRAMs" (VRAMs) 
have a few extra pins and command a price premium.  They nearly double
the bandwidth available to the CPU or graphics engine.

(As far as I know, the first dual-ported DRAMs were built by Four-
Phase Systems Inc., in 1970, for use in their "IV-70" minicomputers, which
had integrated video.  The major DRAM vendors started offering VRAMs
in about 1983 [Texas Instruments was first], and workstation vendors
snapped them up.  They made it to the PC trade in the late '80s.)

Speed
-----
DRAMs are characterized by the time it takes to read a word,
measured from the row address becoming valid to the data coming out.
This parameter is called Row Access Time, or tRAC.  There are many
other timing parameters to a DRAM, but they scale with tRAC
remarkably well.  tRAC is measured in nanoseconds (ns).
A nanosecond is one billionth (10 e-9) of a second.

It's so difficult to control the semiconductor fabrication processes,
that the parts don't all come out the same.  Instead, their performance
varies widely, depending on many factors.  A RAM design which would
yield 50 ns tRAC parts if the fab were always tuned perfectly, instead 
yields a distribution of parts from 80 to 50.  When the plant is new,
it may turn out mostly nominal 70 ns parts, which may actually deliver 
tRAC between 60.1 ns and 70.0 ns, at 70 or 85 degrees Celcius and
4.5 volts power supply.  As it gets tuned up, it may turn out mostly 60 
ns parts and a few 50s and 70s.  When it wears out it may get less 
accurate and start yielding more 70s again.

RAM vendors have to test each part off the line to see how fast it is.  
An accurate, at-speed DRAM tester can cost several million dollars, and 
testing can be a quarter of the cost of the parts.  The finished parts 
are not marked until they are tested and their speed is known.


Q) 2.12  What happen to my 384k?

The memory between 640k and 1Meg is used for the BIOS, the video
aperture, and a number of other things.  With the proper memory
manager, DOS can take advantage of it.  Many systems, however, won't
identify its existence on boot.  This does not mean it isn't there.

Q) 2.13  How do I tell how big/fast my SIMMs are?

Individual DRAMs are marked with their speed after they are tested.
The mark is usually a suffix to the part number, representing tens of
nanoseconds.  Thus, a 511024-7 on a SIMM is very likely a 70 ns DRAM.
(vendor numbering scheme table to be added)

Q) 2.14  What speed SIMMs do I need?

[From: cls@truffula.sj.ca.us (Cameron L. Spitzer)]

There is no reliable formula for deriving the required RAM speed from
the clock rate or wait states on the motherboard.  Do not buy a
motherboard that doesn't come with a manual that clearly specifies
what speed SIMMs are required at each clock rate.  You can always
substitute *faster* SIMMs for the ones that were called out in the
manual.  If you are investing in a substantial quantity of RAM,
consider buying faster than you need on the chance you can keep it
when you get a faster CPU.

That said, most 25 MHz and slower motherboards work fine with 80 ns
parts, most 33 MHz boards and some 40 MHz boards were designed for
70 ns parts, and some 40 MHz boards and everything faster require
60 ns or faster.  Some motherboards allow programming extra wait states
to allow for slower parts, but some of these designs do not really relax
all the critical timing requirements by doing that.  It's much
safer to use DRAMs that are fast enough for the no-wait or one-wait
cycles at the top end of the motherboard's capabilities.

Q) 2.15  Will 9 chip and 3 chip SIMMs work together?

[From: cls@truffula.sj.ca.us (Cameron L. Spitzer)]

Almost always.  But there are exceptions.

1.  Some motherboards do not supply enough refresh address bits for a
4Mb x1 or a 1Mb x4 DRAM.  These old motherboards will not work with 4
MB 9-chip SIMMs or 1 MB 3-chip SIMMS.

2.  Some EL CHEAPO motherboards do not have proper terminations on the
lines which drive the DRAM array.  These boards may show only marginal
compatibility with various SIMMs, not working with all prefectly good
SIMMs you try, favoring SIMMs with parameters skewed towards one end
or another of the allowed ranges.  In some cases, most of the SIMMs
you happen to try might be 9-chip modules, and in other cases they
might be 3-chip modules.  A random selection of a dozen SIMMs might
lead you to conclude the motherboard doesn't "work" with 3-chip
modules, or with a "mixture" of 3-chip and 9-chip modules.

You might find the real solution is to use SIMMs one speed faster
than the manual calls for, because the particular motherboard design
just cuts too many things too close.

Q) 2.16  +What are "single-sided" and "double-sided" 72-pin SIMMs?

[From: uwvax!astroatc!nicmad!madnix!zaphod (Ron Bean)]
 
   All 72-pin SIMMs are 32 bits wide (36 with parity), but
double-sided SIMMs have four RAS (Row Address Strobe) lines instead of
two. This can be thought of as two single-sided SIMMs in parallel,
with all the other pins wired together (it has nothing to do with
whether there are chips on both sides of the board).
 
   Some motherboards can take four SIMMs if they're single-sided, but
only two if they're double-sided. Others can take four of either
type. Usually, 1Mb, 4Mb, and 16Mb 72-pin SIMMs are single-sided, and
2Mb, 8Mb, and 32Mb SIMMs are double-sided. In either case, Pentiums
require them in pairs to get 64-bit-wide memory (plus 8 bits for
parity).


Q) 2.17  Can I use Mac or PS/2 SIMMs in my PC?

Yes, just about all SIMMs are compatible, be they from another
personal computer, a mainframe, or even a laser printer, though are a
few some odd systems out there.  There are three significant issues:
speed, parity and number of pins (data width).  Speed is obvious,
check the rating, ie: 70ns, to make sure they meet the minimum
requirements of your system.  Parity either exists or doesn't exist
and can be identified by an extra bit per byte, ie: 9 bits or 36 bits.
If your system does not require parity, you can still use SIMMs with
parity.  If, however, your system does require parity, you can't use
SIMMs without parity.  For this case, many PC's have an option to
disable the parity requirement via a jumper or BIOS setting; refer to
your motherboard manual.  The final issue is the number of pins on the
SIMM; the two most common are 30 pins (8 or 9 bit SIMMs) and 72 pins
(32 or 36 bit SIMMs); the second is physically larger thus the one can
not be used in the other.  A few motherboards have both types of
sockets.

Q) 2.18  What do wait states and burst rates in my BIOS mean?

[From: cls@truffula.sj.ca.us (Cameron L. Spitzer)]

Modern motherboards are equipped with variable clocks and features
for tuning board performance at each speed.  The BIOS knows how to
program the register bits which control these options.

1.  Wait states may be adjustable to allow for slower DRAMs or
cache RAMs.  If you don't have a motherboard manual, or it doesn't
say, then you will just have to experiment.
2.  Sometimes a wait or two on a write is required with write-through
cache.  The programming allows for slower DRAMs.  The extra wait
state may cost you enough time that you would do better running at a
slower clock rate where the wait state is not required.
3.  Burst rates refer to the number of wait states inserted for
each longword access in the cache fill cycle.

Bob Nichols (rnichols@ihlpm.ih.att.com) adds:
These numbers refer to the number of clock cycles for each access of a
"burst mode" memory read.  The fastest a 486 can access memory is 2 clock
cycles for the first word and 1 cycle for each subsequent word, so
"2-1-1-1" corresponds to "zero wait states."  Anything else is slower.

How fast you can go depends on the external clock speed of your CPU, the
access time of your cache SRAMs, and the design of the cache controller.
It can also be affected by the amount of cache equipped, since "x-1-1-1"
is generally dependent on having 2 banks of cache SRAMs so that the
accesses can be interleaved.  With a 50MHz bus (486DX-50), few
motherboards can manage "2-1-1-1" no matter how fast the SRAMs are.  At
33MHz or less (486DX-33, 486DX2-66), many motherboards can achieve
"2-1-1-1" if the cache SRAMs are fast enough and there are 2 banks
equipped (cache sizes of 64KB or 256KB, typically).

Q) 2.19  Cache terminology, what does it mean?

[From: cls@truffula.sj.ca.us (Cameron L. Spitzer)]

Why cache improves performance
------------------------------
Today's microprocessors ("uPs") need a faster memory than can be made
with economical DRAMs.  So we provide a fast SRAM buffer
between the DRAM and the uP.  The most popular way to set it up is
by constructing a "direct mapped cache," which is the only setup
I'll describe here.


Generic motherboard cache architecture
--------------------------------------
The direct mapped cache has three big features:
1. a "data store" made with fast SRAMs,
2  a "tag store" made with even faster SRAMs, and
3. a comparator.

The data store is the chunk of RAM you see in the motherboard price
lists.  It holds "blocks" or "lines" of data recently used by the CPU.
Lines are almost always 16 bytes.  The address feeding the cache is
simply the least significant part of the address feeding main memory.
Each memory location can be cached in only one location in the data
store.

There are two "policies" for managing the data store.  Under the
"write-back" (or "copy-back") policy, the master copy of the data is
in cache, and main memory locations may be "stale" at times.  Under
"write-through", writes go immediately to main memory as well as to
cache and memory is never "stale."

The tag store mantains one "word" of information about each line of
data in the data store.
In a "write-back" or "copy-back" cache, the tag word contains two items:
1.  the part of the main memory address that was *not*
    fed to the data store, and
2.  a "dirty" bit.

A write-through cache doesn't need a dirty bit.  The tag store is
addressed with the most significant address bits that are being fed to
the data store.  The tag is only concerned with the address bits that
are used to select a line.  With a 16 byte line, address bits 0
through 3 are irrelevant to the tag.

An example: The motherboard has 32 MB main memory and 256 KB cache.
To specify a byte in main memory, 25 bits of address are required: A0
through A24.  To specify a byte in data store, 18 bits (A0 through
A17) are required.  Lines in cache are 16 bytes on 16 byte boundaries,
so only A3 through A17 are required to specify a line.  The tag word
for this system would represent A18 through A24 (plus dirty bit).  The
tag store in this system would be addressed by A3 through A17,
therefore the tag store would require 16 K tag words seven bits wide.
The dirty bit is written at different times than the rest of the tag,
so it might be housed separately, and this tag store might be built in
three 16K x4 SRAMs.

What happens when it runs
-------------------------
Each motherboard memory cycle begins when the uP puts out a memory
address.  The data store begins fetching, and simultaneously the
tag begins fetching.  When the tag word is ready, the Comparator
compares the tag word to the current address.

If they match, a cache hit is declared and the uP reads or writes
the data store location.  If the hit is a write, the copy-back
cache marks the line "dirty" by setting its dirty-bit in the line's
tag word.  The write-through motherboard simultaneously stores the
write data in data store and begins a DRAM write cycle.  The uP
moves on.

If the tag word doesn't match, what a bummer, it's a cache miss.
If the line in cache is dirty, double bummer, the line must be
copied back to main memory before anything else can happen.  All
16 bytes are copied back, even if the hit was a one-byte write.
This data transfer is called a "dirty write flush."

On a read-miss, the motherboard has to copy a line from main memory
to cache (and update the tag, the whole operation is called a "cache
fill"), and the uP can stop waiting as soon as the bytes it wants
go by.  On a write-miss, the caches I've worked with ignore the
event (that's an oversimplification) and the main memory performs
a write cycle.  I've heard of systems that fill on a write-miss,
that is they replace the cache line whenever it misses, read or
write, dirty or not.  I've never seen such a system.

Terms
-----
The 486, the 68020, and their descendants have caches on chip.
We call the on-chip cache "primary" and the cache on the
motherboard "secondary."  The 386 has no cache, therefore the cache
on a 386 motherboard is "primary."  I like to call the DRAM array
"core" for brevity.  Motherboard = "mb."  Megabyte = "MB."

Problems
--------
I added "core" and I had to disable my secondary cache to
get the board running.  Or, I added core and performance took a dive.
Disabling secondary cache improved it, but still real slow.
What happened?

 Whenever you are adding memory and you cross a power-of-2
address boundary, another address bit becomes interesting to the
tag.  That is, the tag does not care when you add your 8th MB
(MB) but it cares a lot about the new address bit 24 when you add
your 9th MB, or your 17th (bit 25).  Evidently, at the low-price
end of the mb market there are boards with not enough tag RAM
sockets to support all the core they can hold.  Most of these EL
CHEAPO mbs don't even try to use cache in the region beyond the
tag's coverage.  Some of them don't have the logic to stay out or
the BIOS doesn't know to enable it.  These boards just don't run
right.

Do not buy a mb if you are not sure it can cache all of core.  The
worst case is with core fully stuffed with whatever the board claims
to hold, and the smallest cache configuration.  Some motherboards
ask you to add cache when you add core, so that they don't have to
provide for that worst case tag width.  These motherboards may ask
you to move some jumpers in the tag area.  The jumpers control
which address bits the tag looks at.  Do not buy a motherboard if
you don't know how to set all the jumpers.


Q) 2.20  How do I upgrade the size of my cache?

Look in your motherboard manual.  Each motherboard is different.
You will have to add or replace cache RAMs and move jumpers.

Q) 2.21  Do I need to fill the "dirty tag" RAM socket on my motherboard?

[From: cls@truffula.sj.ca.us (Cameron L. Spitzer)]

Perhaps you don't *have* to for the board to run, but the missing RAM
will cost you performance.  Most "write-back" mbs cope with the
missing RAM by treating all lines as dirty.  You get a lot of
unneccessary write cycles; you might even do better with
write-through.

Your bargain-basement no-documentation no-brand mb might not have the
pullup resistor on that socket, and it might run for a second, ten
minutes, or ten years with that pin not driven.  I think it's a
pointless risk to leave the socket empty.

Q) 2.22  How fast do my cache RAMs have to be?

[From: cls@truffula.sj.ca.us (Cameron L. Spitzer)]

Only the person who designed your mb knows for sure.  There is
no simple formula related to clock rate.  However, most people tell
me their 33 MHz mbs' manuals call for 25 ns data store and 20 ns
tag store, and their 40 and 50 MHz mbs want 20 ns data store and
15 or 12 ns tag.  Tqhe tag has to be faster than data store to make
time for the comparator to work.  Do not buy a motherboard if you do
not know what speed and size of cache RAMs it requires in all its
speeds and configurations.

If you're not sure, it doesn't hurt to use faster RAMs than your
manual calls for.  If your manual says 20 ns for location x and you
happen to have 15 ns parts, it's ok to "mix" the speeds.  It's ok to
"mix" RAMs from more than one manufacturer.  However, the faster RAMs
will not buy you more performance.

Q) 2.23  Which is the best cache policy, write-through or "write-back?"

[From: cls@truffula.sj.ca.us (Cameron L. Spitzer)]

For most applications, copy-back gives better performance than
write-through.  The amount of win will depend on your application and
may not be significant.  Write-through is simpler, but not by much any
more.

Q) 2.24  What about an n-way set associative cache, isn't it better?

[From: cls@truffula.sj.ca.us (Cameron L. Spitzer)]

At the high end of the mb market, caches are available with more than
one set.  In these caches, the data store is broken into two or four
parts, or sets, with a separate tag for each.  On a miss, clever
algorithms (such as Least Recently Used) can be used to pick which set
will be filled, because each set has a candidate location.  The result
is a higher hit rate than a direct mapped (single set) cache the same
size can offer.

The primary cache on the 486 is four-way set associative.

Q) 2.25  Which is better, ISA/EISA/VLB/PCI/etc?

[From: ralf@wpi.wpi.edu (Ralph Valentino)]

Here is a quick overview of the various bus architectures available
for the PC and some of the strengths and weaknesses of each.  Some
terms are described in more detail at the bottom.

XT bus:
	8 data bits, 20 address bits
	4.77 MHz
   Comments: Obsolete, very similar to ISA bus, many XT cards will
             work in ISA slots.
	
ISA bus: Industry Standard Architecture bus (aka. AT bus)
	8/16 data bits, 24 address bits (16Meg addressable)
	8-8.33MHz, asynchronous
	5.55M/s burst
	bus master support
	edge triggered TTL interrupts (IRQs) - no sharing
	low cost
   Comments: ideal for low to mid bandwidth cards, though lack of
	     IRQs can quickly become annoying.
	
MCA bus: Micro Channel Architecture bus
	16/32 data bit, 32 address bits
	80M/s burst, synchronous
	full bus master capability
	good bus arbitration
	auto configurable
	IBM proprietary (not ISA/EISA/VLB compatible)
   Comments: Since MCA was proprietary, EISA was formed to compete with
             it.  EISA gained much more acceptance; MCA is all but dead.
	
EISA bus: Enhanced Industry Standard Architecture bus
	32 data bits, 32 address bits
	8-8.33MHz, synchronous
	32M/s burst (sustained)
	full bus master capability
	good bus arbitration
	auto configurable
	sharable IRQs, DMA channels
	backward compatible with ISA
	some acceptance outside of the PC architecture
	high cost
   Comments: EISA is great for high bandwidth bus mastering cards
             such as SCSI host adaptors, but its high cost limits
             its usefulness for other types of cards.

P-EISA: Pragmatic EISA (also Super-ISA)
	(see the description of the HiNT chipset elsewhere in this FAQ)

VLB: VESA Local Bus
	32 data bits, 32 address bits
	25-40MHz, asynchronous
	130M/s burst (sustained is closer to 32M/s)
	bus master capability
	will coexist with ISA/EISA
	slot limited to 2 or 3 cards typical
	backward compatible with ISA
	moderate cost
   Comments: VLB is great for video cards, but its lack of a good bus
             arbiter limits its usefulness for bus mastering cards and
             its moderate cost limits its usefulness for low to mid 
             bandwidth cards.  Since it can coexist with EISA/ISA, a
             combination of all three types of cards usually works best.
             
PCI:  Peripheral Component Interconnect local bus
	32 data bits (64 bit option), 32 address bits (64 bit option)
	up to 33MHz, synchronous
	132M/s burst (sustained) (264M/s with 64 bit option)
	full bus master capability
	good bus arbitration
	slot limited to 3 or 4 cards typical
	auto configurable
	will coexist with ISA/EISA/MCA as well as another PCI bus
	strong acceptance outside of the PC architecture
	moderate cost
   Comments: The newest of the buses, combining the speed of VLB with
             the advanced arbitration of EISA.  Great for both video
	     cards and bus mastering SCSI/network cards.

			=Terms=

Auto configurable:  Allows software to identify the board's
requirements and resolve any potential resource conflicts
(IRQ/DMA/address/BIOS/etc).

Bus master support:  Capable of First Party DMA transfers.

Full bus master capability:  Can support any First Party cycle from any
device, including another CPU.

Good bus arbitration:  Fair bus access during conflicts, no need to
back off unless another device needs the bus.  This prevents CPU
starvation while allowing a single device to use 100% of the available
bandwidth.  Other buses let a card hold the bus until it decides to
release it and attempts to prevent starvation by having an active card
voluntarily release the bus periodically ("bus on time") and remain
off the bus for a period of time ("bus off time") to give other
devices, including the CPU, a chance even if they don't want it.

16Meg addressable:  This limits first party DMA transfers to the lower
16 Meg of address space.  There are various software methods to
overcome this problem when more than 16 Megs of main memory are
available.  This has no effect on the ability of the processor to
reach all of main memory.

Backward compatible with ISA:  Allows you to place an ISA card in the
slot of a more advanced bus.  Note, however, that the ISA card does
not get any benefit from being in an advanced slot, instead, the slot
reverts to an ISA slot.  Other slots are unaffected.


Q) 2.26  *What are the (dis)advantages of ISA/VLB/EISA SCSI?

Q) 2.27  Will an ISA card work in an MCA (PS/2) machine?

No, they will not.  MCA, unlike EISA and VLB, is not backward
compatible with ISA.

Q) 2.28  *What does the "chip set" do?

Q) 2.29  How do I enter the CMOS configuration menu?

[From: burnesa@cat.com (Shaun Burnet)]

        AMI BIOS        Del key during the POST
        Award BIOS      Ctrl-Alt-Esc
        DTK BIOS        Esc key during the POST
        IBM PS/2 BIOS   Ctrl-Alt-Ins after Ctrl-Alt-Del
        Phoenix BIOS    Ctrl-Alt-Esc or Ctrl-Alt-S

Q) 2.30  What is bus mastering and how do I know if I have it?

Bus mastering is the ability of an expansion (ISA/EISA/VLB/MCA/etc)
card to directly read and write to main memory.  This allows the CPU
do delegate I/O work out to the cards, freeing it to do other things.
For all of the above busses, bus mastering capability is assumed.
Unless specifically stated otherwise, you should assume each slot has
this capability.  For cards, this is not assumed.  If you want a bus
mastering card, you should specifically request it and expect to pay
more.  Note that some cards (RLL/MFM/IDE/com) are not available in bus
mastering versions.

Q) 2.31  Can I put an ISA cards in EISA or VLB slots?

Yes, you can put ISA cards in both EISA slots and VLB slots, as both
buses were specifically designed to be 100% ISA compatible.  ISA cards
will not directly effect the performance of EISA/VLB cards; a well
balanced system will have both.  Note, however, that the total
bandwidth of the bus will be split between all cards, so there is a
strong advantage to using EISA/VLB cards for the high bandwidth
devices (disk/video).

Q) 2.32  How should I configure ISA/VLB cards in the EISA config utility?

Only EISA cards matter in the ECU; ISA and VLB entries are only place
markers.  While this is a good way to keep track of IRQ, DMA and BIOS
conflictions, ISA and VLB need not be placed in the configuration at
all, nor should it be assumed that the settings for them match the
actual card settings.  If you wish to add them, you can use the
"Generic ISA Card" configuration file for either.  Do not expect card
vendors to supply them.

Q) 2.33  What is the difference between EISA Standard and Enhanced modes?

Many EISA cards support both Standard (ISA) and Enhanced (EISA) modes.
In Standard mode, the card will appear to be an ISA card to the OS; it
will generate edge triggered interrupts and only accept ISA addressing
(for bus mastering cards), for instance.  An important thing to note
is that the card may still do EISA specific things like 32-bit data
bus mastering and EISA configuration setup as this functionality is
hidden from the OS.

Q) 2.34  Is there any point in putting more than 16M in an ISA machine?

[From: cls@truffula.sj.ca.us (Cameron L. Spitzer)]

Sure.  Even inferior operating systems can use it for something.
The question is how much performance it buys.  In ISA, the DMA
channels and bus-mastering IO cards can only address the first 16 MB.  
Therefore the device drivers have to copy data up and down or just
not use the space.  I am told the Linux SCSI drivers know how to
do this.  I don't know about OS/2 or MSWindows.

Q) 2.35  What disadvantages are there to the HiNT EISA chip set?

[From: ralf@wpi.wpi.edu (Ralph Valentino)]

The HiNT Caesar Chip Set (CS8001 & CS8002) can come in three different
configurations.  All three of these configurations have EISA style
connectors and are (sometimes incorrectly) sold as EISA motherboards.
The differences should be carefully noted, though.

The rarest of these configuration uses a combination of the first HiNT
chip (CS8001) and the Intel chip set.  This configuration can support
the full EISA functionality: 32 address bits, 32 data bits, level
sensitive (sharable) interrupts, full EISA DMA, watch dog (sanity)
timer, and so forth.

The second configuration is called Super-ISA, which uses both of the
HiNT chips.  This configuration is very common in low-end models.  It
supports a very limited functionality: 24 address bits, 32 data bits,
edge triggered (non-sharable) interrupts, ISA (16 data, 24 address)
DMA, and no watch dog timer.  Some EISA boards, such as the Adaptec
1742A EISA Fast SCSI-2 host adapter, can be configured to work in this
mode by hacking their EISA configuration file (.CFG) to turn off these
features.  Other EISA cards require these features and are therefore
unusable in these systems.

The final configuration is called Pragmatic EISA, or P-EISA.  Like
Super-ISA, both HiNT chips are used but external support logic
(buffers and such) are added to provide a somewhat increased
functionality: 32 address bits, 32 data bits, edge triggered
(non-sharable) interrupts, ISA (16 data, 24 address) DMA, and no watch
dog timer.  The full 32 bits for address and data allow bus mastering
devices access to the complete range of main memory.  As with
Super-ISA, there may be incompatibilities with some EISA cards.


Q) 2.36  *Should I change the ISA bus speed?

Q) 2.37  +Why is my PC's clock so inaccurate?

[From: uwvax!astroatc!nicmad!madnix!zaphod (Ron Bean)]

Usually this means that the clock crystal is not adjusted properly, or
that it needs a new battery. The interrupt-based "DOS time" can also
be affected by programs that disable interrupts for too long.
 
   If your clock is just running at the wrong speed, you can
compensate for it in software by measuring the drift rate and applying
a correction factor. In the long run, this can be *very* accurate. One
such program for DOS is adclk100.zip. An alternative is to run a
program that periodically sets your clock to another one that's known
to be accurate (see the question on setting your clock).
 
   If your clock is more erratic (eg, it stops when the machine is
turned off, or the date gets scrambled), try replacing the battery
(but remember to write down your CMOS settings first!).  The CMOS RAM
takes considerably less power than the clock, so it may keep working
even though the battery is too weak to run the clock.
 
   You may have a small lithium "coin" battery soldered to the
motherboard, or a larger external one plugged into a connector.  Some
motherboards have a jumper to select either type, and a few have a
NiCd battery that recharges automatically, or a lithium battery
encapsulated in the clock chip.
 
   The batteries that are soldered in or encapsulated with the clock
chip are supposed to last 10 years or more, but your mileage may
vary. Some people find that the external type has to be replaced every
couple of years. Self-recharging NiCds that get power from a disk
drive cable are available as aftermarket items.  A few people have
tried to save money by substituting 4 alkaline AA batteries for the
expensive external lithium battery, but they have to be replaced more
often. If the battery is encapsulated in the chip, there is no way to
replace it without replacing the chip (these chips can be "turned off"
via software to extend battery life during storage, and are shipped
from the factory that way).
 
   A typical cheap quartz watch is rated at +/- 15 sec per month (3
minutes per year) which is about 5.7 ppm (parts per million).  Dallas
Semiconductor rates their encapsulated clock modules for +/- 1 min per
month, or 22.8 ppm. Clocks with external crystals can be "fine-tuned"
with a trimmer capacitor-- if the motherboard designer included one
(Note: there may be more than one crystal on the motherboard). The
crystal's frequency will change slightly over time as the crystal "ages".
 
   The original IBM AT used the Motorola MC146818, which is a
real-time clock plus 50 bytes of CMOS RAM. This chip is discussed in
the book "The Undocumented PC", from Addison-Welsey. The Dallas
Semiconductor DS1285 is a drop-in replacement for the MC146818, and
the DS1287 is the same chip encapsulated with its own battery and
clock crystal. Other variants include larger amounts of CMOS RAM. Most
software accesses the clock through the BIOS.
 
   Before the AT, there were various types of aftermarket clock cards,
and some of them may still be available (even though every PC sold in
the last several years "already has a clock").
 
   Given the number of times this comes up on the net, there should be
a market for accurate clock cards. On the other hand, most people
don't seem to care whether their computers have anything close to the
correct time. If your machine doesn't keep time correctly, and you
think it should, you might consider complaining to the manufacturer
about it.


Q) 2.38  +How can I automatically set my PC's clock to the correct time?

[From: uwvax!astroatc!nicmad!madnix!zaphod (Ron Bean)]

If you're on the internet, you can use ntp (network time protocol) to
set your clock to another machine that's known to be accurate (see RFC
1129, Internet Time Synchronization).
 
   ACTS, the Automated Computer Time Service, is available by modem at
(303)494-4774 (note this is NOT a toll-free call). There are programs
that will dial this number and set your clock automatically. This
service is run by NIST (the National Institute of Standards and
Technology, formerly the National Bureau of Standards).
 
   In Germany, the Physikalisch-Technische Bundesanstalt (PTB)
broadcasts a coded time signal on 77.5 kHz from a transmitter near
Frankfurt, and inexpensive receivers are available that can plug into
a serial port (this signal should cover most of Europe). In the US,
NIST runs a similar station (WWVB) on 60 kHz, but the data is encoded
differently and receivers are expensive and hard to find.
 
   Other coded time signals are available from WWV and WWVH on 2.5, 5,
10, 15, and 20 MHz (shortwave), and from the GOES and GPS
satellites. CHU Canada on 3.33, 7.335, and 14.670 MHz broadcasts time
codes using Bell 103 FSK (300 baud modem tones) during seconds 31
through 39 of each minute. If you don't have a shortwave receiver, the
WWV audio time announcement can be heard by dialing (303)499-7111
(again, this is NOT a toll-free call).
 
   NIST publishes a 30-page booklet (NIST Special Publication 432)
that explains all of their time services in detail. They also have a
partial list of companies that make receivers, but it appears to be
somewhat out of date. Both are available from:
 
          NIST/Radio Station WWV
          2000 East County Road 58
          Fort Collins, CO  80524-9499
 
   You may have heard about Heathkit's "Most Accurate Clock", which
decodes the time signal from WWV and has a serial port.  Heath no
longer sells kits, but they still sell the factory-built version of
the clock (it's not cheap, though). Their address is P.O. Box 1288,
Benton Harbor, MI 49023.


Q) 2.39  Can I use IRQ2 or is it special?

IRQ2 is used to cascade the second interrupt controller on AT
machines.  This has one and only one side effect: from a software
point of view, IRQ2 = IRQ9.  You can freely use IRQ2 on any hardware
device, provided you are not already using IRQ9.  Your associated
software driver can be set to IRQ2 or IRQ9, which ever it happens to
prefer.  Note that many video cards have an IRQ2 enable jumper for
very, very old backward compatibility reasons; you should disable this
before attempting to use the IRQ for something else.  There are no
unexpected side effects.

Q) 2.40  Where do all the IRQ's go?

[From: wlim@lehman.com (Willie Lim)]

Default settings.

 IRQ   DMA  IO BASE   Card or Device
	    ADDRESS
            (HEX)
 ===   ===  ========  ===============
  0     *      *      timer (reserved)
  1     *      *      keyboard (reserved)
  2     *      *      interrupt 8-15 (cascade)
  2     *     330     MPU-401 Emulation (PAS 16)      
  3     *     2F8     COM2:
  3     *     2F8     COM4:
  3     *     300     3Com Etherlink II, II/TP, II/16, II/16TP, 16/16TP
  3     *     300     Novell NE2000
  3     *     300     SMC/Western Digital 8003EP, 8013EWC, 8013WB
  4     *     3F8     COM1:
  4     *     3F8     COM3:
  5     *     278     LPT2:
  5     *     368     Ungermann-Bass Ethernet NIUpc (long), NIUpc/EOTP (short)
  5     *     ???     DEC etherWORKS LC, Turbo, Turbo/TP
  5     1     220     Sound Blaster Emulation (PAS 16)
  5     5     A20     Proteon P1390
  6     *      *      floppy disk controller
  7     *     378     LPT1: (PRN:)
  7     3      *      Pro Audio Spectrum 16 (PAS 16)  
  8     *      *      clock (reserved)
  9     *      *      reserved
  9     5     300     Boca Ethernet (BEN100, BEN102, BEN300)  
 10     *      *      unassigned
 11     *      *      unassigned
 12     *      *      unassigned
 13     *      *      math co-processor
 14     *      *      hard-disk
 15     *      *      secondary disk controller

===============
Ralph Valentino   (ralf@chpc.org)  (ralf@wpi.wpi.edu)
Hardware Engineer,  Worcester  Polytechnic  Institute
Center for High Performance Computing, Marlborough MA

From ankh.iia.org!babbage.ece.uc.edu!news.kei.com!MathWorks.Com!noc.near.net!chpc.chpc.org!chpc.chpc.org!not-for-mail Sun Aug 14 17:59:05 1994
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From: ralf@chpc.org (Ralph Valentino)
Newsgroups: comp.sys.ibm.pc.hardware.video,comp.sys.ibm.pc.hardware.comm,comp.sys.ibm.pc.hardware.storage,comp.sys.ibm.pc.hardware.cd-rom,comp.sys.ibm.pc.hardware.systems,comp.sys.ibm.pc.hardware.networking,comp.sys.ibm.pc.hardware.chips,comp.sys.ibm.pc.hardware.misc,comp.answers,news.answers
Subject: comp.sys.ibm.pc.hardware.* Frequently Asked Questions (FAQ) Part 2/5
Followup-To: comp.sys.ibm.pc.hardware.misc
Date: 12 Aug 1994 02:07:41 -0400
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Summary: This is a monthly posting containing a list of Frequently
	 Asked Questions (and their answers) pertaining to hardware
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Archive-name: pc-hardware-faq/part2
Last-modified: 1994/08/10
Version: 1.7


S) 3.0 IO controllers/interfaces

Q) 3.1  *How do IDE/MFM/RLL/ESDI/SCSI interfaces work?

Q) 3.2  *How can I tell if I have MFM/RLL/ESDI/IDE/SCSI?

Q) 3.3  Do caching controllers really help?

[From: backbone!wayne@tower.tssi.com (Wayne Schlitt)]

The short answer, is that if you are using a multi-tasking
operating system with a good memory manager, caching controllers
should be ignored.  If you are running DOS or Windows, then *maybe*
they will help, but I am not sure that they are a good buy.  

There are lots of people who have said "I put a caching controller in
my computer, and it runs faster!".  This is probably true, but they
never have measured the speed increase compared to putting the same
memory into main memory instead.  More importantly, the caching
controllers cost more money than non caching controllers, so you
should be able to add _more_ main memory instead of buying a caching
controller.

The following is a shortened up version of a much longer article.  If
you want a copy of the longer article, send me email at
"wayne@cse.unl.edu".

*** Why a multi-tasking operating system?

A multi-tasking operating system can allow the application to continue
immediately after it does a write, and the actual disk write can
happen later.  This is known as write behind.  The operating system
can also read several blocks from the file when the application
requests just part of the first block.  This is known as read a head.
When the application requests the block later on, the block will
already be there and the OS can then schedule some more reads.

A multitasking operating system is required because these operations
can cause interrupts and processing when control has been given back to
the application.  

Basically, operating systems such as DOS, MS-Windows, MacOS and such
do not allow true preemptive multitasking and can not do the read a
heads and the write behinds.  For these systems, the latency of a disk
drive is the most important thing.  The application does not regain
control until the read or write has finished. 

*** The controller can't speed up the disk.

Remember, the bottleneck is at the disk.  Nothing that the controller
can do can make the data come off the platters any faster.  All but the
oldest and slowest controllers can keep up with all but the newest and
fastest disks.  The SCSI bus is designed to be able to keep *several*
disks busy without slowing things down.

Speeding up parts of the system that are not the bottleneck won't help
much.  The goal has to be to reduce the number of real disk accesses.

*** First, isn't the caching controller hardware and isn't hardware
*** always faster than software?

Well, yes there is a piece of physical hardware that is called the
caching controller, but no, the cache is not really "in hardware".
Managing a disk is a fairly complicated task, complicated enough that
you really can't implement the controller in combinatorial logic. 

So, just about all disk controllers and for that matter all disk
drives have a general purpose computer on them.  They run a little
software program that manages the communication between the main cpu
and the disk bus, or the disk bus and the disk.  Often this cpu is put
in with a bunch of other logic as part of a standard cell custom chip,
so you might not see a chip that says "Z80" or such.

So, we are really not comparing "hardware" with "software", we are
comparing "software on the controller" with "software on the main
cpu".

*** Ok, why can the OS win?

Assume that you have a bunch of memory that you can either put into
main memory and have the OS manage the cache, or put on a caching
controller.  Which one will be better?  Let us look at the various
cases. 

For a cache hit you have:

If the OS does the caching, you just have the OS's cache checking
latency.

If the card does the caching, you will have the OS's cache checking
latency, plus the I/O setup time, plus the controller's cache checking
latency, plus you have to move the data from the card to main memory.
If the controller does DMA, it will be taking away from the memory
bandwidth that the main CPU needs.  If the controller doesn't have
DMA, then the main CPU will have to do all the transfers, one word at
a time.

For a cache miss, you have:

If the OS does the caching, you have the OS's cache checking latency
plus the set up time for the disk I/O, plus the time it takes for the
disk to transfer the data (this will be a majority of the time), plus the
cost of doing either the DMA or having the CPU move the data into main
memory. 

The caching controller will have all of the above times, plus it's own
cache checking latency.

As you can see, the caching controller adds a lot of overhead no
matter what.  This overhead can only be offset when you get a cache
hit, but since you have the same amount of memory on the controller
and the main cpu, you should have the same number of cache hits in
either case.  Therefore, the caching controller will always give more
overhead than an OS managed cache.

*** Yeah, but there is this processor on the controller doing the
*** cache checks, so you really have a multi-processor system.
*** Shouldn't this be faster than a single processor?  Doesn't this
*** allow the main cpu to do other things while the controller manages
*** the cache?

Yes, this really is a multi-processor system, but multi-processors are
not always faster than uni-processors.  In particular, multi-processor
systems have communication overhead.  In this case, you are
communicating with the controller using a protocol that is fairly
expensive, with outb instructions and interrupts and such.  The
overhead of communicating with this other processor is greater than
the overhead of just checking the cache on main cpu, even if the main
cpu is very slow.  

The multi-processor aspect just doesn't help out when you are talking
about managing a cache.  There is just too much communication overhead
and too little processing for it to be a win.

*** Ok, but couldn't the caching controller do a better job of
*** managing the cache?

Both the controller and the OS are going to be executing a piece of
software, so in theory there isn't anything that the slower cpu on the
controller can do that the OS can't do, but the OS can do things that
the controller can't do.

Here are some of the things that the OS can do better:

* When you read a block from a file, the OS can read several more
  blocks ahead of time.  Caching controllers often will read an entire
  track in order to simulate this file read a head, but the rest of
  the file isn't always on the same track, only the OS knows where the
  blocks are really going to be at.  This can lead to wasted time and
  cache memory reading data that will never be used.

* In order to improve file system reliability, some writes _must_
  complete immediately, and _must_ complete in the order that they are
  given.  Otherwise, the file system structures may not be left in a
  coherent state if the system crashes.

  Other writes can be completed as time is available, and can be done
  in any order.  The operating system knows the difference between
  these cases and can do the writes appropriately.

  Caching controllers, on the other hand, don't know if the write that
  it was just given _must_ be written right away, or if it can wait a
  little bit.  If it waits when it shouldn't, you are risking your
  file system and data.  

* Sometimes, you want a large disk cache if you are accessing lots of
  data off the disk.  At other times, you want a small disk cache and
  more memory left to programs.  The operating system can balance
  these needs dynamically and adjust the amount of disk cache
  automatically.

  If you put the memory on a caching controller, then that memory can
  _only_ be used for disk caches, and you can _never_ use more.
  Chances are, you will either have too much or too little memory
  dedicated to the cache at any give time. 

* When a process closes a file, the operating system knows that the
  blocks associated with that file are not as likely to to be used
  again as those blocks associated with files that are still open.
  Only the operating system is going to know when files are closed,
  the controller won't.  Similar things happen with processes.

* In the area of Virtual Memory, the OS does an extremely better job
  of managing things.  When a program accesses a piece of memory, the
  CPU will do a hardware level check to see if the page is in memory.
  If the page is in memory, then there will basically be no delay.  It
  is only when the page isn't in memory that the OS gets involved.

  Even if all of those extra pages are sitting in the
  caching controller's memory, they still have to be moved to main
  memory with all the overhead that that involves.

  This is why dynamic caches vs program memory is so important.

*** What is the "Memory Hierarchy" and how does this relate to
*** caching controllers?

The basic idea of a memory hierarchy is to layer various types of
memory, so that the fastest memory is closest to the cpu.  Faster
memory is more expensive, so you can't use only the fastest type and
still be cheap.  If a piece of data isn't in the highest (fastest)
level of the hierarchy, then you have to check the next level down.

In order for a memory hierarchy to work well, you need to make sure
that the each level of the hierarchy has much more storage then the
level above it, otherwise you wont have a high hit rate.

The hierarchy on a 486 goes something like this:

8 regs << 8k on chip cache << 256k off chip cache << main memory << disk

If you are going to put something between main memory and disk, it
needs to be much larger than main memory in order for it to be
effective. 

*** What about all these neat things that a caching controller can do
*** such as elevator seeking, overlapping seeks with reads and writes,
*** scatter/gather, etc...

These are nice features, but they are all done by either the OS or a
good SCSI controller anyway.  None of these things are at all related
to supporting the cache, so you shouldn't buy a caching controller for
just these features.

*** Ok, you have talked about things like Unix, OS/2 and Windows NT,
*** but what about DOS and MS-Windows?

Well, here things get a lot grayer.  First, older versions of DOS have
notoriously bad disk cache programs.  Since neither DOS nor MS-Windows
are preemptive multi-tasking systems, it is much harder to do read a
head.  Also, since DOS/MS-Windows users are used to being able to
power off their computers at any time, doing write behind is much more
dangerous.  DOS and MS-Windows also can crash much easier than these
other OS's, so people might reboot for many reasons.  

Caching controllers usually leave the hard disk light on when they
have data that hasn't been written out, and people don't usually power
their computer off until that light goes out.  This lets the
controllers do write behind fairly safely.  (But you can still loose
power, so this isn't risk free.)  They also do crude read a heads by
prereading entire tracks.

DOS also runs in real mode and real mode can only access 640K of
memory.  This mean that a disk cache can be real helpful.
Unfortunately, to do a software based disk cache, the cpu has to be
switched into protected mode in order to access memory beyond the 640K
boundary and then you have to switch back into real mode.  Intel,
however forgot to make it easy to switch back to real mode.   All in
all, this switching back and forth ends up being real expensive.  This
_might_ be more expensive than just using a caching controller, I
don't know.

So, it is possible that if you configure DOS to not use a cache, and
get a caching controller, then you might be a head.  I really don't
know much about this area.  I have not done any real timings of this.

*** So, when would you ever want to buy a caching controller?

The answer is not too often, but there are a few cases that I can
think of:

* You have filled up all your SIMM slots on your motherboard and in
  order to add more memory you would have to throw some out.  This is
  a real shaky reason.  You can always sell your old memory, or move
  it to another computer.  The jump from 4 1MB SIMMs to 4 4MB SIMMs is
  large, but you will be much better off in the long run with more
  main memory.

* You have maxed out your memory and you need it all for programs and
  data.  If you can't put any more memory on the mother board, then
  you don't have many choices.

* If you have a bunch of slow (100ns-120ns) memory left over from say
  a 286 or something and you can't use it on your motherboard because
  it is too slow, then maybe adding it to a caching controller
  will help.  Be careful however, if your hit rates on the caching
  controller are too low, then you may be just adding overhead without
  getting any benefits.

* If you are stuck with a bad OS because that's what your applications
  run on, then you might be better off with a caching controller.

*** What about those disk drives that come with caches, are they bad too?

Don't confuse caching disk controllers with cache on disk drives.  The
latter is actually useful.  The little cpu on the disk drive has to
read every byte that comes off the disk in order to see when the
sector that you are interested in has come under the heads and to do
any error detection and correction.  The disk also has to have buffers
in case the bus is busy, and to sync up the speeds of the bus and the
heads.

Since all this data is going though the cpu on disk drive and you have
to have a buffer anyway, just making the buffer larger and saving the
entire track is an easy win.  Saving a couple of the most frequent
tracks is also a win.

Most of these caches on the disk drives are fairly small (64k-256k),
and a single memory chip will give you about that amount of memory
anyway, so you aren't wasting many resources.  This also allows the OS
to always assume that interleaving is not necessary to get full disk
throughput, even if it does a fair amount of processing between disk
requests. 

Q) 3.4  Do IDE controllers use DMA?

No, they do not.  This is a rumor that keeps popping up.  This may
change on the next revision of the standard.

Q) 3.5  Why won't my two IDE drives work together?

[From: jruchak@mtmis1.mis.semi.harris.com (John Anthony Ruchak)]

Assuming that the drives are attached to the same controller and they
work properly when attached one-at-a-time, you probably don't have
them configured properly for Master/Slave operation.

When operating 2 IDE drives, one must be designated as "Master" and
the other as "Slave."  There are jumpers on every IDE drive to
configure this.  Check your hard drive manuals for the jumper settings
for your drives.  In general, it doesn't matter which is which - just
pick one as master, and make the other slave.

In your CMOS configuration, Drive 1 should have the parameters (heads,
cylinders, etc.) that match the drive you set as "Master" and Drive
2's parameters should match those of the "slave" drive.  In operation,
the Master will appear as drive C: and the slave as drive D:.

Because not all hard drive manufacturers follow the IDE specifications
closely enough, drives from 2 different manufacturers may not work well
together.  In this case, changing master -> slave and slave -> master
(along with the appropriate CMOS changes) may help.  If it doesn't,
then trying two drives from the SAME manufacturer is the only avenue
you have left.

Q) 3.6  Which is better, VLB or ISA IDE?

[From: pieterh@sci.kun.nl]

If a simple answer is what you want, then yes, in general VLB IDE
controllers are better than ISA ones.  If you are purchasing or
putting together a computer, the relatively small price difference
makes the choice for a VLB controller a sensible one.

However, if you already have an ISA controller and are wondering
whether it's worth upgrading to VLB, it's not that easy.  VLB may be
faster in principle, the question is if you're going to notice it.


 *** The Bottlenecks

Let's take a look at what the limiting factors are in the path the
data travels from your drive platter to the CPU.

1. Raw data transfer from the drive platter.  To find out what this
   rate is, you need the spec sheet for your drive.  Remember that
   it is dependent on the cylinder, so a single drive can give
   different results depending on where on the drive you're testing.
   
   Anyway, this transfer rate is 1 to 2 MB/s on most IDE drives,
   depending on data density and rotational speed.

2. The data has to be digested by the drive's onboard controller,
   which not only mediates between the drive hardware and the IDE
   bus, but also manages the buffer cache.  Let's hope it's both
   fast and intelligent (not always the case *sigh*).
   
3. Data transfer over the IDE/ATA bus (2-3MB/s with standard
   timing).  The actual speed depends on the timing used; some
   drives and controllers support faster timing.  Enhanced IDE
   (IDE-2) can transfer up to 11 MB/s.
 
4. Transfer from the interface to the CPU (ISA: max 5 Mb/s, VLB:
   10-80 MB/s depending on CPU clock, wait states, interface...)
 
A generic IDE interface is usually not able to get the most out
of the ISA and IDE bandwidths (3 and 4); a typical upper limit is
about 2 MB/s if you use block transfers (see below), 2.5 MB/s if
you're willing to push the ISA bus clock a little (more about
that later on).

Still, it's clear that on all but the fastest drives the raw data
transfer rate to/from the drive platter (1) will determine the
maximum performance you're going to get.  If you're getting
transfer rates near this limit, you can't significantly improve
your throughput whatever you do.


 *** Tuning Your Harddisk

Suppose your harddisk throughput is lower than you think is
possible with your drive.  How can you tune your system to improve
hard disk performance?  I'll go through points 1-4 again and
indicate what you can do to widen up the bottlenecks a little.

1. Drive platter to head transfer.
    - Sorry, there's nothing you can do short of getting a new
      drive.
      
2. The drive controller.
    - Many modern drives understand "block transfer", also known as
      multi-sector I/O or read/write multiple.	Although the newest
      BIOSes have this feature built in, most of us will have to
      use a driver.  More about that at the end of this section.
      
      What is block transfer?  Normally, for each sector the
      computer wants to read from or write to the drive, it has to
      issue a separate command.  When you're transfering 2 MB/s,
      that means you're sending the drive 4,000 commands each
      second.  Each command has to be issued by the CPU, transferred
      over the ISA and IDE buses, interpreted and acted upon by the
      drive's onboard controller.  Every such command takes a little
      time.
   
      By using block transfer mode, it is possible to read or write
      more than one sector (usually 4 to 32) using a single command.
      This greatly cuts down command overhead, as you can imagine,
      and may very well have a dramatic effect on a badly performing
      system.  In most cases, it will improve performance by 5-20%.
      
      Unfortunately some older drives have inferior support of this
      feature and actually slow down...  or in exceptional cases
      even hose your data.

3. The IDE bus.
    - With most drives you can use faster IDE bus timing, but your
      interface has to support this.  Modern IDE interface chips
      often have completely programmable timing; these can be
      exceptionally fast if the software supports this feature and,
      of course, if the drive can keep up.  Some controllers use
      jumpers to configure timing.

      The last word in IDE bus bandwidth is of course the Enhanced
      IDE bus, which allows exceedingly fast transfers if both
      drives and interface support it.

      If you cannot use improved timing with a new VLB interface,
      the IDE bus will prove to be as much as a bottleneck as the
      ISA bus was.

    - Not all interfaces are created equal, some are better
      engineered.  With the current VLB hype, there's bound to be
      a friend who has an old (ISA) interface gathering dust; try
      that one.

4. The ISA bus.
    - The official speed of the ISA bus is about 8 MHz, but most
      cards, especially modern ones, will work fine on 11 MHz or
      more (some will even take as much as 20 MHz).  If you don't
      mind experimenting, it may be worthwhile to see if your
      ISA cards run reliably at a higher bus clock.  This is
      especially interesting if your drive nears the 2MB/s mark.

      The BIOS setup has to support this, of course.

      *WARNING* Pushing the ISA bus clock beyond spec often works
      well, but there is always the risk that it DESTROYS YOUR
      DATA.  Make a backup before attempting this and thoroughly
      verify correct operation before entrusting critical jobs to
      a "pushed" system.

    - Finally, if you need more than the 2.5-3 MB/s or so you can
      squeeze out of a good ISA controller, VLB is the way to go.
      Be aware that the controllers on the market are of variable
      quality; VLB alone isn't going to be enough if you need the
      highest performance.  It has occurred that a VLB interface
      proved to be, all things equal, slower than the ISA one it
      replaced!

      Take special note of the drivers: they must be stable and
      support whatever software you intend to use (DOS, Windows
      32-bit VxD, OS/2).  Without a driver loaded, the VLB
      interface will perform no better than an ISA controller.

A final word about block transfer drivers.  VLB controllers are
usually shipped with a TSR that, among other things, enables block
transfers (usually designated "Turbo" mode)---this is often where
most of the performance gain actually comes from.  But block mode
is equally possible using ISA based interfaces.  Popular block
transfer drivers are Drive Rocket and DiskQwik.  You can get a
crippled version of the latter from Simtel:

	pub/msdos/diskutil/dqwik110.zip

If you're using Linux, you can use Mark Lord's IDE performance
patches to enable block mode.  In true multitasking operating
systems, block transfers have the additional advantage of greatly
reducing CPU load.


Q) 3.7  How do I install a second controller?

[From: strople@ug.cs.dal.ca (PAUL LESLIE STROPLE)]

The following should solve about 95% (9.5?) of second controller
problems, if only to tell you it can't be done!
 
Generic Second Controller Installation:

1) Normally the MFM/IDE/RLL controller is set up as the primary, and
the ESDI/SCSI as the secondary; One reason for this is because the
ESDI/SCSI controller cards are usually more flexible in their set up
and secondly this method seems to work (probably due to reason one).
 
2) Your primary controller is set up using all the normal defaults:
   - Floppy  at primary address(3F0-3F7).
   - Hard disk enabled, at primary addresses (1F0-1F7),
BIOS address C800 and interrupt 14.
 
3) Your secondary controller is set up as:
   - Floppy drives disabled
   - Hard disk controller enabled, secondary address(170- 177) and
     interrupt 15.
   - NOTE: onboard bios set to D400, or D800 can be used, if there is a
     conflict.
 
4) Computer BIOS Setup:
   - Any drive(s) on the primary controller (MFM/IDE), should be
     entered in the BIOS setup as usual.
   - You DO NOT enter the drive types for the hard disks on the
secondary controller, even if there are only two drives in the entire
system i.e., if one drive on each controller you only enter the drive
type of the hard disk on the primary controller -- the 2nd drive type
is left as not installed (0).
 
Operating System:
 
If you do the above steps you now have the hardware setup correctly;
your only other problem may be with the operating system.
 
Different OSs handle secondary controllers differently; as well,
different controllers handles same OSs differently (scared yet?).
 
For example: with DOS you may require a device driver (available from
the manufacture or through third party companies, such as Ontrack
Computer Systems -- more on Ontrack later). Some flavors of UNIX
handle a mixture of controllers better than others (e.g., IA 5.4 had
probs mixing ESDI and SCSI controllers under certain conditions).
 
Procedure:
 
You should verify that your secondary controller, and associated hard
drives, are working properly (you can try this by installing it as the
primary system -- removing existing system first!).  Follow above
steps 1 to 4, pray, and turn on system! If it still won't work you may
need additional drivers. First check with the supplier or manufacture
(I know, for example, a DTC ESDI controller comes with the DOS drivers
included, and it works perfectly).
 
I am not sure of operating systems supported by Ontrack Data Systems.
I know that their DOS driver can assist secondary controllers, even
allowing two IDEs to co-exist. Likewise, the drivers can also install
virtually any drive, regardless of what is supported by the BIOS.
 
BIG NOTE: The features required in a secondary controller a normally
not found on a $30.00 IDE controller. The best thing to do it, if
possible, is to get a guarantee from the supplier/manufacture that if
it doesn't work (and they can't make it) then they will take it back.
 
Ontrack supplies a complete range of hard disk products and services
-- from driver software, data recovery services, to media and data
conversions (including tape backups).  The product I know them from is
DiskManager.
 
Disk Manager is a utility for hard disk management. It will allow you
to setup and install virtually any hard disk, regardless of disk's
layout and BIOS options available. Disk Manager (version greater than
5.2.X, or there abouts) includes a driver for co-resident controllers.
For driver to work the co-res board must be able to hit the above
addresses and must be WD1003 AT command set compatible (this includes
most IDE and ESDI boards).
 
DM contains a number of features, including full diagnostics.  You may
not need to know the disk's geometry, as there are numerous layouts
stored internally. All you need to do is select the correct model and
DM does the rest.
 
To contact Ontrack: U.S.  (800)-872-2599; UK 0800-24 39 96 this is
either an address or phone number! outside U.K. (but NOT U.S.)
44-81-974 5522

Q) 3.8  Which is better, SCSI or IDE?

[From: ralf@wpi.wpi.edu (Ralph Valentino)]

IDE vs SCSI

Non-issues:
1) SCSI and IDE devices cost approximately the same for the same
   features (size, speed, access time).  Shop around for good prices.

Advantages of IDE:
1) faster response time (low request overhead)
2) hard drive interface is compatible with RLL/MFM/ESDI: any driver
for one (including the main system BIOS) will run the other.
3) IDE controllers are considerably cheaper ($150 and up) than SCSI
   host adapters. 
4) Will always be the boot device when mixed with SCSI.

Advantages of SCSI:
1) Supports up to 7 devices per host adapter.  This saves slots,
IRQ's, DMA channels and, as you add deviceds, money.
2) Supports different types of devices simultaneously the same host
adapter (hard drives, tape drives, CDROMs, scanners, etc).
3) SCSI devices will work in other systems as well (Mac, Sparc, and
countless other workstations and mainframes).  If you change platforms
in the future, you will still be able to use your SCSI devices.
4) Automatically configures device type, geometry (size), speed and
even manufacturer/model number(SCSI-2).  No need to look up CMOS
settings.
5) Busmastering DMA (available in all but a few cheap SCSI host
adapters) decreases amount of CPU time required to do I/O, leaving
more time to work on other tasks (in multitasking OS's only).
6) Software portability - drivers are written for the host adapter,
not the specific device.  That is, if you have a CDROM driver for your
host adapter, you can purchase any brand or speed SCSI CDROM drive and
it will work in your system.
7) Will coexist with any other type of controller (IDE/RLL/MFM/ESDI)
or host adapter (other SCSI cards) without any special tricks.  SCSI
host adapters do not take up one of the two available hard drive
controller port addresses.
8) greater bandwidth utilization (higher throughput) with multiple
devices.  Supports pending requests, which allows the system to
overlap requests to multiple devices so that one device can be seeking
while the second is returning data.
9) Ability to "share" devices between machines by connecting them to
the same SCSI bus.  (note: this is considerably more difficult to do
than it sounds).
10) Bridges are available to hook RLL and ESDI drives to your SCSI host
adapter.  (note: these tend to be prohibitively expensive, though).

Warnings:
1) With otherwise equal drives, IDE will perform better in DOS due to
low command overhead.  SCSI, however, will perform better in
multitasking OS's (OS/2, Unix, NT, etc).  If you see speed comparisons
(benchmarks), make sure you know what OS they were run under.
2) Most benchmarks only test one aspect of your system at a time, not
the effect various aspects have on each other.  For instance, an IDE
drive may get faster throughput but hurt CPU performance during the
transfer, so your system may actually run slower.  Similar confusions
arise when comparing VLB and EISA host adapters.
3) When comparing two systems, keep in mind that CPU, memory, cache,
and bus speed/type will all effect disk performance.  If someone gets
great I/O performance with a particular controller/drive combination
on his Pentium, you should not expect your 386SX-25 to get such I/O
performance even with the exact same controller/drive combination.
4) Similarly sized or even priced drives may not perform equally, even
if they're made by the same manufacturer.  If you're going to compare
two drives, make sure they have the exact same model number.  (IDE
drives usually have an 'A' and SCSI drives usually have an 'S'
appended to their model number).

Q) 3.9  Can MFM/RLL/ESDI/IDE and SCSI coexist?

The PC is limited to two drive controllers total.  SCSI, however, is a
"host adapter" and not a drive controller.  To the rest of your
system, it appears more like an ethernet card than a drive controller.
For this reason, SCSI will always be able to coexist with any type
dive controller.  The main drawback here is that on most systems, you
must boot off a disk on the primary drive controller, if you have one.
That means if you have SCSI and IDE in your system, for example, you
can not directly boot from the SCSI drive.  There are various ways to
get around this limitation, including the use of a boot manager.

Q) 3.10  What's the difference between SCSI and SCSI-2? Are they compatible?

The main difference between SCSI and SCSI-2 are some new minor
features that the average person will never notice.  Both run at a
maximum 5M/s.  (note: Fast and Wide SCSI-2 will potentially run at
faster rates).  All versions of SCSI will work together.  On power up,
the SCSI host adapter and each device (separately) determine the best
command set the speed that each is capable of.  For more information
on this, refer to the comp.periphs.scsi FAQ.

Q) 3.11  Can I share SCSI devices between computers?

There are two ways to share SCSI devices.  The first is removing the
device from one SCSI host adapter and placing it on a second.  This
will always work if the power is off and will usually work with the
power on, but for it to be guaranteed to work with the power on, your
host adapter must be able to support "hot swaps" - the ability to
recover from any errors the removal/addition might cause on the SCSI
bus.  This ability is most common in RAID systems.

The second way to share SCSI devices is by connecting two SCSI busses
together.  This is theoretically possible, but difficult in practice,
especially when disk drives are on the same SCSI chain.  There are a
number of resource reservation issues which must be resolved in the
OS, including disk caching.  Don't expect it to 'just work'.

Q) 3.12  What is Thermal Recalibration?

When the temperature of the hard drive changes, the media expands
slightly.  In modern drives, the data is so densely packed that this
expansion can actually become significant, and if it is not taken into
account, data written when the drive is cold may not be able to be
read when the drive is warm.  To compensate for this, many drives now
perform "Thermal Recalibration" every degree C (or so) as the drive
warms up and then some longer periodic interval once the drive has
reached normal operating temperature.  When thermal recalibration
takes place, the heads are moved and the drive may sound like you are
accessing it.  This is perfectly normal.

If you're attempting to access the drive when thermal recalibration
occurs, you may experience a slight delay.  The only time this becomes
important is when you're doing real-time operations like recording /
playing sound or video.  Proper software buffering of the data should
be able to hide this from the application, but software seldom does
the proper thing on its own.  Because of this, a few companies have
come out with special drive models for audio/video use which employ
special buffering techniques right on the drive.  These drives, of
course, cost significantly more than their counterparts.  Some other
drives offer a way to trigger thermal recalibration prematurely (thus
resetting the timer), so if your real-time operation is shorter than
the recalibration interval, you can use this to assure your operation
goes uninterrupted.  Disabling or delaying recalibration is dangerous
and should be completely avoided.  For more information on the thermal
recalibration characteristics of a drive, contact the drive
manufacturer directly.

Q) 3.13  How do I swap A: and B:

[From: rgeens@wins.uia.ac.be (Ronald Geens)]

To swap A: and B: drives :
1) open up your machine to see if look at the cable that interconnects
the 2 drives.
2) if the cable is twisted, there is no problem, just switch the
connectors from 1 drive to the other.And change the bios-setup.
3) if the cable isn't twisted (which is very,very rare), it's a little
harder: leave the cables as they are, but change the jumpers on the
drive. (this sounds a lot tougher, but it can usually be done without
to much hassle.  When the cable connecting the 2 drives is just a flat
one (like the harddisk cable) then you must play with the jumpers on
the drives: Most of the time, there is a jumper with 4 pins, with the
following layout:
                               _
                              |1|
			     |2*3|
                              ---

Where the * is the 4th unnumbered pin. Normally the A: drive will have a 
jumper on pin 2 & 4 and the B: drive on 1 & 4. Just change these jumpers 
around, (i.e. new A: 2&4, new B: 1&4) and change the BIOS configuration.
4) Don't panic if it doesn't work, just make sure all cables are
conected properly and if that doesn't work just restore everything to
its old state.
PS. By twisted cable, I mean that between the A: and B: drive, a few
wires of the flat cable are turned around.

[From: sward+@CMU.EDU (David Reeve Sward)]

I have found two ways to do this: I originally switched their
positions on the cable attached to the controller, and changed the
BIOS to reflect this.  I recently got a gsi model 21 controller for my
IDE drive, and this controller allows you to specify which drive is A:
and B: in software (it lights the LEDs in turn and asks which is A:
and which is B:).  This did not require a cable change (but I still
changed by BIOS).

Q) 3.14  My floppy drive doesn't work and the light remains on, why?

If you've played around with the floppy cables at all, chances are you
put one of them on backwards.  In general, floppy cables aren't keyed
to prevent this.  Carefully find pin 1 on all floppy drives and the
floppy controller and make sure they all line up with pin 1 on the
cable.  If you have trouble with this, "How do I find pin 1..."
elsewhere in this FAQ may be of some help.

Q) 3.15  What is a 16550 and do I need one?

The 16550 is a UART with two 16 byte FIFOs.  A UART is the part of a
serial port that takes byte-wide (characters) data and converts it to
bit-wide (serial) data, and visa versa.  The FIFO is a buffer which
can hold characters until the CPU is ready to remove it or until the
serial line is ready to transmit it.  The 'normal' UART in the PC (the
8250 or 16450) only has 1-byte FIFOs.  The additional 15 bytes can be
useful when the CPU is busy doing other things - if the CPU isn't able
to remove data fast enough, it will be lost.  The OS or program has to
explicitly support 16550 to make full use of its advantages.

A very important thing to note is that under DOS, the CPU doesn't have
anything else to do, so the 16550 is wasted.  Only under multitasking
operating systems does it really become useful.  The 16550 will *not*
make your file transfers any faster, it will only prevent data from
being lost and relieve your CPU of some overhead.  If you notice
system performance dropping like a rock when file transfers are
occurring, a 16550 may be helpful.  If you see re-transmissions (bad
packets) or "FIFO overrun's" during file transfers under a
multitasking OS, try the same thing under DOS - if the errors go away,
then chances are a 16550 will be useful.  If they remain, then your
problem is likely to be elsewhere.

Q) 3.16  *Are there any >4 serial port cards?

Q) 3.17  Should I buy an internal or external modem?

[From: arnoud@ijssel.hacktic.nl (Arnoud Martens)]

While low speed modems are often only produced as an internal PC card,
most modem manufacturers provide two versions of their higher speed
modems:

1: internal ISA bus card, specially designed to work with the
standard PC bus. You just plug it in and configure it to use on
port.

2: external modem that has to be connected to the serial ports of
your PC (com 1-4), using a serial RS232 cable.

In most cases the functionality of these two is equal. There are
however some differences in using, maintaining and buying these
modems. It is very difficult to give an definite answer as to which one
is better, it completely depends on your own situation. Some of the
points that are in favor of an external modem are:

  * It has lights showing the status of the connection, this can be
    useful in those (rare) cases that you have problems with the
    connection.

  * It can be used on a wide range of systems. External modems
    are connected using a RS232 cable, a standard that most computer
    systems support. So you can as easily use your external modem
    on a Mac, Amiga or Unix box as on your PC. 

  * It doesn't consume power inside the PC (it uses a normal net
    adapter), and doesn't produce any heat inside your PC.

On the other hand the internal modem has also a couple of advantages
compared to an external modem:
   
  * It is always cheaper, Somewhere in the order of 10% less compared
    to the same external modem.

  * It doesn't need special serial hardware since it has already
    been integrated on the board, which will make it even more
    cheaper. 
   
So basically if portability of your modem is an issue, you are better
of with an external modem. But if you only intend to use the modem
with your PC and don't have any power problems, an internal modem is
the best choice.

Q) 3.18  What do all of the modem terms mean?

[From: arnoud@ijssel.hacktic.nl (Arnoud Martens)]

A modem (MOdulator-DEModulator) is a device capable of converting digital
data from your computer into an analog signal that is suitable for
transmission over low band width telephone lines. A modem thus makes it
possible to connect two computers over a telephone line and exchange data
between them.

Basically a modem picks up the phone, and dails a number. A modem on
the other side will pick up the phone and the two modems will
negotiate which protocol to use. When they agree the actual
transmission of data can begin.

The major feature of a modem is the speed that it can achieve
connecting to other modems. This speed is often expressed in baud or
bits per second. The first is a feature of the line and specifies how
much of the bandwidth of the phone channel is used and is fixed to
2400 baud. A baud is defined as the number of lines changes per
second. Bits per second is the actual amount of data transmitted in
one second. Most modems are capable of sending more than one bit per
line transition by using very intelligent signal modulation
techniques. So the bps can be eight times higher compared to trhe baud
rate.

The modulation techniques that a modem uses are standarized by the
ITU-T ( former CCITT), so that modems of different brands can connect
to each other as they use the same modulation schemes. These standards
are often incorporated in a protocol definition that is referred to by
the letter V followed by a number. The most common protocols are:

    V21: (300 baud)
    V22bis: (2400 baud)
    V32: (9600 baud)  
    V32bis: (14400 baud)

A modem is often advertised only by its fastest protocol, most of these
modems "speak" slower protocols as well.

There are also standards on using data compression by the modem, such as MNP5
and V42bis, and error control protocols (V42 and MNP4). These standards can
reduce the transmitted data by a factor four, by using advanced compression
techniques. 

To give you an idea a how fast fast is in modem technology: V32bis transmits
somewhat like 1600 characters per second (that is ~33% of 1 page of
text). Transferring a file of 1Mb takes about 12 minutes. Using V42bis can
speed up transmission to 4000 characters per second for uncompressed data.

Apart from these standardized protocols there are also faster protocols which
are supported by some modem manufacturers. But remember anything faster than
14k4 is *not yet* standarized, and often different manufacturers use their
own modulation scheme that allows only their own modems communicate at that
speed. The most common high speed protocols are:

    V32 terbo (19200 baud)
    V34 (28800 baud) or Vfast. 

The standard for V34 is being worked on, it will be released somewhere in
1994. Some modem manufacturers already sell modems with the (prelimenary) V34
standard. If you are serious about buying a fast modem, upgradability to this
standard should be provided by the manufacturer.

When you use your modem it is important to differentiate between command
status and connect status of your modem. When you are connected to an another
modem everything you send to the modem, will be transmitted to the other
modem. In command mode everything you type will be recieved and interpreted
by the modem. Command mode allows you to change the default settings for
youyr modem.

In command mode it is likely that your modem will respond to the Hayes AT
command set. "AT commands" all have prefix AT, and can be used to change the
(default) settings of your modem. To check if your modem works, fire up a
terminal program (such as kermit), connect to your modem (in kermit c
[ENTER]) and issue AT [ENTER], if your modem works it should respond with
OK. For a list of all "AT commands" see the manual of your modem, as most AT
commands are modem specific.

If you buy a fax-modem, you should pay attention to a couple of things. First
the modem must support Class 2 fax commands, furthermore automatic fax mode
selection is a big pro. That means if you receive a call the modem is capable
of detecting a fax message or a modem connection and act properly (start up a
fax receiving program or spawn something like a login process on the
connection).

Finally there is no best modem to get, brands and qualities change very fast,
as do the prices. If you are interested in buying one, subscribe to the
newsgroup comp.dcom.modems, most postings in this group are very brand
oriented and you will recognize fast enough which users are satisfied over
their modems and which are not.

Q) 3.19  What kinds of sound cards are avalable?

This is covered in the comp.sys.ibm.pc.soundcard FAQ, archive name:
PCsoundcard/soundcard-faq.  Please refer to this document for more
information.

Q) 3.20  Where can I find EISA/VLB sound and IO cards?

Chances are that you won't be able to find them anywhere, and if you
do, they won't be worth the money.  Sound and IO cards have very low
bandwidth requirements, over 10 times lower than the ISA bandwidth and
over 60 times lower than the EISA bandwidth.  For this reason, there
is no advantage in placing them on the more expensive EISA/VLB cards
when the less expensive ISA will more than suffice, especially
considering than all ISA cards will work in an EISA/VLB slot.

Q) 3.21  How does the keyboard interface work?


[From: jhallen@world.std.com (Joseph H Allen)]

The IBM keyboard is connected to the computer through a serial interface
similar to a COM port.  When you press a key, the keyboard sends a
"scan-code" for that key to the computer.  When you release the key, the
keyboard sends a release code to the computer.  If you hold down one key and
press and release another key, the computer will receive the scan-code for
the held key and a scan and release code for the other key.  Since the
release code for the held key was not received, the computer knows that the
held key was down while the other key was pressed.  In this way, the
computer can handle the Shift, Alt and Ctrl keys (and any key could work
like a shift key, since all keys work alike).  The ROM BIOS in the computer
buffers the data from the keyboard, translates the scan-codes to ASCII and
handles the operation of the shift and lock keys.  The keyboard itself also
has a small buffer and there is hardware flow-control for preventing
overruns.  All of this seems simple and quite elegant, but by the time we
get to the AT keyboard the details of the implementation are so complicated
as to ruin an otherwise ideal keyboard.

The XT keyboard's interface almost captures the above elegance (indeed it is
the only elegant thing about the XT, IMHO).  The interface uses a 5-pin DIN
connector with these signal assignments:

     1     CLK/CTS (open-collector)
     2     RxD
     3     RESET
     4     GND
     5     +5V

When the keyboard has a byte to send to the computer, it shifts 9 bits out
to the data line (RxD) with nine clock pulses on the CLK line.  The data
format is 1 start bit, followed by 8 data bits.  The baud rate is roughly
2000 bits per second and is not precisely defined.  Once a byte is
completely transmitted, the computer holds the Clear-To-Send (CTS) line low
to prevent the keyboard from sending any more bytes until the keyboard
interrupt handler reads the current one.  Usually a simple 9-bit clearable
TTL shift register is used to receive keyboard data.  The 9th bit of the
shift register is used to drive an open-collector buffer connected to the
CTS line.  When the start-bit gets all of the way through the shift
register, it holds the CTS line low itself.  Once the CPU reads the
assembled byte, it has only to clear the shift register to release the CTS
line and allow another byte to be received.  Three TTL chips or a single PAL
can implement an entire XT keyboard interface.

The data bytes which the XT sends are also simple.  Codes 0-127 are the
scan-codes.  Codes 128-255 are the release codes- they're the same as the
scan codes, but with the high bit set.  The XT keyboard has only 84 keys, so
not all of the scan-codes are used.

The only problems with the XT keyboard are the lock-status lights
(Caps-lock, Scroll-lock and Num-lock) and the key repeat mechanism.  The
lock-status lights can get out of sync with the computer's idea of which
lock keys are activated, but this only happens if someone resets the
keyboard by unplugging it temporarily.  When you hold a key down long
enough, the keyboard starts repeating the scan-code for that key.  The
release code is still only transmitted once, when the key is released.  The
problem here is that the delay to the start of the repeats and the repeat
rate were made too slow.  Of course, the keyboard really doesn't have to
handle repeat at all, since the computer knows when keys are pressed and
released and has a timer itself.  Old XT keyboard TSRs allowed you to adjust
the repeat delay and rate by duplicating the key repeat mechanism in the
computer.

Once IBM found that it had a nearly perfect keyboard it, of course, decided
that it had to be almost completely redesigned for the AT.  The keyboard
didn't have to be redesigned- there were enough extra scan-codes for the
AT's 101 key keyboard and the repeat mechanism could simply have been moved
to the BIOS.  But no, they had to redesign everything.  Sigh.

The AT uses a 5-pin DIN and the PS/2 uses a smaller connector with the same
signals:

     1     CLK/CTS (open-collector)
     2     RxD/TxD/RTS (open-collector)
     3     Not connected or Reset
     4     GND
     5     +5V

Now the interface is bi-directional.  When the computer wants to send a byte
to the keyboard, it asserts RTS and releases CTS.  If you're lucky, the
keyboard isn't deciding to transmit at the same time and it responds by
giving 10 clock pulses (at about 10000 baud) on the CLK line.  The computer
shifts a frame out on TxD on rising clock edges.  The frame format is now 1
start bit, 8 data bits and 1 odd parity bit.  The keyboard takes RTS being
held low as the first start bit, and the first data bit should be sent on
TxD after the first clock edge is received.  Yes, now you need a full UART
for the keyboard interface since you have to both transmit and receive and
generate and check parity (but it's still not RS-232- that would have been
too logical).  Why do you need parity checking on a three foot long keyboard
cable?  Because collisions can occur since the lines are so overloaded with
signals with different meanings and parity provides the means for detecting
these collisions.

The AT documentation says that pin 3 is "reserved", so the keyboard has to
provide its own reset.  But on the original AT, pin 3 was still Reset and
IBM's own keyboards at that time needed Reset (original AT keyboards won't
work on some old clones because of this).  Don't ask me... I don't
understand why they did this.

The protocol on the keyboard interface is now much more complicated.  These
bytes are defined:
 
Commands

  ED <byte>                 Set leds depending on byte
                              bit 0 is Scroll lock
                              bit 1 is Num lock
                              bit 2 is Caps lock

  EE                        Echo EE (for testing?)
  F0 <mode>                 Select mode 1, 2 or 3
  F2                        Send keyboard I.D.
  F3 <byte>                 Set repeat delay and rate
                              byte is: 0ddbbaaa
                              delay is (dd+1)*250 msec
                              rate is (8+aaa)*2^bb*4 msec

  F4                        Clear buffer
  F5                        Restore default settings and wait for enable
  F6                        Restore default settings
  FA	                    Acknowledge
  FE                        Error- please retransmit
  FF                        Reset keyboard

Status returns

  00                        Buffer overflow
  AA                        Self-test passed
  F0 <scan-code>            Release code
  FA                        Acknowledge last command
  FD                        Self-test failed
  FC                        Self-test failed
  FE                        Last command in error; re-send
  E0 scan/release code      Extended keys in Mode 2

The computer and keyboard must acknowledge each command and key code with
either FA if there was no error, or FE if the last command/key-code should
be re-sent.  There are three modes of operation for the keyboard, depending
on which scan code assignments you want (these can often be set by a switch
on the back of keyboard, except that if mode 1 is selected from the switch,
the protocol is eliminated an the keyboard works exactly like an original XT
keyboard- newer keyboards only support modes 1 and 3).  In mode 1, the
keyboard gives XT scan-codes.  The keyboard handles the cursor keypad (which
didn't exist on the XT) by simulating pressing or releasing a shift key
(depending on whether shift or num-lock are pressed) and sending codes from
the numeric keypad.  Mode 2 works like mode 1, except that when the keyboard
does the weird stuff with the numeric keypad it prefixes everything with E0
and the release codes are the scan-codes prefixed with F0.  In mode 3, each
key gets a unique code and the release codes work as in mode 2: the release
are the scan-codes prefixed by F0.

When the AT keyboard is first reset it's supposed to send an AA if its
self-test passed or FD or FC if it failed.  But before it does this, it
sends a continual stream of AAs with the parity incorrect.  Once the
computer sends an FE to indicate that there is a parity error, the keyboard
stops sending bad AAs and sends a correct AA or an FD or FC.  This sounds
like someone made a quick fix in the keyboard firmware for mis-matched reset
timing (the keyboard always finishes resetting before the computer so the
computer could miss the AA/FD/FC).


Q) 3.22  Can I fake a keyboard so my computer will boot without it?


[From: jhallen@world.std.com (Joseph H Allen)]

() The IBM Keyboard - how do you use a computer without a keyboard?

Sometimes a PC needs to be set up as a "turn-key" system with no keyboard
for security reasons, or simply because the application doesn't need a
keyboard.  This causes a dead-lock problem when the system is booting: The
BIOS will detect that there is no keyboard and display the message "keyboard
failure - press F1 to continue," and the system becomes stuck.

There is usually a BIOS set-up option for disabling the keyboard test.
Check the manual for your motherboard.  If your BIOS does not have
this option, you're essentially screwed because there's no simple
solution.  You can't wire the DIN to fake the existence of a keyboard
since the BIOS checks for a self-test result code generated by the
keyboard.  You have to implement a small protocol (byte-by-byte
handshaking and ACK/NAK) to simulate a keyboard up to its self test.
There are adaptors available which contain a small microcontroller
programmed to do this.  Another solution is to replace your BIOS with
one which has the keyboard test disable option.  However, you have to
find one which matches your motherboard.


S) 4.0 Storage/Retrieval Devices

Q) 4.1  Why do I lose x Meg on my hard drive?

[From: Mike Long <mike.long@analog.com>]

The problem here is that there are two different measures of hard
drive storage, both called megabytes.  Computer hardware works on the
basis that one megabyte equals 2^20, or 1048576 bytes.  Hard drive
manufacturers, on the other hand, use a megabyte that has 1000000
bytes, because it makes the drive looks larger.  When buying a hard
drive, you should expect to lose almost 5% of what the manufacturer
claims the drive size to be.

The manufacturers are not totally at fault.  The first track of the
drive is used for the partition table and master boot record.  The
amount of data lost here depends on your drive parameters; usually
there are between 32 and 64 sectors (512 bytes/sector) on this first
track, so you lose between 16384 and 32768 bytes that way.

Additional space is taken up by two hidden files on your boot drive.
If you are running MS-DOS, these files are IO.SYS and MSDOS.SYS.  If
you are running PC-DOS, the names are IBMIO.COM and IBMDOS.COM.

[From: ralf@wpi.wpi.edu (Ralph Valentino)]

Many drives these days advertise unformatted capacity.  The actual
formatted capacity may be significantly lower than this as space is
taken up marking tracks, sectors, CRC's, etc.  Exactly how much lower
depends on the the size of the sectors.  For instance, placing 1k
sectors on the disk instead of the usual 512 byte ones may slightly
increase the usable storage space on the disk.  Note, however, that
many OS's insist you stick to the 512 byte sectors so this option is
best left alone.

A large number of drives also do auto-mapping of bad sectors; when a
sector goes bad, it will automatically use a spare it kept aside
during the format.  This is very handy as the OS never needs to deal
with the problem and some OS's, like DOS, will mark a whole cluster
bad when a single sector goes bad.  These spare sectors, as many as
one per track, remain hidden from the OS but still take up space on
your hard drive.

When you get to drives larger than 1.0 gig (SCSI), many host adapter
BIOS's can not deal with this as the BIOS was never designed to handle
more than 1024 cylinders, 64 heads, and 32 sectors per track. (1024 *
64 * 32 * 512bytes/sec = 1.0 gig).  Luckily, some OS's (like OS/2)
ignore the BIOS all together and read the actual geometry from the
disk itself.  If, however, you're not using such an OS and you notice
that you only have 1.0 gig available, you may want to check with the
manufacturer of your SCSI host adapter to see if a newer BIOS is
available.

Q) 4.2  *Should I get an IDE/floppy/SCSI/parallel port tape drive?
Q) 4.3  I have two floppies. Can I add a floppy based tape drive?
 
[From: herbst@techunix.technion.ac.il (Herbst OMR)]

It depends. On all modern tape drives: yes. Some old tape drives
cannot do this (my old Jumbo). If you have one of these, you will have
to buy either a 4-floppy controller or a dedicated tape controller.

Q) 4.4  How fast is a tape drive? Will a dedicated controller improve this?

[From: herbst@techunix.technion.ac.il (Herbst OMR)]

The tape connected through a floppy interface is limited to the floppy
speed.  On ATs 500Kbit/S. On old XT 250Kbit/S. With card support for
2.88MB floppy, 1Mbit/S. Many of the newer cards support this transfer
rate.
 
If the card operate at 500Kbit/S, a dedicated controller card will
speed up the tape by a factor of two.  In many cases, those cards do
hardware compression, helping even more.

Q) 4.5  What is QIC80, QIC40?
 
[From: herbst@techunix.technion.ac.il (Herbst OMR)]

QIC stands for Quarter-Inch Cartridge. QIC80 is the standard for 80MB
tapes, QIC40 for 40MB tapes. Both standard allows for extended length
cassettes of 300ft which gives 120MB and 60MB respectively.

Q) 4.6  How come I can't fit as much stuff on my tape drive as they claim?

Most tape drives these days advertise capacity with an expected
compression ratio of 2:1.  If you are backing up compressed files
(.Z,.ZIP, .ARC, .JPEG, and so forth) then the drive's own compression
scheme will not be as effective.  For these cases, the actual capacity
of the tape will be closer to the "uncompressed" capacity.

A table from herbst@techunix.technion.ac.il (Herbst OMR) shows:

  stated capacity     standard        tape length         # tracks
 
  80MB                QIC40           200ft (normal)      15
  120MB               QIC40           300ft (extended)    15
  160MB (rarely)      QIC80           200ft               28
  250MB               QIC80           300ft               28
 
  For all the recording density is 12500 ftpi; max tape speed is 90 ips.

A second reason is that some tapes assume you will be taking full
advantage of their "streamers".  Streaming collects a number of tape
blocks and writes them all at once, preventing the need for backing up
the tape after each block.  This positions the blocks closer together
on the tape.  If your backup program is slow, some streamers won't be
quite as effective.  If you hear the tape drive motor backing up the
tape alot on writes, this could be the case.

Q) 4.7  Are Colorado/Conner/Archive/... tapes compatible with each other?

[From: herbst@techunix.technion.ac.il (Herbst OMR)] 

If you use the same software: Yes. If you want to use different
software, then turn compression off. Compression done in software on
those drives is not compatible.

Q) 4.8  How does the drive/software know how long the tape is?

[From: herbst@techunix.technion.ac.il (Herbst OMR)]
 
The magnetic tape has holes in it. Inside the cassette enclosure there
is a small mirror. The drive sends an IR beam through it. Near the end
of tape the drive receives it. If the IR receiver is dusted, the drive
may 'reel off' the cassette.

Q) 4.9  What are all those QICs?

[From: herbst@techunix.technion.ac.il (Herbst OMR)]
 
(Thanks to Karl-Peter Huestegge and Jan Christiaan van Winkel)
QIC-11 is not an Industry Standard and there exist some incompatible
versions.
 
 Standard      Capacity      Tracks   Speed  Rec-density Flux-Trans Cartridges
 ----------------------------------------------------------------------------
 QIC-11     15/30MB (300ft)     4/9   90ips
            20/40MB (450ft)     4/9   90ips               6400ftpi  DC300XL
                                                         10000ftpi  DC300XLP
            27/60MB (600ft)     4/9   90ips              10000ftpi  DC600A
 
 QIC-24     45MB (450ft/137m)    9    90ips    8000bpi   10000ftpi
            55MB (555ft/169m)    9    90ips    8000bpi   10000ftpi
            60MB (600ft/183m)    9    90ips    8000bpi   10000ftpi  DC600A
 
 QIC-120   125MB (600ft/183m)    15   72ips   10000bpi   12500ftpi  DC600A
 
 QIC-150   155MB (600ft/183m)    18   72ips   10000bpi   12500ftpi  DC600XTD
                                                                    DC6150
 QIC-150   250MB (1000ft/305m)   18   72ips   10000bpi   12500ftpi
 
 QIC-320   320MB (600ft/183m)    26   72ips   16000bpi   20000ftpi  DC6320
 
 QIC-525   525MB (1000ft/305m)   26   72ips   16000bpi   20000ftpi  DC6525
 
* QIC-1000  1000MB (760ft)
 
* QIC-2GB
 
* QIC-10GB
 
Q) 4.10  Which QICs are read/write compatible?

[From: herbst@techunix.technion.ac.il (Herbst OMR)]

 The left column should be read: "Tape drives designed for the QIC-???
 standard *should* be able to read/write the following Tape formats:"
 
 TAPE-DRIVES     |                     Tape - Formats                      |
 designed for:   | QIC-11 | QIC-24 | QIC-120 | QIC-150 | QIC-320 | QIC-525 |
 ----------------|--------|--------|---------|---------|---------|---------|
 QIC-11          |  R  W  |        |         |         |         |         |
 QIC-24          |  R  W  | R   W  |  R      |         |         |         |
 QIC-120         |  R  -  | R   -  |  R   W  |  R      |         |         |
 QIC-150         |  R  -  | R   -  |  R   W  |  R   W  |         |         |
 QIC-320         |  R  -  | R   -  |  R   W  |  R   W  |  R   W  |  ?   ?  |
 QIC-525         |  R     | R      |  R   W  |  R   W  |  R   W  |  R   W  |
 ---------------------------------------------------------------------------

===============
Ralph Valentino   (ralf@chpc.org)  (ralf@wpi.wpi.edu)
Hardware Engineer,  Worcester  Polytechnic  Institute
Center for High Performance Computing, Marlborough MA

From ankh.iia.org!babbage.ece.uc.edu!news.kei.com!MathWorks.Com!noc.near.net!chpc.chpc.org!chpc.chpc.org!not-for-mail Sun Aug 14 17:59:18 1994
Path: ankh.iia.org!babbage.ece.uc.edu!news.kei.com!MathWorks.Com!noc.near.net!chpc.chpc.org!chpc.chpc.org!not-for-mail
From: ralf@chpc.org (Ralph Valentino)
Newsgroups: comp.sys.ibm.pc.hardware.video,comp.sys.ibm.pc.hardware.comm,comp.sys.ibm.pc.hardware.storage,comp.sys.ibm.pc.hardware.cd-rom,comp.sys.ibm.pc.hardware.systems,comp.sys.ibm.pc.hardware.networking,comp.sys.ibm.pc.hardware.chips,comp.sys.ibm.pc.hardware.misc,comp.answers,news.answers
Subject: comp.sys.ibm.pc.hardware.* Frequently Asked Questions (FAQ) Part 3/5
Followup-To: comp.sys.ibm.pc.hardware.misc
Date: 12 Aug 1994 02:07:50 -0400
Organization: Center For High Performance Computing
Lines: 2679
Sender: ralf@chpc.chpc.org
Approved: news-answers-request@MIT.EDU
Distribution: world
Expires: 11 Sep 1994 00:00:00 GMT
Message-ID: <32f3jm$8sb@chpc.chpc.org>
Reply-To: ralf@wpi.edu
NNTP-Posting-Host: localhost.chpc.org
Summary: This is a monthly posting containing a list of Frequently
	 Asked Questions (and their answers) pertaining to hardware
	 and IBM PC clones.  It should be read by anyone who wishes
	 to post to any group in the comp.sys.ibm.pc.hardware.*
	 hierarchy.
Xref: ankh.iia.org comp.sys.ibm.pc.hardware.video:9601 comp.sys.ibm.pc.hardware.comm:3134 comp.sys.ibm.pc.hardware.storage:7352 comp.sys.ibm.pc.hardware.cd-rom:4234 comp.sys.ibm.pc.hardware.systems:4215 comp.sys.ibm.pc.hardware.networking:2184 comp.sys.ibm.pc.hardware.chips:7713 comp.sys.ibm.pc.hardware.misc:7817 comp.answers:3110 news.answers:9227

Archive-name: pc-hardware-faq/part3
Last-modified: 1994/08/10
Version: 1.7


Q) 4.11  What is the CMOS/jumper setting for my hard drive?

[From: Carsten Grammes (cagr@rz.uni-sb.de)]

		    Configuration of IDE Harddisks
		    ==============================


last update: 24 March 1994

collected by Carsten Grammes (cagr@rz.uni-sb.de)
and published on comp.sys.ibm.pc.hardware as part of the FAQ.



!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
There is explicitly NO WARRANTY that the given settings are correct or
harmless. (I only collect, I do not check for myself!!!). There is
always the possibility that the settings may destroy your hardware!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


Since I hope however that only well-minded people undergo the effort of
posting their settings the chance of applicability exists. If you should
agree or disagree with some setting, let me know immediately in order
to update the list.

If you possess a HD not mentioned here of which you know BIOS and/or
jumper settings, please mail them to me for the next update of the list!

Only IDE (AT-Bus) Harddisks will be accounted for.  If not specified the
Landing Zone should be set equal to the number of cylinders. If not
specified the 'Write Precompensation' should be set 65535. (There are
BIOSes that don't even ask for it).  On most IDE disks these values are
dummies, relicts from old MFM times.

The capacity given here is sometimes in Megabytes (1000000 bytes) and
sometimes in MB (1048576 bytes). Don't worry! The only right way to calculate
the capacity is
    cyl * heads * sec/tr * 512 
which gives the capacity in bytes!  Dividing by 1000000 or 1048576 gives
the capacity in Megabytes or MB respectively.

If you get problems when installing 2 HD's with correct BIOS and jumper
settings, try to swap drive 1 and 2, often that helps.

Please don't flame me because of the 'layout' of the list. Since the
available information is so strongly varying I often only pack _YOUR_
mail to me into the list. If someone feels encouraged to improve this,
I would be glad to receive a 'lifted' version. But there should be all
info contained!

Since the list is rather long, I give here a summary of all drives
described therein.

************* ALPS Alps alps
DR311C

************* CDC Cdc cdc
BJ7D5A	 94155-48   94335-100  94166-141   94171-300  736 SABRE
BJ7D5A	 94295-51   94355-55   94166-182   94171-344  850 SABRE
BJ7D5A	 94155-57   94355-100  94186-383   94181-574  1230 SABRE
94155-21 94155-67   94155-135  94186-383H  94208-51
94155-25 94155-77   94205-77   94186-442   94211-91
94155-28 94155-85   94355-150  94216-106   94221-190
94155-36 94155-86   94335-150  94356-200   94351-172
94155-38 94205-51   94156-48   94161-86    368 SABRE
94335-55 94156-67   94166-101  94161-121   500 SABRE

************* CONNER Conner conner
CP342	CP2034	 CP2084   CP3044  CP3104  CP3204  CP30084
CP344	CP2044	 CP3000   CP2124  CP3111  CP3204F CP30104
CP2024	CP2064	 CP3024   CP3184  CP3114  CP30064 CP30084E

CP30174E  CP30174E  CP3304  CP3544
CP30204   CP30204   CP3364  CP3554
CP30254   CP30254   CP3504  CP30101

************* FUJITSU Fujitsu fujitsu
M2611T	M2612ET  M2613ET  M2614ET  M2618T  M2622T  M2623T  M2624T

************* HEWLETT PACKARD Hewlett Packard hewlett packard HP Hp hp
C2233

************* IBM Ibm ibm
WDA-L160   WDA-L42   IBM 85 MB IDE (number not known)

************* JVC Jvc jvc
JD-E2085M

************* KALOK Kalok kalok
KL3100 KL3120

************* MAXTOR Maxtor maxtor
LXT-200A  2585A  7120A
LXT-213A  7040A  7131AT
LXT-340A  7060A  7213A
LXT437A   7080A  7245A
LXT535A

************* MICROPOLIS Micropolis micropolis
2105A	  2112A

************* MICROSCIENCE Microscience microscience
7100-00  8040-00  7070-20  7100-00  7100-20  8040

************* MINISCRIBE Miniscribe miniscribe
8225AT	8051AT	8450AT

************* NEC Nec nec
D3735  D3755  D3756  D3741

************* QUANTUM Quantum quantum
40AT	 LPS52AT      ELS42AT
80AT	 LPS80AT      ELS85AT
120AT	 LPS105AT     ELS127AT
170AT	 LPS120AT     ELS170AT
210AT	 LPS170AT     LPS540A
425AT	 LPS240AT

************* RODIME Rodime rodime
RO3058A  RO3088A  RO3095A  RO3128A  RO3135A  RO3059A  RO3089A
RO3129A  RO3139A  RO3209A  RO3259A

************* SAMSUNG Samsung samsung
SHD-3101A  SHD-3061A  SHD-3062A

************* SEAGATE Seagate seagate
ST1057a     ST1144a	ST138a	    ST274a	ST3283a
ST1090a     ST1156a	ST1400a     ST280a	ST351ax
ST1102a     ST1162a	ST1401a     ST3051a	ST9051a
ST1111a     ST1186a	ST1480a     ST3096a	ST9077a
ST1126a     ST1201a	ST157a	    ST3120a	ST9096a
ST1133a     ST1239a	ST2274a     ST3144a	ST9144a
ST3243A     ST125a	ST2383a     ST325ax
ST351AX
ST9235A     (maybe others)

************* TEAC Teac teac
SD-3105

************* TOSHIBA Toshiba toshiba
MK1122FC  MK2024FC  MK2124FC  MK2224FC	MK234FCH  MK234FCF

************* WESTERN DIGITAL Western Digital western digital
WDAC140  WDAC280  WDAC1170  WDAC2120  WDAC2170	WDAC2200  WDAC2250
WDAC2340 WDAC2420 WD93044-A WDAH260   WDAH280	WDAP4200
WD93048A



And here it comes...


************* ALPS Alps alps *************

Manufacturer: ALPS ELECTRIC Co.

BIOS settings:
Model   Heads  Cylinders  Sectors  L-Zone Size
DR311C   14      868        17      868   105 MB

(Real geometry of drive:
   2108 cyl.  2 heads  49 sectors/track
   32k internal cache)

Jumpers:
  C/D
 -ACT
 -DSP
 -HSP
  MS3
  SYNC
  DC
  MS0
  MS1
  MS2

Master drive & no slaves present: jumpers on C/D and -ACT.
No other jumpers installed, function unknown.


***************************   C D C ***********************************

I have the feeling that not all of these are IDE...

-------------------------------------------------------------------------------
MODEL	 ST-506 	CAP   CYL  H  RWC  WPC ENC  RATE ACCESS  SPT COMMENTS
-------------------------------------------------------------------------------
BJ7D5A  77731614 5.25FH  23   670  4  375  375 M    5             17
BJ7D5A  77731608 5.25FH  29   670  5  375  375 M    5             17
BJ7D5A  77731613              733  5  -    -        5             17
94155-21 WREN-1 5.25FH   21   697  3  698  698 M    5    28 MS    17
94155-25                 24   697  4  698  128 M    5             17
94155-28                 24   697  4  698  128 M    5             17
94155-36 WREN-1 5.25FH   36   697  5  698  698 M    5    28 MS    17
94155-38                 31   733  5  734  128 M    5             17
94155-48 WREN-2 5.25FH   40   925  5  926  926 M    5    28 MS    17
94295-51 WREN-2 5.25FH   43   989  5  990  990 M    5    28 MS    17
94155-57 WREN-2 5.25FH   48   925  6  926  926 M    5    28 MS    17
94155-67 WREN-2 5.25FH   56   925  7  926  926 M    5    28 MS    17
94155-77 WREN-2          64   925  8  926  926 M    5             17
94155-85 WREN-2 5.25FH   71  1024  8   -    -  M    5    28 MS    17
94155-86 WREN-2 5.25FH   72   925  9  926  926 M    5    28 MS    17
94205-51       5.25HH    43   989  5  990  128 M    5    32 MS    17
94335-55        3.5"     46  -     5   -    -  M    5    25 MS    17
94335-100       3.5"     83  -     9   -    -  M    5    25 MS    17
94355-55   SWIFT-2 3.5"  46  -     5   -    -  M    5    16.5 MS  17
94355-100       3.5"     83  -     9   -    -  M    5    16.5 MS  17
    ST-506 RLL
94155-135 WREN-2 5.25HH  115  960  9   -    -  R    7.5  28 MS    26
94205-77  WREN-2 5.25HH  63   989  5   -    -  R    7.5  28 MS    26
94355-150        3.5"    128 -     9   -    -  R    7.5  16.5 MS  26
94335-150        3.5"    128 -     9   -    -  R    7.5  25 MS    26
    ESDI
94156-48   WREN-2        40   925  5  926  926 N    5    28 MS
94156-67   WREN-2        56   925  7  926  926 N    5
94156-86   WREN-2        72   925  9  926  926 N    5
94166-101  WREN-3 5.25FH 86   969  5  970  970 N    10   16.5 MS
94166-141  WREN-3 5.25FH 121  969  7  970  970 N    10   16.5 MS
94166-182  WREN-3 5.25FH 155  969  9  970  970 N    10   16.5 MS
94186-383  WREN V 5.25FH 383 1412 13   -    -  R/N  10   8.3 MS
94186-383H WREN V 5.25FH 383 1224 15   -    -  R/N  10   14.5 MS
94186-442  WREN V 5.25FH 442 1412 15   -    -  R/N  10   16 MS
94216-106  WREN-3 5.25FH 91   969  -   -    -  N    10   16.5 MS
94356-200  SWIFT 3 3.5"  172 -     9   -    -  R/N  10   16.5 MS
WREN III          5.25HH 106  969  5   -    -  R/N  10   18 MS
    SCSI
94161-86   WREN-3 5.25FH 86   969  -   -    -            16.5 MS
94161-121  WREN-3 5.25FH 121  969  -   -    -            16.5 MS
94171-300  WREN-4 5.25FH 300 1365  9   -    -  R         16.5 MS
94171-344  WREN V 5.25FH 344 1549  9   -    -  Z    9-15 17.5 MS
94181-574  WREN V 5.25FH 574 1549 15   -    -  Z    9-15 16 MS
94208-51
94211-91   WREN-3 5.25FH 91   969  -   -    -            16.5 MS
94221-190  WREN V 5.25HH 190 1547  5   -    -  R    10-15 8.3 MS
94351-172  SWIFT 4 3.5"  172 -     9   -    -       10   16.5MS
WREN III         5.25HH  106  969  5   -    -  R/N  10   18 MS
    SMD
368 SABRE  8"            368 -    10   -    -       1.8  18 MS
500 SABRE  8"            500 -    10   -    -       2.4  18 MS
736 SABRE  8"            741 -    15   -    -       1.8  16 MS
850 SABRE  8"            851 -    15   -    -       2.4  16 MS
1230 SABRE 8"           1236 1635 15   -    -       2.4
-------------------------------------------------------------------------------

    CAP   = CAPACITY IN FORMATTED MEGABYTES
    CYL   = MAXIMUM NUMBER OF CYLINDER
    H     = NUMBER OF DATA HEADS
    RWC   = START REDUCED WRITE CURRENT
    WPC   = START WRITE PRECOMP
    ENC   = ENCODING METHOD R=RLL, M=MFM,Z=ZBR
    RATE  = TRANSFER RATE IN MEGABITS/SEC
    ACCESS= AVERAGE ACCESS TIME
    SPT   = SECTORS/TRACK X 512 bytes
    FH    = FULL HIGH FORM FACTOR
    HH    = HALF HIGH FORM FACTOR
    R     = RLL (run length limited)
    N     = NRZ (non return to zero)
    M     = MFM (modified frequency modulation)
    SA    = STAND ALONE
    Z     = ZBR

Jumpers are not know (yet).


************************** CONNER Conner conner **************************

Conner drives are low level formatted at the factory. It is only necessary to r
un SETUP, FDISK and DOS FORMAT.
          
Model     Hds  Cyls  Sec    Pcomp  L-Zone    Type    Table  LED
CP342     4    805   26       0    805        17       n/a  A
CP344     4    805   26       0    805        17       1    A
CP2024    2    653   32       0    653         2       3    n/a
CP2034    2    823   38       0    823       *UT       3    n/a
CP2044    4    552   38       0    552        17       3    n/a
CP2064    4    823   38       0    823       *UT       3    n/a
CP2084    8    548   38       0    548       *UT       3    n/a  
CP3000    2   1047   40       0   1047        17       1    A
CP3024    2    636   33       0    636         2       1    A
CP3044    1   1047   40       0   1047        17       1    A
          5    980   17   (also reported)
CP2124    8    560   53       0    560       *UT       3    n/a
CP3184    6    832   33       0    832       *UT       1    A
CP3104    8    776   33       0    776       *UT       1    A
CP3111    8    833   33       0    833       *UT       1    A(?)
CP3114    8    832   33       0    832       *UT       1    A
CP3204    16   683   38       0    683       *UT       2    B
CP3204F   16   683   38       0    683       *UT       3    B
CP30064   4    762   39       0    762       *UT       2    B
CP30084   8    526   39       0    526       *UT       2    B
CP30104   8    762   39       0    762       *UT       2    B
CP30084E  4    903   46       0    903       *UT       4    C
CP30174E  8    903   46       0    903       *UT       4    C
CP30204   16   683   38       0    683       *UT       4    C
CP30254   see below
CP3304    16   659   63       0    659       *UT       4    D 
CP3364    16   702   63       0    702       *UT       4    C
CP3504    16   987   63       0    987       *UT       4    D
CP3544    16   1024  63       0    1024      *UT       4    C
CP3554    16   1054  63       0    1054      *UT       3    B

Table 1 jumper settings: 
     Single drive = Jumper ACT and C/D 
     Master drive = Jumper ACT, C/D and DSP.
     Slave drive = No jumpers installed.

Table 2 jumper settings:
     Single drive = Jumper E2
     Master drive = Jumper E1 & E2
     Slave drive = No jumpers installed.

Table 3 jumper settings:
     Single Drive = Jumper C/D
     Master Drive = Jumper C/D and DSP
     Slave Drive = No jumpers installed

Table 4 jumper settings:
     Single and Master drive = Jumper C/D
     Slave drive = no jumper




ALL CONNER 20 MBYTE DRIVES USE DRIVE TYPE 2. ALL CONNER 40 MBYTE DRIVES USE DRI
VE TYPE 17.                                        * 

UT = Universal translate. Select a drive type that is close to, but does not ex
ceed the megabyte capacity of the drive. The drive will translate to the megaby
te capacity you have selected.

 LED
A: J-4         B: J-1         C: J-5         D: J-3
Pin 1 = +      Pin 3 = +      Pin 3 = +      Pin 3 = +
Pin 2 = -      Pin 4 = -      Pin 4 = -      Pin 4 = -

Conner drives are low level formatted at the factory. It is only necessary
to run SETUP, FDISK, and DOS FORMAT.

Comment concerning CP3000 jumpers:

   According to your list, all Conners should be 2 or 3 jumpers only.
That's why I'm puzzled with the 4-jumper Conner CP-3000.
In addition to the common jumpers present in
Conner - C/D, DSP & ACT, there is an extra one: HSP
By trial and error, HSP seems to follow DSP setting.


> When I installed a Conner CP3204F (203 MB) as master and a WD Caviar 2200
> (203 MB) as slave, both with and without the "CP" jumper, the Caviar had
> seemingly normal behaviour. However, when doing writes to the Caviar, once
> in a while it would overwrite directories etc. Using FASTBACK was almost
> impossible.
> 
> The workaround is to install the Caviar as the master, and the Conner
> as the slave.

and:
information: I am slaving a Conner CP3000 40Meg to a Western Digital
Caviar 2200 212 Meg.

the results: I first found out that pin 1 on the CP3000 was LABELED
INCORRECTLY on the PC board....had to flip the IDE cable (which made the
cable install much more cleanly- no flips....shoulda been my first clue
that something was not correct, oh well)

next: I had to DOS-format the CP3000 ALONE on the PC system before it
wanted to work with the WD caviar.... weird
also: the WD Caviar is partitioned: C:\ was the first 100 Meg and D:\ was
the second 100 Meg.  After the CMOS was correctly configured and the
drives brought online, the PC AUTOMATICALLY assigned the drives as thus:
C:\ first 100 Meg partition on the WD
D:\ 40 Meg Conner
E:\ second 100 Meg partition on the WD
even FDISK reports the above.  


Conner CP 30254

Capacity: 250 MB
Dimensions: 3,5 inch, lowprofile (1 inch)
IDE interface
              		 Cylinders Heads Sectors

Physical specs.:         1985      4     62
Logical specs.:		 895       10    55

seek time 12 ms
Rotation speed 4542 rpm

jumpers  	C/D
1 drive master	Y
2 drive master	Y
2 drive slave	N/Y


----

Subject: Re: Conner CP 30254

I tried several combination and even called Conner for info on
configuring two Conner drives as master (301??, a 300+ M Connder
drive) and slave (30254).  The jumpers that worked are:

		Pins 	Jumpers
Master		1-2	   Y 	 (factory setting)
	        3-4	   Y	 (factory setting)

Slave		1-2	   N
		3-4	   Y	 (factory setting)

So the C/D should mape to Y/N instead of N/Y in the table.
--
Some notes made whilst configuring a pair of Conner IDE drives
for Master/Slave operation from Hyundai Super-LT6 Laptop 386sx-20.

Final Working Configuration

Drive 1:	CP3000	40 Mb	Type 17
977 cyl 5 hds	17 sec/trk	Pre 300 LZ 977

Verified configuration as per Grammes' list. HSP does need to
follow DSP (empirically) - failure to do so produced behaviour
such as LCD screen display scrambling on ROM boot.

Single, Master and Slave configurations all checked out.

Drive 2:  CFA170A 170 Mb  Unknown type
332 cyl 16 hds	63 sec/trk	Pre --- LZ ---

Did not appear on Grammes' list. Successful configuration resulted
close to that shown as Table 3 for Conner drives, as follows:

	Single		2 links 	(not C)/D and (not A)/(?)
	Master		1 link		(not C)/D
	Slave		0 links

One link is listed here as (not A)/(?) due to a hole being drilled
through the (?) part of the silk screening ...

The drives worked together as either slave or master ...
--
Connor CP30101
760 cyl, 8 hds, Precomp -1, Landing 760, Sec/Track 39, ECC 7 Capacity 121.41M


Model CP342 disk (40 Meg IDE drive)
  Single Drive: E5, E7 jumpers IN
  Master Drive: E6, E7 jumpers IN
  Slave Drive:  E7 jumper IN

In addition, this is an old disk drive.  It was factory configured to
use 3:1 interleave.  This can cause timing problems with newer disk
drives that are configured for 1:1 interleave when using the same IDE
controller.  The CONNER tech support person suggested I only use the
CONNER drive as a SLAVE with the newer disk as the MASTER.

This configuration (MAXTOR 7345A as MASTER and CONNER CP342 as SLAVE)
has now been in use for over a week and seems to be working fine.


************************  FUJITSU Fujitsu fujitsu  ***************************

DETAILS OF FUJITSU DRIVES M261xT (Standard)

                   M2614ET     M2613ET     M2612ET     M2611T

Heads (physical)       8           6           4           2
Cyl (physical)      1334        1334        1334        1334
Sec/trk               33          33          33          33
Speed (rpm)         3490        3490        3490        3490
Capacity           180MB       135MB        90MB        45MB


              +-----------------------------------------------+
              |                                               |
              +--+                                            |
        PSU   |  |      CNH-2                                 |
              +--+          1                                 |
            1 |  |          .                    LED          |
              |  | CNH-1    9      CNH-3      Connector       |
              |  |   1           6..1            o o          |
      40-way  |  |   .                           | |          |
        IDE   |  |   .                                        |
              |  |   .                                        |
              |  |  12                                        |
              +--+                                            |
              +-----------------------------------------------+



                 Pin        Function
                 Position

                 *  1- 2    Active mode
                    2- 3    Slave present mode
                    4- 5    Pin 27=IOCHRDY
CNH-1 JUMPERS    *  5- 6    Pin 27=RESERVED
                    7- 8    2 drive system
                 *  8- 9    1 drive system
                   10-11    Pin 29=IRQ14 : Pin 31=RESERVED
                 * 11-12    Pin 31=IRQ14 : Pin 29=RESERVED


                 Pin        Function
                 Position

                    1- 2    SLAVE drive mode
CNH-2 JUMPERS    *  4- 5    MASTER drive mode
                    7- 8    ECC 4 bytes
                 *  8- 9    ECC 7 bytes


                 Pin        Function
                 Position

                    1- 2    Write protect enabled
CNH-3 JUMPERS    *  2- 3    Write protect disabled
                    4- 5 -6 Reserved

Key:  * (I guess!) marks factory default setting for jumper


BIOS SETTINGS

BIOS setting for the M2614ET in my system is 667 cylinders, 33 sectors
and 16 heads.

> I was trying to set my IDE drive in the subject above to a slave drive for
> A Conner 170MB drive and contacting the support company gave me this answer (which works). The factory default on SW2 is On Off Off Off Off Off (1-6). This sets the drive to be a single drive. Setting SW2 to Off On On Off Off Off makes it a slave drive. SW1 has been set to On Off Off On (1-4) all along.



MODEL      CYLINDERS   HEADS    SECTORS   CAPACITY (Million bytes)

M2622T      1013        10        63         326.75
M2623T      1002        13        63         420.16
M2624T      995         16        63         513.51


There are 6 switches on the switch block on these drives.  Only 4 of 
them have a use that I am aware of (from my M2624T manual):

Master/Slave        Master (*)      SW1-5 OFF
                    Slave           SW1-5 ON
ECC bytes           4 bytes (*)     SW1-4 OFF
                    7 bytes         SW1-4 ON
Write Protect       Disabled (*)    SW1-3 OFF
                    Enabled         SW1-3 ON
IO Channel Ready    Disabled (*)    SW1-1 OFF
                    Enabled         SW1-1 ON

I have no idea about the function of SW1-2 and SW1-6.  The values 
listed with a (*) are the factory default settings.


M2618T	202MB	Cyl/hd/spt  718 12 48


*********************	Hewlett Packard   ****************************
HEWLETT PACKARD Hewlett Packard hewlett packard HP Hp hp

C2233	227 MB	Cyl/hd/spt  733 12 53


*********************	IBM Ibm ibm   ****************************

WDA-L160    163 MB	Cyl/hd/spt  984 10 34
WDA-L42	    42MB	Cyl/hd/spt  977 5 17

Jumpers for IBM WDA-L160:

Fit JP2 for Master or single drive

Remove JP2 and fit JP3 for Slave

JP1 appears to be always fitted.

Functions of other jumpers unknown at present.

Position of jumpers:

		-----------------------------------------
		|          Drive Mechanism              |
		|					|
		-----------------------------------------
				PCB		. . . . 
					        . . . .

					JP      4 3 2 1	


Also:

IBM 85 M IDE (number not known)

10 Heads	984 Cylinders		17 Sectors	0 WPC	984 LZ

Patches as for L160 above


*********************	JVC Jvc jvc   ****************************

JD-E2085M   79 MB	Cyl/hd/spt  973 4 43


***********************    KALOK Kalok kalok	***************************

KALOK	KL3100	  105 MB
BIOS:	cyl 979     heads 6	sectors 35

KALOK   KL3120    120 MB
BIOS:	 Cyl 981     heads 6     sectors 40

The following jumper settings have been reported for KL3100 but are probably
also valid for other Kalok drives.

Single HD:
o o o o o

o o o o-o    <-- same row as pin 1 of the IDE connector.

Master (disk 1):
o o o o o
    |
o o o o o

Slave:
o o o o o
      |
o o o o o

These 5 pairs of pins are at the righthand side of the disk.



************************   MAXTOR Maxtor maxtor   ***************************

Model           Cyls    Heads   Sectors Precomp Landing Zone
----------	-----	-----	-------	-------	------------
LXT-200A	816	15	32	0	816
LXT-213A	683	16	38	0	683
LXT-340A	654	16	63	0	654
LXT437A		842	16	63	0	842
LXT535A		1036	16	63	0	1024

Jumpers are as follows:

The bottom of the drive looks like this (well, sort of):

|        o o 1-2             |
|        o o 3-4             |
|        o o 5-6             |
|        o o 7-8             |
|        o o 9-10            |
|                            |
+[POWER] [IDE CONNECTOR]-----+

				Single drive	  Dual Drive System
Pin numbers	Jumper		System		Master		Slave
-----------	------		------------	------		-----
1-2		Slave Drive	remove		remove		install
3-4		Activity LED	optional	optional	optional
5-6		Slave Present	remove		remove		optional
7-8		Master Drive	remove		install		remove
9-10		Sync Spindle	remove (n/a)	optional*	remove

* only one drive (the master) in an array should have this jumper installed.


		Hd    Cyl   spt
Maxtor 2585A	10    981   17

Maxtor 7060A    16    467   17     62,0 J14 closed, J13 closed
Maxtor 7060A     7   1024   17     59,5 J14 open,   J13 open
Maxtor 7060A     4    762   39     58,0 J14 closed, J13 open
Maxtor 7060A     8    925   17     57,9 J14 open,   J13 closed

Maxtor 7120A    16    936   17    124,3 J14 closed, J13 closed
Maxtor 7120A    14   1024   17    119,0 j14 open,   J13 open
Maxtor 7120A     8    762   39    116,0 J14 closed, J13 open
Maxtor 7120A    15    900   17    112,0 J14 open,   J13 closed
Maxtor 7120A     8    824   33    106,2 J14

Jumpers for the above 2 drives:

                  J11  I/O-channel ready ( open: disabled; close: enabled )
                  J13  see above
                  J14  see above
                  J15  operation-status ( open: normal; close: factory )
       J J J J J            
       2 1 1 1 1
       0 9 8 7 6

Power  data-cable

J16: Idle mode latch ( open: disabled; close: enabled )
J17: drive model ( open: 7060A; close 7120A )
J18: ECC Bytes ( open: 7 bytes; close: 4 bytes )

Master/Slave: drive is master and alone    : J20 closed, J19 closed
              drive is master of two drives: J20 closed, J19 open
              drive is slave of two drives : J20 open  , J19 closed


Maxtor 7213A

Default (power-up) AT BIOS Translation Parameters (others possible)
Cyl   Hds  SpT  MBytes
683   16   38   212

There are two sets of jumpers. A set of 5 and a set of
4. With the power and IDE connector toward you, the set of 5 is
numbered (left to right) J16 - J20  , and the set of 4 is numbered
(bottom to top) J22-J25. 

The only jumper of normal interest is J20. Jumper it for only
drive in a single drive system, or master drive in a dual drive
system.
 
Remove the jumper J20 for slave drive in a dual drive system. 

J19 is a dummy and may be used to store the spare shunt if the 
drive is configured for a slave mode.

Jumpers J17, J18, J24, J25 are factory reserved. Abnormal operation
may occur if jumpered.

Jumper 22 is sync spindle enabled/disabled  (open=disabled)
Jumper 23 is sync slave/master              (open=slave)
Jumper 16 is I/O Channel Ready              (open=disabled)


Maxtor 7245A (245Mb IDE; self-parking; Universal Translate):
Drive type : User defineable
Cyl    Hds    WPC    LZ     S/T
967    16     0      0      31      (WPC and LZ optional)

Master(2):  J20 closed
Slave(2):   J20 open (use J19 for shunt storage)
Single:     J20 closed


 
 Basic Specifications                                       
 -------------------------------------------------------------------
         Formated              Data          Sect.         Average
 Model   Capacity   Cylinders  Heads  Disks  Track  Cache  Seek Time
 7080A   82.2 MB    1.170      4      2      36     32k    17ms  
 7040A   41.1 MB    1.170      2      1      36     32k    17ms  
 
 AT BIOS Translation Parameters
 ---------------------------------+---------------------------------
 Model  Cyls  Heads  Spt   MB     |  Model   Cyls  Heads  Spt   MB
 7080A  1039    9    18    82.1   |  7040A   524     4    40    40.9 
         981   10    17    81.4   |          981     4    17    40.7 
         832    6    33    80.4   |          977     5    17    40.5  
         497   10    33    80.0   |                                 
        1024    9    17    76.5   |                                 
 
 Technical Notes:
 ------------------------------------------------------------------------
 * The WPC and Landing Zone BIOS entieres do not need a specific number 
   for proper operation. Maxtor AT interface hard drives will ignore and
   override any numbers programmed.             

 * Drive is low-level formated with 1:1 interleave at factory, with any 
   defects retired to a dedicated non-destructive zone.
 
 * The drive's on-board controller will auto-translate every cylinder, 
   head, and SPT combination listed in the parameters table. Therefore, 
   configuration jumpers J13 and J14 are not required for most AT BIOS 
   setup applications.

 * The 7080A is shipped with J17-J20 jumered and the 7040A is shipped 
   with J18-J20 jumpered to operate as single AT IDE drives. J20 and J19 
   control master/slave operation.
 
 7080A / 7040A Jumper Designation
 ------------------------------------------------------------------------
 Jumper   |               21111    1111  |  J3 1 +12V DC      J7 1 +5V
 Position |               09876    5431  |     2 +12V Ground     2 +12V
          |                              |     3 +5V Ground      3 Ground
 Pins     +[4321]--[1            ]--[321]+     4 +5V DC
         J3 Power     Data Cable   J7 Power

 J20 J19  Master/Slave Select    (*) Single Drive   closed, closed
                                     Master (Dual)  closed, open
                                     Slave (Dual)   open, closed
 J18      ECC Bytes              (*) closed 4 Bytes / open 7 Bytes
 J17      Drive Model                open 7040A / closed 7080A
 J16      Idle Mode Latch        (*) open disabled / closed enabled
 J15      Reserved for Factory   (*) open normal / closed factory
 J11      I/O Channel Ready      (*) open disabled  /  closed enabled
 J14 J13  Default Configuration at Power Up
          Cyls  Heads  SpT  MB     J14     J13     (J17)
 40MB (*)  981    5    17   40.7   open    open    open 
           524    4    40   40.9   open    closed  open
 80MB (*)  981   10    17   81.4   open    open    closed
           832    6    33   80.4   open    closed  closed
          1024    9    17   76.5   closed  open    closed
 (60MB)    762    4    39   58.0   closed  closed  closed       
 ------------------------------------------------------------------------
 (*) = Default      Note:  A spare jumper is supplied across J13 and J14.



>I have a 7131AT maxtor in my machine and setup info as follows:
>
>                1002 cylinders
>                8 heads
>                32 sectors
>                0 precomp
>                1002 LZ
>

********************* MICROPOLIS Micropolis micropolis ***********************


Drive		2105A		2112A
----------------------------------------
Unformatted MB	647		1220
Formatted MB	560		1050
Platters	5		8
Heads		8		15
Cylinders	1760		1760
----------------------------------------

Performance (both):

	Track to track (read)		1.5 msec
	Track to track (write)		2.5 msec
	Average				10 msec
	Max				25 msec
	Avg Rotational Latency		5.56 msec
	Rotational speed		5400 rpm (+/- 5%)
	Data Transfer Rate		upto 5Mbytes/sec
	Internal data rate		24-40 Mbits/sec

BIOS Settings:

2105A		1084 cyl	16 heads	63 sectors
2112A*	master	1024 cyl	16 heads	63 sectors
	slave	1010 cyl	16 heads	63 sectors
		
* the 2112A emulates both master and slave


Jumpers (labelled J6 on the drive)

	----
	|oo| W1\ only these 2 are used
	|oo| W2/
	|oo|
	|oo|
	|oo|
	----

	W2	W1
	--	--
	in	in	2112A only - drive emulates both master + slave
	in	out	Drive is master, slave is present
	out	in	Drive is slave
	out	out	Drive is master, no slave present (ie single drive)


*****************   MICROSCIENCE Microscience microscience   *****************

MicroScience 

Model: 7100-00
Heads: 7
Cylinders: 855
S/T: 35 (?)
Size: 105M


Model # 8040-00.
Size 40M  5hd/17sec/977cyl

Model	# cyls	# heads	spt	lz	precomp		cap (formatted)
7070-20	960	5	35	960	960		86 MB
7100-00	855	7	35	855	855		107 MB
7100-20	960	7	35	960	960		120 MB
8040	1024	2	40	1024	1024		41 MB

(NOTE: I have no jumper information on the model 8040)
On the 7xxx series the jumper pins are bent parallel to the board. When 
they are pointing toward you #1 is on the left, there are 8 altogether.

single drive		all open
master drive		1-2 shorted
slave drive		7-8 shorted


***************   MINISCRIBE Miniscribe miniscribe    ************************

Miniscribe

MODEL   AT               CAP   CYC  H  RWC  WPC ENC  RATE ACCESS  SPT COMMENTS 
8225AT            3.5"    21   745  2  -    -        8    28 MS    28
8051AT            3.5"    42   745  4  -    -        8    28 MS    28
8450AT            3.5"    42   745  4  -    -        8    40 MS    28

Master(2):  5-6
Slave(2):   1-2
Single:     1-3 (shunt storage)


***************************   NEC Nec nec   *********************************

NEC     D3735,  40 MB
BIOS:	Cyl 537     Head 4	sect 41

NEC	D3755,	105 MB
BIOS:	Cyl 625     Head 8	sect 41

NEC	D3756, 105 MB
BIOS:	Cyl 1005    Head 12	sect 17

NEC	D3741,	44 MB
BIOS:	Cyl 423	    Head 8	sect 26		WPcom 0		LZone 424
 

Jumper	JP12	JP13	    (for all above NEC drives)
Single  0       0
Master	1	0
Slave   1       1

There have been reported difficulties in using WD Caviar as Master and
NEC drives as slave - the other way it works.



************************  QUANTUM Quantum quantum   *************************

Logical Specs for Quantum AT Drives
COMPLIMENTS OF COMPUTER BROKERS OF CANADA


Model       Cap     Avg Acc	Cylinders     Heads    Sectors/Track
            (MB)     (ms)

40AT        42        19           965          5            17
80AT        84        19           965         10            17
120AT       120       15           814          9            32
170AT       168       15           968         10            34
210AT       209       15           873         13            36
425AT       426       14          1021         16            51
LPS  52AT   52        17           751          8            17
LPS  80AT   83        17           611         16            17
LPS 105AT   105       17           755         16            17
LPS 120AT   122       16           901          5            53
LPS 170AT   160       15	   968	       10	     34
LPS 240AT   245       16           723         13            51
LPS 540A    see below

=================================================
Legend:  1=Jumper Installed  0=No Jumper
=================================================

40 & 80 AT Jumpers

DS  SS   Meaning
1   0    Single drive configuration
1   1    Master of dual drive
0   0    Slave of dual drive
0   1    Self-Seek Test

=======================================================

120, 170, 210 & 425 AT Jumpers

DS  SP  SS   Meaning
0   0   0    Slave when the Master is Quantum PRODRIVE other than 40/80A
0   0   1    Slave in PRODRIVE 40/80A mode
0   1   0    Slave when Master is non Quantum Drive
0   1   1    Not Used
1   0   1    Master drive PDIAG mode checking DASP for slave
1   1   0    Master in PDIAG mode using SP to check if slave present
1   1   1    Master in 40/80A mode using SP to check if slave present
1   0   0    Single drive

=======================================================

LPS 52, 80, 105, 120, 170 & 240 AT Jumpers
DS  SP  DM*  Meaning
0   0   0    Slave in standard PDIAG mode for compatibility with drives that use
             PDIAG-line to handle Master/Slave communications
0   0   1    Slave in PRODRIVE 40/80A mode compat. without using PDIAG line
0   1   0    Self Test
0   1   1    Self Test
1   0   0    Master in PDIAG mode using DASP to check for Slave
1   0   1    Master in 40/80A Mode using DASP to check for Slave
1   1   0    Master in PDIAG mode using SP to check for Slave without
             checking DASP
1   1   1    Master in 40/80A mode using SP to check for Slave without
             checking DASP


======================================================================
* While my Spec form marked the jumper name DM, it is labeled as CS on
  my LPS 240AT drive.

Quantum LPS540A:
1120 cyl.    16 hds.     59 sec/trck    541MB
1024 cyl.    16 hds.     63 sec/trck    528MB

The second option is for those that will use the drive under DOS (1024 limit
without driver support).

9-12ms avg. access time
ECC Reed Solomon, 4,500 rpm, local bus support, fast multiword DMA, 128k cache
(of this 32k is used by firmware), read/write caching.


The QUANTUM ELS series:

Model       Cap     Avg Acc     Cylinders     Heads    Sectors/Track
            (MB)     (ms)
 
ELS42AT        42        -           968          5             17
ELS85AT        85        -           977          10            17
ELS127AT       127       -           919          16            17
ELS170AT       170       -           1011         15            22

Write precomp = 0 for all Quantum drives ( probably no significance)
Landing Zone = Cylinders

Straps: If an ELS drive is 
	master only, use DS
	master with slave, DS or, DS and SP in some cases
	slave, no strap


*********************	RODIME Rodime rodime   ******************************

Information for RO 3008A and RO 3009A series hard disk drives:

Drive Types

   Model	Cyls	Hds	Sectors/Trk	 No. blocks	Formatted Cap.
  -------	----	---	-----------	 ----------	--------------
  RO3058A	868	 3	    34		   88,536	 45.33 MByets
  RO3088A	868	 5	    34		  147,560	 75.55 MByets
  RO3095A	923	 5	    34		  156,910	 80.33 MByets
  RO3128A	868	 7	    34		  206,584	105.77 MByets
  RO3135A	923	 7	    34		  219,674	112.47 MByets
 
  RO3059A	217	15	    28		   91,158	 46.67 MByets
  RO3089A	325	15	    28		  136,737	 70.00 MByets
  RO3129A	492	15	    28		  206,645	105.80 MByets
  RO3139A	523	15	    28		  219,735	112.50 MByets
  RO3209A	759	15	    28		  319,053	163.35 MByets
  RO3259A	976	15	    28		  410,211	210.02 MByets


Link Options

   In order to install the Rodime Ro 3000A series drives the dumpers for 
the single/dual drive and LED operation on the drive need to be set as 
described in the relevant product specification.
   I a single drive environment the drive is described as a Master.
   In a dual drive environment the drives are described as a Master and a
Slave. This is due to the protocal the takes place between the two drives 
when performing diagnostics.
   There are four links, LK1, LK2, LK4 and LK5, adjacent to the 40 way 
interface connector. They have the following functions and are described 
in order as viewed from the end of the drive, with the first jumper 
described nearest the 40 way interface connector.

LK2: LED 
     When fitted, this jumper connects the LED drive to pin 39 of the
     interface. This allows a LED to be connected to the interface. An
     external current limiting resistor needs to be fitted in series with
     the LED when this option is selected. The value of the resistor will
     be dependant on the LED type chosen but will be in the range of 130
     Ohms ot 220 Ohms.

LK1: Dual Drives
     This jumper must be fitted when two drives are attached to a single
     bus. It fallows communication across the 40 way interface connector,
     indicating, to the Master drive, the presence of a Slave.

LK4: Master
     When fitted this signifies that the drive jumpered is a Master. If
     there are two drives connected on a single bus then only one may be
     jumpered in this way.

LK5: IOChRdy
     When fitted this connects the IOChRdy signal to the drive, it is 
     fitted when the drive is used in host systems that have a higher
     data transfer rate than the drive i.e. greater than 4 MBytes per
     second when using 1:1 interleave. This jumper is not normally 
     fitted as most hosts transfer at a lower rate than 4 MBytes per
     second.

   There are four possible Master/Slave configurations in which a drive(s)
may be jumpered:

     Master, single drive with LED on interface		LK2 & LK4 fitted.
     Master, single drive without LED on interface	LK4 only fitted.
     Master, dual drive without LED on interface	LK4 & LK1 fitted.
     Slave, dual drive without LED on interface		No jumpers fitted.
     Master, dual drive with LED on interface		LK4, LK1 & LK2 fitted.
     Slave, dual drive with LED on interface		LK2 only fitted.

   The Master drive will delay power-up for approximately two seconds to
reduce power surges in applications where dual drives are used.

   The other connections for a LED will be found close to the 28 way 
connector at the other end of the drive. This LED driver is not affected
by the link options. An internal current limiting resistor is on the 
drive for this LED driver. Refer to the product specification for further
details.


*************************** SAMSUNG Samsung samsung  *************************

            CYL   hd  Sectors
SHD-3101A   776    8    33        (100 MB)  (MB = 1024 bytes)
SHD-3061A   977    7    17        (56.76 MB)
SHD-3062A   917   15    17        (114 MB)

for drive SHD-3101A, SHD-3061A and SHD-3062A

                             2 drives
Jumper     1 drive      Master       Slave
C/D           J           J            NJ
DSP          NJ           J            NJ
ACT           J          (1)           (1)
HSP          NJ          NJ            (2)
                       J = Jumpered
                      NJ = No Jumpered

(1) In a two-drive system,it is possible to drive one LED
    with both drives. An external current limiting resister is required

(2) If the drive is connected to a host that requires that the - DIRVE SLAVE
    PRESENT be supplied from the slave drive via the interface signal -
    HOST SLV/ACT, then this jumper must be installed, the ACT jumper must
    not be installed because the two jumpers are mutually exclusive



***************************  SEAGATE Seagate seagate  *************************

There is a list of most Seagate HD (including MFM, SCSI, ESDIand IDE) on
every Simtel mirror under

/msdos/dskutl/1seagate.zip

It contains info about the following drives:

	    st1144a	st138a	    st274a	st3283a
st1057a     st1156a	st1400a     st280a	st351ax
st1090a     st1162a	st1401a     st3051a	st9051a
st1102a     st1186a	st1480a     st3096a	st9077a
st1111a     st1201a	st157a	    st3120a	st9096a
st1126a     st1239a	st2274a     st3144a	st9144a
st1133a     st125a	st2383a     st325ax

additional info:

ST3243A     204 MB	Cyl/Hd/spt  1024/12/34
ST351AX     41	MB		    820/6/17
ST9235A     200 MB		    985/13/32

and also...

pd1:<msdos.info>	(on SIMTEL mirrors)
1SGATHTX.ZIP    Seagate tech support's disk ref (needs HHV20)

This is a concise and complete source of information for all hard disks
that Seagate makes, including MFM, RLL, IDE, and SCSI types.  This
information includes:

        Detailed technical specifications for each drive
        Switch and Jumper settings for each drive (more than just settings
                for BIOSs and low--level formatting routines)
        Miscellaneous notes about each drive

This is the most up-to-date information that Seagate provides on its BBS.
It is dated 05/14/93.

This file is a hypertext version of file 1SEAGATE.ZIP and requires
HHV20.ZIP to view it.


*******************   TEAC Teac teac  ********************

Model: SD-3105

                Cyls.   Heads   Sect/T  PreCmp  LZone   Capacity
                ------  ------  ------  ------  ------  ---------
Physical         1282       4      40       -       -   105021440
BIOS (AMI)        641       8      40       0       0   105021440 (100.2M)
     (Award)      926      13      17       0       0   104778752  (99.9M)
     (Phoenix)    776       8      33       0       0   104890368 (100.0M)

Connectors and Jumpers:

   +----+                    1           Jumper  Function
   |....| +---+ +-------/ /---+   2 0       0    ON:  -ACT selected (ext.LED)
   |    | |...| |::::::/ /::::|  ::::            OFF: -SLV PRESENT selected
   +----+ +---+ +-----/ /-----+  3 1        1    ON:  Two HDD's
     J2     J7  40    J1         ----            OFF: Single HDD
   Power (Power)    Signal      Jumpers     2    ON:  Master (/Single)
                                                 OFF: Slave (with 2 units used)
                                            3    ON:  -I/O CH RDY not output
                                                 OFF: -I/O CH RDY is output
Master Slave Settings:

Jumper no.:   1     2
-----------------------
Single....:   0     1                            1, ON  = jumpered
Master....:   1     1                            0, OFF = not jumpered
Slave.....:   1     0


*********************	TOSHIBA Toshiba toshiba   ***************************

		    cap     Cyl     Hd	    spt
MK1122FC	    41	    977     2	    43
MK2024FC	    82	    977     4	    43
MK2124FC	    124     934     16	    17
MK2224FC	    203     684     16	    38
MK234FCH	    101     845     7	    35

Toshiba MK 234FCF.  
	845	Cyl
	7	Head
	0	Pre
	845	LZ
	35	Sectors
	101	Size
The jumpers settings I got from Toshiba.  They refer to 
connector PJ10, the 1st being the pair of pins closet to the
outside of the drive and the 6th being the pair closest to
center of the drive.  
	configuration		jumpers on
	------------		----------
	single drive		1st and 3rd
	master w/ slave		1st, 3rd, and 4th
	slave			1st


**************** WESTERN DIGITAL Western Digital western digital **************

Caviar series:

Name        Size (Mb)    Cylinders   Heads   Sectors
----------------------------------------------------
WDAC140      40.7         980            5        17
WDAC280      81.3         980           10        17
WDAC1170    163 	 1010		 6	  55
WDAC2120    119.0        1024           14        17
WDAC2170    162.7        1010            6        55
WDAC2200    202.8         989           12        35
WDAC2250    244 	 1010		 9	  55
WDAC2340    325.4        1010           12        55
WDAC2420    405.6         989           15        56


> My 1st HD was a Quantum (LPS) 105AT (I assume th LPS, as I haven't any 
> docs.) 
> >LPS 105AT   105       17           755         16            17
> The second was a Western Digital Caviar 340Mb:
> >WDAC2340    325.4        1010           12        55
> Using the information from your document, I set up the Quantum as master
> and the WDC as slave. This worked fine most of the time, but when booting
> sometimes HDD-controller errors occured. When I switched the drives (WDC
> as master, Quantum as slave) it worked perfectly, as has done ever since.

Manufacturer: Western Digital
Serie:        Caviar
Name:         WDAC2420
Size(Mb):     405.6
Cylinders:    989
Heads:        15
Sectors:      56
(uses dynamic translation)
Jumpers:      CP MA SL

The drive runs as a slave with a WDAC2200 as master just fine.


Please note that these are the *recommended* CMOS parameters. All the disks 
support so-called dynamic translation, and should thus be able to work with
any parameters having fewer sectors than the total number of sectors on
the disk.

Now, according to the manual, the jumper settings are as follows:

Jumper                               CP   MA   SL
-------------------------------------------------
Single                                0    0    0
Master                                0    1    0
Slave                                 0    0    1
Slave with Conner CP342 or CP3022     1    0    1   


Maybe there are 2 kinds of Caviar's floating around: 

If your jumpers read MA SL and SI then use:
Jumper	SI	MA	SL
Single	1	0	0
Master	0	1	0
Slave	0	0	1

There have been reported difficulties in using WD Caviar as Master and
NEC drives as slave - the other way it works.
> When I installed a Conner CP3204F (203 MB) as master and a WD Caviar 2200
> (203 MB) as slave, both with and without the "CP" jumper, the Caviar had
> seemingly normal behaviour. However, when doing writes to the Caviar, once
> in a while it would overwrite directories etc. Using FASTBACK was almost
> impossible.
> 
> The workaround is to install the Caviar as the master, and the Conner
> as the slave.


> I had a WD pirana 4200 (212 mb) IDE drive and added a Caviar 2340 (341 mb)
> drive.  No matter what I did with the CMOS settings, as soon as I define
> the D drive (as anything) and rebooted, it would hang for about 2 minutes
> and then report "D: drive failure".  I am using an intelligent IDE controller
> since my AMI bios was too old to support IDE drives.
> 
> The fix was to call the 4200 the slave and the 2340 the master.
> All has been working fine since then.


WD93044-A  (40 MB)
BIOS-Settings 
977 cyln, 5 heads, 17 sect, LZone: 977 

+-------+ +---+---+---+  1: drive is master
| cable | | 1 | 2 | 3 |  2: drive is slave
+-------+ +---+---+---+  3: second drive is a conner-drive

No jumper set: this is the only drive.

--

WD93048-A
40 MB
Cyl 782
Heads 4
s/track 27

Jumper not known; try settings for WD93044-A

--

WDAH260     60MB    Cyl/Hd/spt	    1024 7 17
WDAH280     82MB		    980 10 17

WDAP4200    202MB		    987 12 35



********************  Useful telephone numbers...  ********************

Conner:
  BBS: 408-456-4415
  Talk info: 1-800-426-6637
  FaxBack: 408-456-4903

The "Talk info" number above is now a Fax-on-demand system.  Very nice,
considering both the incoming call and outgoing fax are paid for by them!
You can also speak with a human for technical assistance at this number.

	(Conner Europe (in UK)  ;  +44 628 777277 (voice)
				   +44 628 592801 (fax))
Miniscribe:     
  303-651-6000

Maxtor:
  Info/tech support: 800-262-9867
  FAX-back: 303-678-2618
  BBS: 303-678-2222
  They list their 800 number as 1(800)2-MAXTOR.

Quantum:
  408-894-4000
  408-944-0410 (Support)
  408-894-3218 (FAX)
  408-894-3214 (BBS)

Seagate:
  Info/tech support: 408-438-8222
  FAX-back: 408-438-2620
  BBS: 408-438-8771

Western Digital:
  Info/tech support: 714-932-4900
  BBS:
  U.S. 1200/2400    714-753-1234
  U.S. 9600         714-753-1068
  France 1200/2400  ..-331-69-85-3914 (? French code is 33 not 331)
  Germany 1200/2400 ..-49-89-922006-60
  U.K.  1200/2400   ..-44-372-360387

The US Toll free number for Western Digital tech support is
800-832-4778


*******************   last but not least   *****************

If I could help you with my little collection and if you live in a
part of the world far away from me, how about a postcard for my pinboard?
I will surely answer!

Carsten Grammes			
Saarbruecker Str. 47
D-66292 Riegelsberg
Germany

S) 5.0 Video

Q) 5.1  Can I use two video cards in the same system?

[From: uwvax!astroatc!nicmad!madnix!zaphod (Ron Bean)]

   In the past, the only way to do this was to use one Hercules-type
monochrome card and one color card (CGA, EGA, or VGA), because the
color cards all used the same address space.  Most DOS software will
only use one at a time (you can switch between them with the 'mode'
command), but debuggers and CAD programs often support this type of
dual-display system. You may have to change a setting on your VGA card
to make it run in 8-bit mode in order for this to work.
 
   Windows can also be set up this way. Include the line
DualDisplay=TRUE (or ON) in your SYSTEM.INI file, in the 386enh
section. If you open a DOS shell window and type MODE MONO, the shell
will appear on the monochrome monitor.
 
   There are now other types of video cards that don't share the VGA
address space, but these combinations don't seem to be supported by
software. Some types that have been suggested include TIGA, 8514A,
Hercules InColor, and a few other "accelerated" cards. Many EISA video
cards have fully addressable video apertures, and come with the
appropriate drivers.
 
   A few cards contain more than one VGA chipset and come with special
drivers that make it behave like a single VGA card, but they may be
expensive and hard to find.
 
   If you just want to display the same image on several monitors,
there are (expensive) signal splitters that will do this (try vendors
that specialize in things like cables and switchboxes). Signal
splitters for EGA/CGA are somewhat cheaper.


Q) 5.2  *What kinds of monitors are available?

Q) 5.3  *Can I get an RGB monitor to work with my PC?

Q) 5.4  *How can I hook more than one monitor to my video card?

Q) 5.5  *Which video card is best for DOS/Windows/X11/OS2?

Q) 5.6  *What is the black horizontal line on my monitor?

S) 6.0 Systems

Q) 6.1  *What should I upgrade first?

Q) 6.2  Do I need a CPU fan / heat sink

[From: jruchak@mtmis1.mis.semi.harris.com (John Anthony Ruchak)]

This is highly debatable.  In general, if you buy from a good,
self-respecting company, any additional cooling requirements would
have been taken care of before your system was delivered to you.
 
I'm responsible for PC maintenance at my site, and I don't worry about
additional cooling in any of the pre-packaged systems we receive.  All
rebuilt and/or upgraded 486-33 (or higher) systems do, however,
receive additional cooling because older cases may not provide
adequate ventilation for today's technology.  Additional cooling on
the infamously-hot Pentium (586) is always added.

So, do YOU need a CPU fan in YOUR system?  Probably not for "ready to
run out of the box systems."  If you are _REALLY_ worried that your
system is suffering from too much heat, consult with a reputable
service center.  They will not only answer your questions, but they
can also install any additional cooling systems that may be needed.  A
good rule of thumb, though - "don't try to fix what isn't broken."
In other words, if your system is working, don't look for trouble.

Q) 6.3  What does the turbo switch do?

[From: cls@truffula.sj.ca.us (Cameron L. Spitzer)]

It slows your system down so you can play games that were written
with timing mechanisms based on CPU execution rate.  I know of three
implementations:
1.  A programmable divider delivers the clock signal at two different
    speeds.
2.  Extra wait states are inserted in all memory cycles.
3.  Dummy DMA cycles or extra referesh cycles are inserted.
The first is by far the most common.

Q) 6.4  How does the front panel LED display measure the system's speed?

It doesn't.  The only useful information going to these displays is if
you are in turbo mode.  They have jumpers or dials behind the display
which you can use to set them to show any two arbitrary numbers (for
turbo and non-turbo modes).

Q) 6.5  Should I turn my computer/monitor off?

Turning a device on/off causes thermal stress.  Leaving it on causes
wear and tear (even on non moving parts).  The only thing you
shouldn't do is quickly power cycle the computer.  If you turn it
on/off, leave it that way for at least a few seconds.  Other than
that, it's up to you.

Q) 6.6  Are there any manufacturers/distributers who read the net?

Yes, it is known that Zeos, Gateway 2000, Adaptec, HP and others all
read the net to some extent.  However, for best results, use the
support phone numbers.

S) 7.0 Diagnostics

Q) 7.1  What do the POST beeps mean?

This section contains information on the following:

	IBM
	AMI 
	Phoenix
	DTK/ERSO XT BIOS
	MR BIOS
	Mylex 386 System BIOS
	Quadtel AT Compatible BIOS

[From: Shaun Burnett (burnesa@cat.com)]
 
POST (Power-On Self Test) beeps signal something is wrong with your
system.  The meaning of these beeps is BIOS dependent.  Below are the
audio codes for IBM, AMI, and Phoenix BIOS's.

IBM
Beep(s)                 Errant device
No beep                 Power supply, system board
1 short beep            System OK
2 short beeps           POST Error displayed on monitor
Repeating short beeps   Power supply, system board
3 long beeps            3270 keyboard card
1 long, 1 short beeps   System board
1 long, 2 short beeps   Display adapter (MDA, CGA)
1 long, 3 short beeps   EGA
Continuous beep         Power supply, system board


AMI
Beep(s)                 Failure
1 short                 DRAM refresh
2 short                 Parity circuit
3 short                 Base 64K RAM
4 short                 System timer
5 short                 Processor
6 short                 Keyboard controller Gate A20 error
7 short                 Virtual mode exception error
8 short                 Display memory R/W test
9 short                 ROM BIOS checksum
1 long, 3 short         Non-fatal--Conventional/extended memory
1 long, 8 short         Non-fatal--Display/retrace test


PHOENIX
Beep    Fatal Failures* Beep code      Non-Fatal Failures* code
1-1-3   CMOS write/read  (or real-     4-2-1   Timer tick interrupt test
         time clock read/write)                 (or in progress)
1-1-4   ROM BIOS checksum              4-2-2   Shutdown test (or in progress)
1-2-1   Programmable interval timer    4-2-3   Gate A20 failure
1-2-2   DMA initialization             4-2-4   Unexpected interrupt in
                                                protected mode
1-2-3   DMA page register write/read   4-3-1   RAM test in progress or
                                                address failure > FFFFh
1-2-4   SRAM test and configuration    4-3-3   Interval timer Channel 2
                                                (or test)
1-3-1   RAM refresh verification       4-3-4   Time-of-day clock (or test)
1-3-3   1st 64kb RAM chip or data      4-4-1   Serial port (or test)
         line failure, multibit
1-3-4   First 64K RAM odd/even logic   4-4-2   Parallel port (or test)
1-4-1   Address line failure first     4-4-3   Math coprocessor (or test)
         64K RAM
1-4-2   Parity failure first       low 1-1-2   System-board select
         64K RAM
2-1-1   Bit 0 first 64K RAM        low 1-1-3   Extended CMOS RAM
2-1-2   Bit 1 first 64K RAM
2-1-3   Bit 2 first 64K RAM
2-1-4   Bit 3 first 64K RAM
2-2-1   Bit 4 first 64K RAM
2-2-2   Bit 5 first 64K RAM
2-2-3   Bit 6 first 64K RAM
2-2-4   Bit 7 first 64K RAM
2-3-1   Bit 8 first 64K RAM
2-3-2   Bit 9 first 64K RAM
2-3-3   Bit 10 first 64K RAM
2-3-4   Bit 11 first 64K RAM
2-4-1   Bit 12 first 64K RAM
2-4-2   Bit 13 first 64K RAM
2-4-3   Bit 14 first 64K RAM
2-4-4   Bit 15 first 64K RAM
3-1-1   Slave DMA register
3-1-2   Master DMA register
3-1-3   Master interrupt mask
         register failure
3-1-4   Slave interrupt mask
         register failure
3-2-4   Keyboard controller test
         failure
3-3-4   Screen initialization
3-4-1   Screen retrace
3-4-2   Search for video ROM in
         progress (not failure)
* Unless otherwise noted.


[From: Will Spencer (will@gnu.ai.mit.edu)]

DTK/ERSO XT BIOS
 
1 short					- Begin POST and End POST
1 long, 1 short				- Floppy Disk Drive or Controller 
					  Failure
Continuous short			- Parity Error in First 64K RAM
Continuous tone				- First 64K RAM failure
1 long					- Keyboard Failed or Locked, Interrupt
					  or other system board error
long short, long short, long short	- Video Initialization Failure, or
				  	  Invalid Video Switch Setting

MR BIOS
 
:POST Code 1A Beep Codes
low high, low high low high high	- Real Time Clock is Not Updating
 
:POST Code 03 Beep Codes
low high, low low low			- ROM BIOS Checksum Test
 
:POST Code 04 Beep Codes
low high, high low low			- Page Register Test (Ports 81-8F)
 
:POST Code 05 Beep Codes
low high, low high low			- 8042 Keyboard Controller Selftest
 
:POST Code 07 Beep Codes
low high, high high low			- Memory Refresh Circuit Test
 
:POST Code 08 Beep Codes
low high, low low high			- Master (16bit) DMA Controller
					  Failure
low high, high low high			- Slave (8 bit) DMA Controller
					  Failure
 
:Post Code 0A Beep Codes
low high, low low low low		- Memory Bank 0 Pattern Test Failure
low high, high low low low		- Memory Bank 0 Parity Circuitry
					  Failure
low high, low high low low		- Memory Bank 0 Parity Error
low high, high high low low		- Memory Bank 0 Data Bus Failure
low high, low low high low		- Memory Bank 0 Address Bus Failure
low high, high low high low		- Memory Bank 0 Block Access Read
					  Failure
low high, low high high low		- Memory Bank 0 Block Access
					  Read/Write Failure
 
:POST Code 0B Beep Codes
low high, high high high low		- Master 8259 (Port 21 ) Failure
low high, low low low high		- Slave 8259 (Port A1) Failure
 
:POST Code 0C Beep Codes
low high, high low low high		- Master 8259 (Port 20) Interrupt
					  Address Error
low high, low high low high		- Slave 8259 (Port A0) Interrupt
					  Address Error
low high, high high low low		- 8259 (Port 20/A0) Interrupt
					  Address Error
low high, low low high high		- Master 8259 (Port 20) Stuck
					  Intercept Error
low high, high low high high		- Slave 8259 (Port A0) Stuck
					  Intercept Error
low high, low high high high		- System Timer 8254 CH0/IRQ0
					  Interrupt Failure
 
:POST Code 0D Beep Codes
low high, high high high high		- 8254 Channel 0 Test and
					  Initialization
 
:POST Code 0E Beep Codes
low high, low low low low high		- 8254 Channel-2 (Speaker) Failure
low high, high low low low high		- 8254 OUT2 (Speaker Detect) Failure
 
:POST Code 0F Beep Codes
low high, low high low low high		- CMOS RAM Read/Write Test Failure
low high, high high low low high	- RTC Periodic Interrupt / IRQ8
					  Failure
 
:POST Code 10 Beep Codes
low high, low low high low high		- Video Initialization and
					  (Cold-Boot) Signon Message
 
:POST Code 12 Beep Codes
low high, high low high low high	- Keyboard Controller Failure
 
:POST Code 17 Beep Codes
low high, low low low high high		- A20 Test Failure Due to 8042
					  Timeout
low high, high low low high high	- A20 Gate Stuck in Disabled State
 
:POST Code 19 Beep Codes
low high, low high high low high	- Memory Parity Error
low high, high high high low high	- IO Channel Error


Mylex 386 System BIOS
 
long					- Begin POST Beep Code
2 long					- Video Card Bad or No Video Card
long, short, long			- Keyboard Controller Error
long, 2 short, long			- Keyboard Error
long, 3 short, long			- Programmable Interrupt Controller
					  (8259-1) Error
long, 4 short, long			- Programmable Interrupt Controller
					  (8259-1) Error
long, 5 short, long			- DMA Page Register Error
long, 6 short, long			- RAM Refresh Error
long, 7 short, long			- RAM Data Test Error
long, 8 short, long			- RAM Parity Error
long, 9 short, long			- DMA Controller 1 Error
long, 10 short, long			- CMOS RAM Failure
long, 11 short, long			- DMA Controller 2 Error
long, 12 short, long			- CMOS RAM Battery Failure
long, 13 short, long			- CMOS Checksum Failed
long, 14 short, long			- BIOS ROM Checksum Failed
several long beeps			- Multiple failures

Quadtel AT Compatible BIOS
 
3 short					- Any Failure


Q) 7.2  What do the POST codes mean?

This section contains information on the following:

	IBM
	Award Modular BIOS
	Mylex 386 System BIOS
	Quadtel AT Compatible BIOS
	MR BIOS
	Checkpoint Codes for AMI BIOS  (pre-4/9/90)
	AMI BIOS
	AMI Color BIOS (after 2/1/91)
	EuroBIOS

[From: zz96sr@sdacs.ucsd.edu (Steve Rusk)]

     All personal computer error codes for the Power On Self Test, General
Diagnostics, and Advanced Diagnostics consist of a device number followed by
two digits other than 00.  (The device number plus 00 indicates successful
completion of the test.)

     This list is a compilation from various sources, including USENET's
Info-IBMPC Digest, IBM Technical Reference Manuals, and IBM Hardware,
Maintenance and Service manuals.

01x	Undetermined problem errors.
02x	Power supply errors.
1xx	System board errors.
101	System board error - Interrupt failure.
102	System board error - Timer failure.
103	System board error - Timer interrupt failure.
104	System board error - Protected mode failure.
105	System board error - Last 8042 command not accepted.
106	System board error - Converting logic test.
107	System board error - Hot NMI test.
108	System board error - Timer bus test.
109	Direct memory access test error.
121	Unexpected hardware interrupts occurred.
131	Cassette wrap test failed.
152
161	System Options Error-(Run SETUP) [Battery failure].
162	System options not set correctly-(Run SETUP).
163	Time and date not set-(Run SETUP).
164	Memory size error-(Run SETUP).
199	User-indicated configuration not correct.
2xx	Memory (RAM) errors.
201	Memory test failed.
202	Memory address error.
203	Memory address error.
3xx	Keyboard errors.
301	Keyboard did not respond to software reset correctly, or a stuck
	key failure was detected.  If a stuck key was detected, the
	scan code for the key is displayed in hexadecimal.  For
	example, the error code 49 301 indicates that key 73, the
	PgUp key, has failed (49 hex = 73 decimal).
302	User-indicated error from the keyboard test, or AT keylock
	is locked.
303	Keyboard or system unit error.
304	Keyboard or system unit error; CMOS does not match system.
4xx	Monochrome monitor errors.
401	Monochrome memory test, horizontal sync frequency test, or
	video test failed.
408	User-indicated display attributes failure.
416	User-indicated character set failure.
424	User-indicated 80 X 25 mode failure.
432	Parallel port test failed (monochrome adapter).
5xx	Color monitor errors.
501	 Color memory test failed, horizontal sync frequency test, or
	video test failed.
508	User-indicated display attribute failure.
516	User-indicated character set failure.
524	User-indicated 80 X 25 mode failure.
532	User-indicated 40 X 25 mode failure.
540	User-indicated 320 X 200 graphics mode failure.
548	User-indicated 640 X 200 graphics mode failure.
6xx	Diskette drive errors.
601	Diskette power-on diagnostics test failed.
602	Diskette test failed; boot record is not valid.
606	Diskette verifysd function failed.
607	Write-protected diskette.
608	Bad command diskette status returned.
610	Diskette initialization failed.
611	Timeout - diskette status returned.
612	Bad NEC - diskette status returned.
613	Bad DMA - diskette status returned.
621	Bad seek - diskette status returned.
622	Bad CRC - diskette status returned.
623	Record not found - diskette status returned.
624	Bad address mark - diskette status returned.
625	Bad NEC seek - diskette status returned.
626	Diskette data compare error.
7xx	8087 or 80287 math coprocessor errors.
9xx	Parallel printer adapter errors.
901	Parallel printer adapter test failed.
10xx	Reserved for parallel printer adapter.
11xx	Asynchronous communications adapter errors.
1101	Asynchronous communications adapter test failed.
12xx	Alternate asynchronous communications adapter errors.
1201	Alternate asynchronous communications adapter test failed.
13xx	Game control adapter errors.
1301	Game control adapter test failed.
1302	Joystick test failed.
14xx	Printer errors.
1401	Printer test failed.
1404	Matrix printer failed.
15xx	Synchronous data link control (SDLC) communications adapter errors.
1510	8255 port B failure.
1511	8255 port A failure.
1512	8255 port C failure.
1513	8253 timer 1 did not reach terminal count.
1514	8253 timer 1 stuck on.
1515	8253 timer 0 did not reach terminal count.
1516	8253 timer 0 stuck on.
1517	8253 timer 2 did not reach terminal count.
1518	8253 timer 2 stuck on.
1519	8273 port B error.
1520	8273 port A error.
1521	8273 command/read timeout.
1522	Interrupt level 4 failure.
1523	Ring Indicate stuck on.
1524	Receive clock stuck on.
1525	Transmit clock stuck on.
1526	Test indicate stuck on.
1527	Ring indicate not on.
1528	Receive clock not on.
1529	Transmit clock not on.
1530	Test indicate not on.
1531	Data set ready not on.
1532	Carrier detect not on.
1533	Clear to send not on.
1534	Data set ready stuck on.
1536	Clear to send stuck on.
1537	Level 3 interrupt failure.
1538	Receive interrupt results error.
1539	Wrap data miscompare.
1540	DMA channel 1 error.
1541	DMA channel 1 error.
1542	Error in 8273 error checking or status reporting.
1547	Stray interrupt level 4.
1548	Stray interrupt level 3.
1549	Interrupt presentation sequence timeout.
16xx	Display emulation errors (327x, 5520, 525x).
17xx	Fixed disk errors.
1701	Fixed disk POST error.
1702	Fixed disk adapter error.
1703	Fixed disk drive error.
1704	Fixed disk adapter or drive error.
1780	Fixed disk 0 failure.
1781	Fixed disk 1 failure.
1782	Fixed disk controller failure.
1790	Fixed disk 0 error.
1791	Fixed disk 1 error.
18xx	I/O expansion unit errors.
1801	I/O expansion unit POST error.
1810	Enable/Disable failure.
1811	Extender card warp test failed (disabled).
1812	High order address lines failure (disabled).
1813	Wait state failure (disabled).
1814	Enable/Disable could not be set on.
1815	Wait state failure (disabled).
1816	Extender card warp test failed (enabled).
1817	High order address lines failure (enabled).
1818	Disable not functioning.
1819	Wait request switch not set correctly.
1820	Receiver card wrap test failure.
1821	Receiver high order address lines failure.
19xx	3270 PC attachment card errors.
20xx	Binary synchronous communications (BSC) adapter errors.
2010	8255 port A failure.
2011	8255 port B failure.
2012	8255 port C failure.
2013	8253 timer 1 did not reach terminal count.
2014	8253 timer 1 stuck on.
2016	8253 timer 2 did not reach terminal count, or timer 2 stuck on.
2017	8251 Data set ready failed to come on.
2018	8251 Clear to send not sensed.
2019	8251 Data set ready stuck on.
2020	8251 Clear to send stuck on.
2021	8251 hardware reset failed.
2022	8251 software reset failed.
2023	8251 software "error reset" failed.
2024	8251 transmit ready did not come on.
2025	8251 receive ready did not come on.
2026	8251 could not force "overrun" error status.
2027	Interrupt failure - no timer interrupt.
2028	Interrupt failure - transmit, replace card or planar.
2029	Interrupt failure - transmit, replace card.
2030	Interrupt failure - receive, replace card or planar.
2031	Interrupt failure - receive, replace card.
2033	Ring indicate stuck on.
2034	Receive clock stuck on.
2035	Transmit clock stuck on.
2036	Test indicate stuck on.
2037	Ring indicate stuck on.
2038	Receive clock not on.
2039	Transmit clock not on.
2040	Test indicate not on.
2041	Data set ready not on.
2042	Carrier detect not on.
2043	Clear to send not on.
2044	Data set ready stuck on.
2045	Carrier detect stuck on.
2046	Clear to send stuck on.
2047	Unexpected transmit interrupt.
2048	Unexpected receive interrupt.
2049	Transmit data did not equal receive data.
2050	8251 detected overrun error.
2051	Lost data set ready during data wrap.
2052	Receive timeout during data wrap.
21xx	Alternate binary synchronous communications adapter errors.
2110	8255 port A failure.
2111	8255 port B failure.
2112	8255 port C failure.
2113	8253 timer 1 did not reach terminal count.
2114	8253 timer 1 stuck on.
2115	8253 timer 2 did not reach terminal count, or timer   2 stuck on.
2116	8251 Data set ready failed to come on.
2117	8251 Clear to send not sensed.
2118	8251 Data set ready stuck on.
2119	8251 Clear to send stuck on.
2120	8251 hardware reset failed.
2121	8251 software reset failed.
2122	8251 software "error reset" failed.
2123	8251 transmit ready did not come on.
2124	8251 receive ready did not come on.
2125	8251 could not force "overrun" error status.
2126	Interrupt failure - no timer interrupt.
2128	Interrupt failure - transmit, replace card or planar.
2129	Interrupt failure - transmit, replace card.
2130	Interrupt failure - receive, replace card or planar.
2131	Interrupt failure - receive, replace card.
2133	Ring indicate stuck on.
2134	Receive clock stuck on.
2135	Transmit clock stuck on.
2136	Test indicate stuck on.
2137	Ring indicate stuck on.
2138	Receive clock not on.
2139	Transmit clock not on.
2140	Test indicate not on.
2141	Data set ready not on.
2142	Carrier detect not on.
2143	Clear to send not on.
2144	Data set ready stuck on.
2145	Carrier detect stuck on.
2146	Clear to send stuck on.
2147	Unexpected transmit interrupt.
2148	Unexpected receive interrupt.
2149	Transmit data did not equal receive data.
2150	8251 detected overrun error.
2151	Lost data set ready during data wrap.
2152	Receive timeout during data wrap.
22xx	Cluster adapter errors.
24xx	Enhanced graphics adapter errors.
29xx	Color matrix printer errors.
2901
2902
2904
33xx	Compact printer errors.


[From: Will Spencer (will@gnu.ai.mit.edu)]

Award Modular BIOS
 
01	- Processor Test 1: Processor Status Verification
02	- Determine Post Type
03	- Clear 8042 Keyboard Controller
04	- Reset 8042 Keyboard Controller
05	- Get Manufacturing Status
06	- Initialize Chips (DMA, 8259's)
07	- Processor Test 2: Read/Write/Verify Registers with 
	  Data Pattern FF and 00
08	- Initialize CMOS Timer
09	- EPROM Checksum
0A	- Initialize Video Controller Register 6845
0B	- Test Timer (8254) Channel 0
0C	- Test Timer (8254) Channel 1
0D	- Test Timer (8254) Channel 2
0E	- Test CMOS Shutdown Byte
0F	- Text Extended CMOS
10	- Test DMA Channel 0
11	- Test DMA Channel 1
12	- Test DMA Page Registers
13	- Test Keyboard Controller
14	- Test Memory Refresh
15	- Test 1st 64K of System Memory
16	- Setup Interrupt Vector Table
17	- Setup Video I/O Operations
18	- Test Video Memory
19	- Test 8259 Mask Bits - Channel 1
1A	- Test 8259 Mask Bits - Channel 2
1B	- Test CMOS Battery Level
1C	- Test CMOS Checksum
1D	- Set Configuration from CMOS
1E	- Size System Memory
1F	- Test Found System Memory
20	- Test Stuck 8259 Interrupt Bits
21	- Test Suck NMI Bits (Parity I/O Check)
22	- Test 9259 Working
23	- Test Protected Mode
24	- Size Extended Memory
25	- Test Found Extended Memory
26	- Test Protected Mode Exceptions
27	- Setup Cache Control or Shadow RAM
28	- Setup 8242
29	- Reserved
2A	- Initialize Keyboard
2B	- Initialize Floppy Drive and Controller
2C	- Detect and Initialize COM Ports
2D	- Detect and Initialize LPT Ports
2E	- Initialize Hard Drive and Controller
2F	- Detect and Initialize Math Coprocessors
30	- Reserver
31	- Detect and Initialize Option ROMs
3B	- Initialize Secondary Cache w/OPTi Chipset (486 only)
CA	- Micronics Cache Initialization
CC	- NMI Handler Shutdown
EE	- Unexpected Processor Exceptiom
FF	- INT 19 Boot Attempt


Mylex 386 System BIOS
 
01	- CPU Test
02	- DMA Page Register Test
03	- Keyboard Controller Test
04	- BIOS ROM Checksum
05	- Send Keyboard Command Test
06	- CMOS RAM Test
08	- RAM Refresh Test
09	- First 64K Memory Test
0A	- DMA Controller Test
0B	- Initialize DMA
0C	- Interrupt Test
0D	- Determine RAM Size
0E	- Initialize Video of EGA/VGA Checksum
10	- Search for Monochrome Card
11	- Search for Color Card
12	- Word Splitter and Byte Shifter Test
13	- Keyboard Test
14	- RAM Test
15	- Timer Test
16	- Initialize Output Port of Keyboard Controller
17	- Keyboard Interrupt Test


Quadtel AT Compatible BIOS
 
02	- Flag Test
04	- Register Test
06	- System Hardware Initialization
08	- Initialize Chip Set Registers
0A	- BIOS ROM Checksum
0C	- DMA Page Register Test
0E	- 8254 Timer Test
10	- 8254 Timer Initialization
12	- 8237 DMA Controller Test
14	- 8237 DMA Initialization
16	- Initialize 8259/Reset Coprocessor
18	- 8259 Interrupt Controller Test
1A	- Memory Refresh Test
1C	- Base 64KB Address Test
1E	- Base 64KB Memory Test
20	- Base 64KB Test (Upper 16 bits)
22	- 8742 Keyboard Self Test
24	- MC146818 CMOS Test
26	- Start First Protected Mode Test
28	- Memory Sizing Test
2A	- Autosize Memory Chips
2C	- Chip Interleave Enable Test
2E	- First Protected Mode Test Exit
30	- Unexpected Shutdown
32	- System Board Memory Size
34	- Relocate Shadow Ram if Configured
36	- Configure EMS System
38	- Configure Wait States
3A	- ReTest 64K Base RAM
3C	- CPU Speed Calculation
3E	- Get Switches From 8042
40	- Configure CPU Speed
42	- Initialize Interrupt Vectors
44	- Verify Video Configuration
46	- Initialize Video System
48	- Test Unexpected Interrupts
4A	- Start Second Protected Mode Test
4C	- Verify LDT Instruction
4E	- Verify TR Instruction
50	- Verify LSL Instruction
52	- Verify LAR Instruction
54	- Verify VERR Instruction
56	- Unexpected Exception
58	- Address Line 20 Test
5A	- Keyboard Ready Test
5C	- Determine AT or XT Keyboard
5E	- Start Third Protected Mode Test
60	- Base Memory Test
62	- Base Memory Address Test
64	- Shadow Memory Test
66	- Extended Memory Test
68	- Extended Address Test
6A	- Determine Memory Size
6C	- Display Error Messages
6E	- Copy BIOS to Shadow Memory
70	- 8254 Clock Test
72	- MC146818 Real Time Clock Test
74	- Keyboard Stuck Key Test
76	- Initialize Hardware Interrupt Vectors
78	- Math Coprocessor Test
7A	- Determine COM Ports Available
7C	- Determine LPT Ports Available
7E	- Initialize BIOS Data Area
80	- Determine Floppy/Fixed Controller
82	- Floppy Disk Test
84	- Fixed Disk Test
86	- External ROM Scan
88	- System Key Lock Test
8A	- Wait for F1 Key Pressed
8C	- Final System Initialization
8E	- Interrupt 19 Boot Loader
B0	- Unexpected Interrupt


MR BIOS

(The post codes for MR BIOS are located with the post beeps)


Checkpoint Codes for AMI BIOS 
Release date 4/9/90 and after
 
Code       Meaning
 
01      NMI disabled and 286 register test about to start.
02      286 register test passed.
03      ROM BIOS checksum (32K at F800:0) passed.
04      Keyboard controller test with and without mouse passed.
05      Chipset initialization over, DMA and Interrupt controller disabled.
06      Video disabled and system timer test begin.
07      CH-2 of 8254 initialization half way.
08      CH-2 of timer initialization over.
09      CH-1 of timer initialization over.
0A      CH-0 of timer initialization over.
0B      Refresh started.
0C      System timer started.
0D      Refresh link toggling passed.
10      Refresh on and about to start 64K base memory test.
11      Address line test passed.
12      64K base memory test passed.
15      Interrupt vectors initialized.
17      Monochrome mode set.
18      Color mode set.
19      About to look for optional video ROM at segment C000 and give control
        to the optional video ROM if present.
1A      Return from optional video ROM.
1B      Shadow RAM enable/disable completed.
1C      Display memory read/write test for main display type as set in the
        CMOS setup program over.
1D      Display memory read/write test for alternate display type complete
        if main display memory read/write test returns error.
1E      Global equipment byte set for proper display type.
1F      Video mode set call for mono/color begins.
20      Video mode set completed.
21      ROM type 27256 verified.
23      Power on message displayed.
30      Virtual mode memory test about to begin.
31      Virtual mode memory test started.
32      Processor executing in virtual mode.
33      Memory address line test in progress.
34      Memory address line test in progress.
35      Memory below 1MB calculated.
36      Memory above 1MB calculated.
37      Memory test about to start.
38      Memory below 1MB initialized.
39      Memory above 1MB initialized.
3A      Memory size display initiated. This will be updated when the BIOS
        goes through the memory test.
3B      About to start below 1MB memory test.
3C      Memory test below 1MB completed and about to start above 1MB test.
3D      Memory test above 1MB completed.
3E      About to go to real mode.
3F      Shutdown successful and processor in real mode.
40      CACHE memory on and about to disable A20 address line.
41      A20 address line disable successful.
42      486 internal cache turned on.
43      About to start DMA controller test.
50      DMA page register test complete.
51      DMA unit-1 base register test about to start.
52      DMA unit-1 base register test complete.
53      DMA unit-2 base register test complete.
54      About to check F/F latch for unit-1 and unit-2.
55      F/F latch for both units checked.
56      DMA unit 1 and 2 programming over and about to initialize 8259
        interrupt controller.
57      8259 initialization over.
70      About to start keyboard test.
71      Keyboard controller BAT test over.
72      Keyboard interface test over, mouse interface test started.
73      Global data initialization for keyboard/mouse over.
74      Display 'SETUP' prompt and about to start floppy setup.
75      Floppy setup over.
76      Hard disk setup about to start.
77      Hard disk setup over.
79      About to initialize timer data area.
7A      Timer data initialized and about to verify CMOS battery power.
7B      CMOS battery verification over.
7D      About to analyze POST results.
7E      CMOS memory size updated.
7F      Look for <DEL> key and get into CMOS setup if found.
80      About to give control to optional ROM in segment C800 to DE00.
81      Optional ROM control over.
82      Check for printer ports and put the addresses in global data area.
83      Check for RS232 ports and put the addresses in global data area.
84      Coprpcessor detection over.
85      About to display soft error messages.
86      About to give control to system ROM at segment E000.
00      System ROM control at E000 over now give control to Int 19h boot 
        loader.


Checkpoint Codes for AMI BIOS 
Release date prior to 4/9/90 

Code    Meaning
01      NMI disabled & 286 reg. test about to start
02      286 register test over
03      ROM checksum OK
04      8259 initialization OK
05      CMOS pending interrupt disabled
06      Video disabled & system timer counting OK
07      CH-2 of 8253 test OK
08      CH-2 delta count test OK
09      CH-1 delta count test OK
0A      CH-0 delta count test OK
0B      Parity status cleared
0C      Refresh & system timer OK
0D      Refresh link toggling OK
0E      Refresh period ON/OFF 50% OK
10      Confirmed refresh ON & about to start 64K memory
11      Address line test OK
12      64K base memory test OK
13      Interrupt vectors initialized
14      8042 keyboard controller test OK
15      CMOS read/write test OK
16      CMOS checksum/battery check OK
17      Monochrome mode set OK
18      Color mode set OK
19      About to look for optional video ROM
1A      Optional video ROM control OK
1B      Display memory read/write test OK
1C      Display memory read/write test for alternate display OK
1D      Video retrace check OK
1E      Global equipment byte set for video OK
1F      Mode set call for Mono/Color OK
20      Video test OK
21      Video display OK
22      Power on message display OK
30      Virtual mode memory test about to begin
31      Virtual mode memory test started
32      Processor in virtual mode
33      Memory address line test in progress
34      Memory address line test in progress
35      Memory below 1MB calculated
36      Memory size computation OK
37      Memory test in progress
38      Memory initialization over below 1MB
39      Memory initialization over above 1MB
3A      Display memory size
3B      About to start below 1MB memory test
3C      Memory test below 1MB OK
3D      Memory test above 1MB OK
3E      About to go to real mode (shutdown)
3F      Shutdown successful and and entered in real mode
40      About to disable gate A-20 address line
41      Gate A-20 line disabled successfully
42      About to start DMA controller test
4E      Address line test OK
4F      Processor in real mode after shutdown
50      DMA page register test OK
51      DMA unit-1 base register test about to start
52      DMA unit-1 channel OK, about to begin CH-2
53      DMA CH-2 base register test OK
54      About to test f/f latch for unit-1
55      f/f latch test both unit OK
56      DMA unit 1 & 2 programmed OK
57      8259 initialization over
58      8259 mask register check OK
59      Master 8259 mask register OK, about to start slave
5A      About to check timer and keyboard interrupt level
5B      Timer interrupt OK
5C      About to test keyboard interrupt
5D      ERROR! timer/keyboard interrupt not in proper level
5E      8259 interrupt controller error
5F      8259 interrupt controller test OK
70      Start of keyboard test
71      Keyboard BAT test OK
72      Keyboard test OK
73      Keyboard global data initialization OK
74      Floppy setup about to start
75      Floppy setup OK
76      Hard disk setup about to start
77      Hard disk setup OK
79      About to initialize timer data area
7A      Verify CMOS battery power
7B      CMOS battery verification done
7D      About to analyze diagnostic test results for memory
7E      CMOS memory size update OK
7F      About to check optional ROM C000:0
80      Keyboard sensed to enable setup
81      Optional ROM control OK
82      Printer global data initialization OK
83      RS-232 global data initialization OK
84      80287 check/test OK
85      About to display soft error message
86      About to give control to system ROM E000:0
87      System ROM E000:0 check over
00      Control given to Int-19, boot loader


AMI BIOS
 
01	- 286 Register Test Failed
02	- ROM BIOS Checksum (32KB at F800:0) Failed
03	- ROM BIOS Checksum (32KB at F800:0) Passed
04	- 8259 Interrupt Controller Initialization
05	- Chipset Initialization Over, DMA & Interrupt Controller Disabled
06	- Video Disabled and System Timer Test Begin
07	- CH-2 of 8254 Initialization Half Way
08	- 8254 CH-2 Timer Test to be Completed
09	- 8254 CH-1 Timer Test to be Completed
0A	- 8254 CH-0 Timer Test to be Completed
0B	- DRAM Refresh Failure
0C	- System Timer Started
0D	- Refresh Link Toggling Passed
0E	- Refresh Period ON/OFF 50% OK
10	- Refresh ON and About to Start 64KB Base Memory Test
11	- Address Line Test Passed
12	- 64KB Base Memory Test Passed
13	- Interrupt Vectors Initialized
14	- 8042 Keyboard Controller Test Passed
15	- CMOS Read/Write Test Passed
16	- CNOS Checksum and Battery Check Passed
17	- Monochrome Mode Set
18	- Color Mode Set
19	- Give Control to the Optional Video ROM at Segment C0 if present
1A	- Return from Optional Video ROM
1B	- Display Memory Read/Write Test Passed
1C	- Alternate Display Memory Read/Write Test Passed
1D	- Video Retrace Check Passed
1E	- Global Equipment Byte Set for Proper Display Type
1F	- Video Mode Set Call for Mono/Color Begins
20	- Video Mode Set Completed
21	- ROM Type Verified, Video Display OK
22	- Power On Message Displayed
23	- Power On Message Displayed
30	- Virtual Mode Memory Test About to Begin
31	- Virtual Mode Memory Test Started
32	- Processor Executing in Virtual Mode
33	- Memory Address Line Test in Progress
34	- Memory Address Line Test in Progress
35	- Memory Below 1MB Calculated
36	- Memory Above 1MB Calculated, Memory Size Computation OK
37	- Memory Test About to Start
38	- Memory Below 1MB Initialized
39	- Memory Above 1MB Initialized
3A	- Memory Size Display Initiated
3B	- About to Start Below 1MB Memory Test
3C	- Memory Test Below 1MB Completed
3D	- Memory Test Above 1MB Completed
3E	- About to go to Real Mode (Shutdown)
3F	- Shutdown Successful and Processor in Real Mode
40	- Cache Memory ON and About to Disable A20 Address Line
41	- Gate A-20 Line Disabed Successfully
42	- 486 Internal Cache Turned ON
43	- About to Start DMA Controller Test
4E	- Address Line Test Passed
4F	- Processor in Real Mode After Shutdown
50	- DMA Page Register Test Complete
51	- DMA Unit-1 Base Register Test About to Start
52	- DMA Unit-1 Base Register Test Complete
53	- DMA Unit-2 Base Register Test Complete
54	- About to Check F/F Latch for Unit-1 and Unit-2
55	- F/F Latch for Both Units Checked
56	- DMA Unit-1 and 2 Programming Over
57	- 8259 Initialization Over
58	- 8259 Mask Register Check Passed
59	- Master 8259 Mask Register Passed
5A	- About to Check Timer and Keyboard Interrupt Level
5B	- Timer Interrupt Passed
5C	- About to Test Keyboard Interrupt
5D	- Error!  Timer/Keyboard Interrupt Not in Proper Level
5E	- 8259 Interrupt Controller Error
5F	- 8259 Interrupt Controller Test Passed
70	- About to Start Keyboard Test
71	- Keyboard Controller BAT Test Over
72	- Keyboard Interface Test Over, Mouse Interface Test Started
73	- Global Data Initialization for Keyboard/Mouse Over
74	- Display "Setup" Prompt and About to Start Floppy Setup
75	- Floppy Setup Over
76	- Hard Disk Setup About to Start
77	- Hard Disk Setup Over
79	- About to Initialize Timer Data Area
7A	- Time Data Area Initialized and About to Verify CMOS Battery Power
7B	- CMOS Battery Verification Over
7D	- About to Analyze POST Test Results
7E	- CMOS Memory Size Updated
7F	- Look for <DEL> Key and Get into CMOS Setup if Found
80	- About to Give Control to Optional ROM in Segment C800 to DE00 (Setup)
81	- Optional ROM Control Over
82	- Check for Printer Ports and put the Addresses in Global Data Area
83	- Check for RS232 Ports and Put the Addresses in Global Data Area
84	- Co-processor Detection Over
85	- About to Display Soft Error Messages
86	- About to Give Control to System ROM at Segment E000
87	- System ROM E000:0 Check Over


AMI Color BIOS after 2/1/91
	
00	- Going to Give Control to INT 19H Boot Loader
01	- Processor Register Test About to Start, and NMI to be Disabled
02	- Power On Delay Starting
03	- Any Initialization Before Keyboard BAT is in Progress
04	- Reading Keyboard SYS Bit, to Check Soft Reset/Power On
05	- Going to Enable ROM. i.e. Disable Shadow RAM/Cache if Any
06	- Calculating ROM BIOS Checksum
07	- Going to Issue the BAT Command to Keyboard Controller
08	- Going to Verify the BAT Command
09	- Keyboard Command Byte to be Written Next
0A	- Going to Write Command Byte Data
0B	- Going to Issue Pin-23,24 Blocking/Unblocking Command
0C	- NOP Command of Keyboard Controller to be Issued Next
0D	- CMOS Shutdown Register Test to be Done Next
0E	- Going to Calculate CMOS Checksum, and Update DIAG Byte
0F	- CMOS Initialization to begin (If "INIT CMOS IN EVERY BOOT IS SET")
10	- CMOS Status Register About to Init for Date and Time
11	- Going to Disable DMA and Interrupt Controllers
12	- About to Disable Video Display and Init Port-B
13	- Chipset Init/Auto Memory Detection About to begin
14	- 8254 Timer Test About to Start
15	- 8254 CH-2 Timer Test to be Completed
16	- 8254 CH-1 Timer Test to be Completed
17	- 8254 CH-0 Timer Test to be Completed
18	- About to Start Memory Refresh
19	- Memory Refresh Test to be Done Next
1A	- Going to Check 15 Micro Second On/Off Time
1B	- Base 64K Memory Test About to Start
20	- Address Line Test to be Done Next
21	- Going to do toggle Parity
22	- Going for Sequential Data R/W Test
23	- Any Setup Before Interrupt Vector Init About to Start
24	- Interrupt Vector Initialization About to begin
25	- Going to Read I/O Port of 8042 for Turbo Switch (if any)
26	- Going to Initialize Global Data for Turbo Switch
27	- Any Initialization After Interrupt Vector to be Done Next
28	- Going for Monochrome Mode Setting
29	- Going for Color Mode Setting
2A	- About to go for toggle Parity Before Optional ROM Check
2B	- About to do any Setup Required Before Optional Video ROM Check
2C	- About to Look for Optional Video ROM and Give Control
2D	- About to do any Processing after Video ROM Returns Control
2E	- If EGA/VGA Not Found, Then do Display Memory R/W Test
2F	- Display Memory R/W Test About to begin
30	- About to Look for the Retrace Checking
31	- About to do Alternate Display Memory R/W Test
32	- About to Look for the Alternate Display Retrace Checking
33	- Verification of Display Type with Switch Setting 
	  and Actual Card to begin
34	- Display Mode to be Set Next
35	- BIOS ROM Data Area About to be Checked
36	- Going to Set Cursor for Power On Message
37	- Going to Display the Power On Message
38	- Going to Read New Cursor Position
39	- Going to Display the Reference String
3A	- Going to Display the Hit <ESC> Message
3B	- Virtual Mode Memory Test About to Start
40	- Going to Verify from Video Memory
41	- Going to Prepare the Descriptor Tables
42	- Going to Enter in Virtual Mode for Memory Test
43	- Going to Enable Interrupts for Diagnostics Mode
44	- Going to Initialize Data to Check Memory Remap at 0:0
45	- Check for Memory Remap at 0:0 and Find the total System Memory Size
46	- About to go For Writing Patterns to Test Memory
47	- Going to Write Patterns in Base 640K Memory
48	- Going to Find Out Amount of Memory Below 1M Memory
49	- Going to Find Out Amount of Memory Above 1M Memory
4A	- Going for BIOS ROM Data Area Check
4B	- Going to Check <ESC> and to Clear Memory Below 1M for Soft Reset
4C	- Going to Clear Memory Above 1M
4D	- Going to Save the Memory Size
4E	- About to Display the First 64K Memory Test
4F	- Going for Sequential and Random Memory Test
50	- Going to Adjust Memory Size for Relocation/Shadow
51	- Memory Test Above 1M to Follow
52	- Going to Prepare to go Back to Real Mode
53	- Going to Enter in Real Mode
54	- Going to Restore Registers Saved During Preparation for Shutdown
55	- Going to Disable Gate A20 Address Line
56	- BIOS ROM Data Area About to be Checked
57	- BIOS ROM Data Area Check to be Completed
58	- Going to Clear Hit <ESC> Message
59	- About to Start DMA and Interrupt Controller Test
60	- About to Verify from Display Memory
61	- About to go For DMA #1 Base Register Test
62	- About to go For DMA #2 Base Register Test
63	- About to go For BIOS ROM Data Area Check
64	- BIOS ROM Data Area Check to be Completed
65	- About to Program DMA Unit 1 and 2
66	- 8259 Interrpt Controller Initialization
67	- About to Start Keyboard Test
80	- About to Issue Keyboard Reset Command
81	- About to Issue Keyboard Controller Interface Test Command
82	- About to Write Command Byte and Init Circular Buffer
83	- About to Check for Lock Key
84	- About to Check for Memory Size Mismatch with CMOS
85	- About to Display Soft Error and Check for Password or Bypass Setup
86	- About to do Programming Before Setup
87	- Going to CMOS Setup Program
88      - About to do Programming After Setup
89      - Going to Display Power On Screen Message
8A      - About to Display <WAIT...> Message, Mouse Check 
	  and Initialization Next
8B      - About to do Main and Video BIOS Shadow
8C      - Setup Options Programming After CMOS Setup About to Start
8D      - Going for Hard Disk, Floppy Reset
8E      - About to go For Floppy Check
8F      - Floppy Setup to Follow
90      - Test for Hard Disk Presence to be Done
91      - Hard Disk Setup to Follow
92	- About to go for BIOS ROM Data Area Check
93	- BIOS ROM Data Area Check to be Completed
94      - Going to Set Base and Extended Memory Size
95      - Going to Verify From Display Memory
96      - Going to do Any Init Before C800 Optional ROM Control
97      - Optional ROM Check and Control Will Be Done Next
98      - Give Control to Required Processing 
	  After Optional ROM Returns Control
99      - Going to Setup Timer Data Area and Printer Base Address
9A      - Going to Set the RS-232 Base Address
9B      - Going to do Any Initialization Before Co-Processor Test
9C      - Going to Initialize the Coprocessor Next
9D      - Going to do Any Initialization After Co-Processor Test
9E      - Going to Check Extd Keyboard, Keyboard ID and Num-Lock
9F      - Keyboard ID Command to be Issued
A0      - Keyboard ID Flag to be Reset
A1      - Cache Memory Test to Follow
A2      - Going to Display Any Soft Errors
A3      - Going to Set the Keyboard Typematic Rate
A4      - Going to Program Memory Wait States
A5      - Screen to be Cleared Next
A6      - Going to Enable Parity and NMI
A7      - Do Initialization Required Before Giving Control 
          to Optional ROM at E000
A8      - E000 ROM to Get Control Next
A9      - Going to do Any Initialization Required 
          After E000 Optional ROM Control
AA      - Going to Display the System Configuration


Post Codes for EuroBIOS v4.71
 
03	DMA Page registers OK
04	DMA Page registers failed
05	Keyboard did reply
06	Keyboard did not reply
07	Keyboard self-test passed
08	Keyboard self-test failed
09	8042 was able to read links
0A	8042 was unable to read links
0B	RATMON/DIAG link OK
0C	Keyboard accepted 60h command
0D	Keyboard did not accept 60h
0E	Keyboard parameter accepted
0F	Keyboard parameter not accepted
10	Able to read keyboard command byte
11	Unable to read keyboard command byte
12	Keyboard command byte came back OK
13	Keyboard command byte came back corrupt
14	RAM refresh clock ticking correctly
15	RAM refresh clock not ticking correctly
16	RAM bit test passed
17	RAM bit test failed
18	RAM parity OK
19	RAM parity error
1A	CMOS RAM passed
1B	CMOS RAM failed
1C	CMOS RAM battery OK
1D	CMOS RAM battery faulty
1E	CMOS RAM checksum passed
1F	CMOS RAM checksum failed
20	CMOS RAM battery fault bit set
21	DMA controllers passed
22	DMA controller 1 failed
23	DMA controller 2 failed
24	Protected mode entered safely
25	RAM test completed
26	ROM checksum correct
27	ROM checksum incorrect
28	Protected mode exit successful
29	Keyboard power-up reply received
2A	Keyboard power-up reply not received
2B	Keyboard disable command accepted
2C	Keyboard disable command not accepted
2D	No video display
2E	Reported errors
2F	About to halt
30	Protected mode entered safely
31	RAM test complete
32	PIC 1 (master) passed
33	PIC 1 (master) failed
34	PIC 2 (slave) passed
35	PIC 2 (slave) failed
36	Chipset initialised OK
37	Chipset initilize failed
38	Shadowed BIOS OK
39	Shadowed BIOS failed
3A	Shadowed video BIOS OK
3B	Shadowed video BIOS failed


Q) 7.3  *I think my cache is bad. What's a good diagnostic?

===============
Ralph Valentino   (ralf@chpc.org)  (ralf@wpi.wpi.edu)
Hardware Engineer,  Worcester  Polytechnic  Institute
Center for High Performance Computing, Marlborough MA

From ankh.iia.org!babbage.ece.uc.edu!news.kei.com!MathWorks.Com!noc.near.net!chpc.chpc.org!chpc.chpc.org!not-for-mail Sun Aug 14 17:59:27 1994
Path: ankh.iia.org!babbage.ece.uc.edu!news.kei.com!MathWorks.Com!noc.near.net!chpc.chpc.org!chpc.chpc.org!not-for-mail
From: ralf@chpc.org (Ralph Valentino)
Newsgroups: comp.sys.ibm.pc.hardware.video,comp.sys.ibm.pc.hardware.comm,comp.sys.ibm.pc.hardware.storage,comp.sys.ibm.pc.hardware.cd-rom,comp.sys.ibm.pc.hardware.systems,comp.sys.ibm.pc.hardware.networking,comp.sys.ibm.pc.hardware.chips,comp.sys.ibm.pc.hardware.misc,comp.answers,news.answers
Subject: comp.sys.ibm.pc.hardware.* Frequently Asked Questions (FAQ) Part 4/5
Followup-To: comp.sys.ibm.pc.hardware.misc
Date: 12 Aug 1994 02:08:02 -0400
Organization: Center For High Performance Computing
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Sender: ralf@chpc.chpc.org
Approved: news-answers-request@MIT.EDU
Distribution: world
Expires: 11 Sep 1994 00:00:00 GMT
Message-ID: <32f3k2$8fi@chpc.chpc.org>
Reply-To: ralf@wpi.edu
NNTP-Posting-Host: localhost.chpc.org
Summary: This is a monthly posting containing a list of Frequently
	 Asked Questions (and their answers) pertaining to hardware
	 and IBM PC clones.  It should be read by anyone who wishes
	 to post to any group in the comp.sys.ibm.pc.hardware.*
	 hierarchy.
Xref: ankh.iia.org comp.sys.ibm.pc.hardware.video:9602 comp.sys.ibm.pc.hardware.comm:3135 comp.sys.ibm.pc.hardware.storage:7353 comp.sys.ibm.pc.hardware.cd-rom:4235 comp.sys.ibm.pc.hardware.systems:4216 comp.sys.ibm.pc.hardware.networking:2185 comp.sys.ibm.pc.hardware.chips:7714 comp.sys.ibm.pc.hardware.misc:7818 comp.answers:3111 news.answers:9228

Archive-name: pc-hardware-faq/part4
Last-modified: 1994/08/10
Version: 1.7


S) 8.0 Misc

Q) 8.1  What is the pin out for ...?

[From: ralf@wpi.wpi.edu (Ralph Valentino)]

This is a list of the pinouts to the more common PC hardware
interfaces.  It is by no means complete.  While I have taken care not
to make any mistakes, I urge you to take caution when using these
tables.  Also, please keep in mind that these are only tables, they
are not a guide to hardware hacking and do not attempt to explain
drive capabilities, signal timings, handling care, or other interface
issues.  As always, make sure you know what you're doing before you
start hooking wires to your PC.

 5pin DIN Male          DB15-S Male
    --+--               ----------------------
   /  ^  \              \   1  2  3  4  5    /
  | 1   3 |              \ 6  7  8  9 10    /
   \ 425 /                \ 11 12 13 14 15 /
    -----                  ----------------

DB9 (DE-9) Male                DB15 (DA-15) Male
-------------           --------------------------
\ 1 2 3 4 5 /           \ 1  2  3  4  5  6  7  8 /
 \ 6 7 8 9 /             \ 9  10 11 12 13 14 15 /
  ---------               ----------------------

DB25 Male                             IDC-50 Male
 ------------------------------        -------------------
 \ 1  2  3  4  5  7  8 ... 13 /       | 1  3  5  7 ... 49 |
  \ 14 15 16 17 18 .......25 /        | 2  4  6  8 ... 50 |
   --------------------------          -------------------

(Power Connector) Male
  __________
 /          \
| 4  3  2  1 |
 ------------

30 pin SIMM                         72 pin SIMM
-------------------------------     ---------------------------------------
|                             |     |                                     |
 )                            |      )                 _                  |
 --|||||||||||||||||||||||||---      --|||||||||||||||/ \|||||||||||||||---
   1                       30          1             36  37            72

EISA/ISA/VLB
-----------------------------------------------
|            (component side)                 |
|                                             |
|   VLB   __ ISA-16bit __       ISA-8bit    __|
 |||||||||  |||||||||||  ||||||||||||||||||| A1(front)/B1(back)
             | | | | |    | | | | | | | | |   <-EISA
                   C1/D1                    E1(front)/F1(back)
                  G1/H1


        PCI Cards Universal/3.3V/5V and 32/64 bit.

PCI Universal Card 32/64 bit
 ----------------------------------------------------------------
|    PCI         Component Side (side B)                         |
|                                                                |
|                                                                |
|                                                optional        |
|    ____     mandatory 32-bit pins            64-bit pins  _____|
|___|    |||||||--|||||||||||||||||--|||||||--||||||||||||||
         ^     ^  ^               ^  ^     ^  ^            ^
       b01   b11  b14           b49  b52 b62  b63          b94

PCI 5V Card 32/64 bit
|                                                optional        |
|    ____     mandatory 32-bit pins            64-bit pins  _____|
|___|    ||||||||||||||||||||||||||--|||||||--||||||||||||||

PCI 3.3V Card 32/64 bit
|                                                optional        |
|    ____     mandatory 32-bit pins            64-bit pins  _____|
|___|    |||||||--||||||||||||||||||||||||||--||||||||||||||


Power Connector Male      Speaker Connector        Turbo Indicator Connector
pin     assignment        pin     assignment       pin     assignment
1       +12V              1       -Speaker         1       +5V
2       +12V return       2       [key]            2       -High Speed
3       +5V return        3       GND              3       +5V
4       +5V               4       +Speaker +5V


AT LED Power and Key Lock     AT Backup Battery  
pin     assignment	      pin     assignment 
1       LED power	      1       Batt+      
2       GND		      2       [key]      
3       GND		      3       GND        
4       Key Switch	      4       GND        
5       GND


Motherboard Power Connectors
pin     P8 assignment          pin     P9 assignment 
1       Power Good             1       GND
2       +5v  (or N.C.)         2       GND
3       +12v                   3       -5v
4       -12v                   4       +5v
5       GND                    5       +5v
6       GND                    6       +5v


MIDI 5pin DIN
   MIDI In                 MIDI Out
pin     assignment      pin     assignment
1       N/C             1       N/C
2       N/C             2       GND
3       N/C             3       N/C
4       Current Src     4       Current Sync
5       Current Sync    5       Current Src


Floppy Disk Controller IDC-34 Male
pin     assignment      pin     assignment
1       GND             2       Density Select
3       GND             4       (reserved)
5       GND             6       (reserved)
7       GND             8       Index
9       GND             10      Motor Enable A
11      GND             12      Drive Sel B
13      GND             14      Drive Sel A
15      GND             16      Motor Enable B
17      GND             18      Direction
19      GND             20      Step
21      GND             22      Write Data
23      GND             24      Floppy Write Enable
25      GND             26      Track 0
27      GND             28      Write Protect
29      GND             30      Read Data
31      GND             32      Head Select
33      GND             34      Disk Change


Game Port DB15-Female
pin     assignment      pin     assignment
1       +5V DC          2       Button 4 (A_PB1)
3       Position 0(A_X) 4       GND
5       GND             6       Position 1 (A_Y)
7       Button 5(A_PB2) 8       +5V DC
9       +5V DC          10      Button 6 (B_PB1)
11      Position 2(B_X) 12      GND
13      Position 3(B_Y) 14      Button 7 (B_PB2)
15      +5V DC


Serial Port DB9-Male DB25-Male
9-pin   25-pin  assignment
1       8       DCD (Data Carrier Detect)
2       3       RX  (Receive Data)
3       2       TX  (Transmit Data)
4       20      DTR (Data Terminal Ready)
5       7       GND (Signal Ground)
6       6       DSR (Data Set Ready)
7       4       RTS (Request To Send)
8       5       CTS (Clear To Send)
9       22      RI  (Ring Indicator)

Parallel Port DB25-Female
pin     assignment      pin     assignment
1       -Strobe         2       Data 0
3       Data 1          4       Data 2
5       Data 3          6       Data 4
7       Data 5          8       Data 6
9       Data 7          10      -Ack
11      Busy            12      Paper Empty
13      Select          14      -Auto Feed
15      -Error          16      -Init
17      -Slct in        18      GND
19      GND             20      GND
21      GND             22      GND
23      GND             24      GND
25      GND


Parallel Port Centronics-36
1       -Strobe         2       Data 0
3       Data 1          4       Data 2
5       Data 3          6       Data 4
7       Data 5          8       Data 6
9       Data 7          10      -Ack
11      Busy            12      Paper Empty
13      Select          14      -Auto Feed
15      {OSCXT}         16      Signal GND
17      Frame GND       18      +5v
19      GND             20      GND
21      GND             22      GND
23      GND             24      GND
25      GND             26      GND
27      GND             28      GND
29      GND             30      GND
31      -Prime          32      -Error
33      Signal GND      34      N/C
35      N/C             36      N/C


AT Keyboard Connector 5pin-DIN		Xt Keyboard Connector 5pin-DIN
pin     assignment                      pin     assignment
1       CLK/CTS (open-collector)        1       CLK/CTS (open-collector)
2       RxD/TxD/RTS (open-collector)    2       Keyboard Data
3       N/C                             3       Reset
4       GND                             4       GND
5       +5V                             5       +5V


IDE Hard Disk Interface IDC-40 Male
pin     assignment      pin     assignment
1       -Reset          2       GND
3       Data 7          4       Data 8
5       Data 6          6       Data 9
7       Data 5          8       Data 10
9       Data 4          10      Data 11
11      Data 3          12      Data 12
13      Data 2          14      Data 13
15      Data 1          16      Data 14
17      Data 0          18      Data 15
19      GND             20      Key
21      (reserved)      22      GND
23      -IOW            24      GND
25      -IOR            26      GND
27      IO Chrdy        28      Ale
29      (reserved)      30      GND
31      IRQ14           32      -IOCS16
33      Addr 1          34      (reserved)
35      Addr 0          36      Addr 2
37      -CS0 (1F0-1F7)  38      -CS1 (3f6-3f7)
39      -Active         40      GND


ESDI Hard Disk Interface IDC-34 Male, IDC-20 Male
               ESDI IDC-34
pin     assignment      pin     assignment
1       GND             2       Head Sel 3
3       GND             4       Head Sel 2
5       GND             6       Write Gate
7       GND             8       Config/Stat Data
9       GND             10      Transfer Ack
11      GND             12      Attn
13      GND             14      Head Sel 0
15      GND             16      Sect/Add MK Found
17      GND             18      Head Sel 1
19      GND             20      Index
21      GND             22      Ready
23      GND             24      Trans Req
25      GND             26      Drive Sel 1
27      GND             28      Drive Sel 2
29      GND             30      Drive Sel 3
31      GND             32      Read Gate
33      GND             34      Command Data

               ESDI IDC-20
pin     assignment      pin     assignment
1       Drive Selected  2       Sect/Add MK Found
3       Seek Complete   4       Addr Mark Enable
5       (reserved)      6       GND
7       Write Clk+      8       Write Clk-
9       Cartridge Chng  10      Read Ref Clk+
11      Read Ref Clk-   12      GND
13      NRZ Write Data+ 14      NRZ Write Data-
15      GND             16      GND
17      NRZ Read Data+  18      NRZ Read Data-
19      GND             20      GND



RLL/MFM  Hard Disk Interface IDC-34 Male, IDC-20 Male
             RLL/MFM IDC-34
pin     assignment      pin     assignment
1       GND             2       Head Sel 8
3       GND             4       Head Sel 4
5       GND             6       Write Gate
7       GND             8       Seek Complete
9       GND             10      Track 0
11      GND             12      Write Fault
13      GND             14      Head Sel 1
15      GND             16      (reserved)
17      GND             18      Head Sel 2
19      GND             20      Index
21      GND             22      Ready
23      GND             24      Step
25      GND             26      Drive Sel 1
27      GND             28      Drive Sel 2
29      GND             30      Drive Sel 3
31      GND             32      Drive Sel 4
33      GND             34      Direction In

             RLL/MFM IDC-20
pin     assignment      pin     assignment
1       Drive Selected  2       GND
3       (reserved)      4       GND
5       (reserved)      6       GND
7       (reserved)      8       GND
9       (reserved)      10      (reserved)
11      GND             12      GND
13      Write Data+     14      Write Data-
15      GND             16      GND
17      Read Data+      18      NRZ Read Data-
19      GND             20      GND


VGA DB15-S Female DB9 Female
15-pin  9-pin   assignment
1       1       Red
2       2       Green
3       3       Blue
4       -       Monitor ID bit 2
5       -       N/C
6       6       GND (red return)
7       7       GND (green return)
8       8       GND (blue return)
9       -       N/C
10      -       GND
11      -       Monitor ID bit 0
12      -       Minitor ID bit 1
13      4       Horizontal Sync
14      5       Vertical Sync
15      -       N/C

Monitor ID bit 0: reserved
Monitor ID bit 1: GND = mono, OPEN = color
Monochrome monitors use the green signal


CGA DB9 Female
pin   assignment
1     GND
2     GND
3     Red
4     Green
5     Blue
6     Intensity
7     (reserved)
8     Horizontal Sync
9     Vertical Sync


EGA DB9 Female
pin   assignment
1     GND
2     Secondary Red
3     Primary Red
4     Primary Green
5     Primary Blue
6     Secondary Green / Intensity
7     Secondary Blue / Mono Video
8     Horizontal Drive
9     Vertical Drive


     ISA Bus Connector              EISA Bus Connector
     -----------------              ------------------
Back Side       Component Side  Back Side       Component Side
pin assignment |pin assignment |pin assignment |pin assignment
B1  GND        |A1  CHCHK#     |F1  GND        |E1  CMD#
B2  Reset DRV  |A2  SD7        |F2  +5V        |E2  START#
B3  +5V        |A3  SD6        |F3  +5V        |E3  EXRDY
B4  IRQ9       |A4  SD5        |F4  ---        |E4  EX32#
B5  -5V        |A5  SD4        |F5  ---        |E5  GND
B6  DRQ2       |A6  SD3        |F6  ACCESS KEY |E6  ACCESS KEY
B7  -12V       |A7  SD2        |F7  ---        |E7  EX16#
B8  NOWS#      |A8  SD1        |F8  ---        |E8  SLBURST#
B9  +12V       |A9  SD0        |F9  +12V       |E9  MSBURST#
B10 GND        |A10 CHRDY      |F10 M/IO#      |E10 W/R#
B11 SMWTC#     |A11 AEN        |F11 LOCK#      |E11 GND
B12 SMRDC#     |A12 SA19       |F12 (reserved) |E12 (reserved)
B13 IOWC#      |A13 SA18       |F13 GND        |E13 (reserved)
B14 IORC#      |A14 SA17       |F14 (reserved) |E14 (reserved)
B15 DACK3#     |A15 SA16       |F15 BE3#       |E15 GND
B16 DRQ3       |A16 SA15       |F16 ACCESS KEY |E16 ACCESS KEY
B17 DACK1#     |A17 SA14       |F17 BE2#       |E17 BE1#
B18 DRQ1       |A18 SA13       |F18 BE0#       |E18 LA31#
B19 REFRESH#   |A19 SA12       |F19 GND        |E19 GND
B20 BCLK       |A20 SA11       |F20 +5V        |E20 LA30#
B21 IRQ7       |A21 SA10       |F21 LA29#      |E21 LA28#
B22 IRQ6       |A22 SA9        |F22 GND        |E22 LA27#
B23 IRQ5       |A23 SA8        |F23 LA26#      |E23 LA25#
B24 IRQ4       |A24 SA7        |F24 LA24#      |E24 GND
B25 IRQ3       |A25 SA6        |F25 ACCESS KEY |E25 ACCESS KEY
B26 DACK2#     |A26 SA5        |F26 LA16       |E26 LA15
B27 T/C        |A27 SA4        |F27 LA14       |E27 LA13
B28 BALE       |A28 SA3        |F28 +5V        |E28 LA12
B29 +5V        |A29 SA2        |F29 +5V        |E29 LA11
B30 OSC        |A30 SA1        |F30 GND        |E30 GND
B31 GND        |A31 SA0        |F31 LA10       |E31 LA9

                               |H1  LA8        |G1  LA7
D1  M16#       |C1  SBHE#      |H2  LA6        |G2  GND
D2  IO16#      |C2  LA23       |H3  LA5        |G3  LA4
D3  IRQ10      |C3  LA22       |H4  +5V        |G4  LA3
D4  IRQ11      |C4  LA21       |H5  LA2        |G5  GND
D5  IRQ12      |C5  LA20       |H6  ACCESS KEY |G6  ACCESS KEY
D6  IRQ15      |C6  LA19       |H7  D16        |G7  D17
D7  IRQ14      |C7  LA18       |H8  D18        |G8  D19
D8  DACK0#     |C8  LA17       |H9  GND        |G9  D20
D9  DRQ0       |C9  MRDC#      |H10 D21        |G10 D22
D10 DACK5#     |C10 MWTC#      |H11 D23        |G11 GND
D11 DRQ5       |C11 SD8        |H12 D24        |G12 D25
D12 DACK6#     |C12 SD9        |H13 GND        |G13 D26
D13 DRQ6       |C13 SD10       |H14 D27        |G14 D28
D14 DACK7#     |C14 SD11       |H15 ACCESS KEY |G15 ACCESS KEY
D15 DRQ7       |C15 SD12       |H16 D29        |G16 GND
D16 +5V        |C16 SD13       |H17 +5V        |G17 D30
D17 MASTER16#  |C17 SD14       |H18 +5V        |G18 D31
D18 GND        |C18 SD15       |H19 MAKx       |G19 MREQx


VESA Standard Feature Connector
pin     assignment      pin     assignment
1       PB              2       PG
3       PR              4       PI
5       SB              6       SG
7       SR              8       SI
9       Dot Clock       10      Blank
11      HSync           12      VSync
13      GND             14      GND
15      GND             16      GND
17      Ext Video Sel   18      Ext Sync Sel
19      Ext DotClock Sel20      N/C
21      GND             22      GND
23      GND             24      GND
25      N/C             26      N/C


Null Modem:
Connector 1 to  Connector 2
DTR             DSR/DCD
DSR/DCD         DTR
RTS             CTS
CTS             RTS
TXD             RXD
RXD             TXD
GND             GND


Bidirectional ("Laplink") Parallel Cable DB-25 male to DB-25 male
Connector 1 to Connector 2
2		15
3		13
4		12
5		10
6		11
10		5
11		6
12		4
13		3
15		2
The remainder connect directly through.


30 pin Fast Page Mode SIMM  256kx8 256kx9 1Mx8 1Mx9 4Mx8 4Mx9
pin     assignment|pin  assignment|pin  assignment|pin  assignment
1       Vcc       |9       Gnd    |17      A8     |25      DQ7
2       -CAS      |10      DQ2    |18      A9     |26      QP
3       DQ0       |11      A4     |19      A10    |27      -RAS
4       A0        |12      A5     |20      DQ5    |28      -CASP
5       A1        |13      DQ3    |21      -WE    |29      DP
6       DQ1       |14      A6     |22      Gnd    |30      Vcc
7       A2        |15      A7     |23      DQ6
8       A3        |16      DQ4    |24      N/C

Notes:
QP, CASP and DP are N/C on all x8 bit modules
a9 is a N/C on 256k modules
a10 is a N/C on 256k and 1M modules


72 pin Fast Page Mode SIMM  256k/512k/1M/2M/4M/8M x 32/36 bit
pin     assignment|pin  assignment|pin  assignment|pin  assignment
1       Gnd       |19      A10    |37      MP1    |55      DQ11
2       DQ0       |20      DQ4    |38      MP3    |56      DQ27
3       DQ16      |21      DQ20   |39      Gnd    |57      DQ12
4       DQ1       |22      DQ5    |40      -CAS0  |58      DQ28
5       DQ17      |23      DQ21   |41      -CAS2  |59      Vcc
6       DQ2       |24      DQ6    |42      -CAS3  |60      DQ29
7       DQ18      |25      DQ22   |43      -CAS1  |61      DQ13
8       DQ3       |26      DQ7    |44      -RAS0  |62      DQ30
9       DQ19      |27      DQ23   |45      -RAS1  |63      DQ14
10      Vcc       |28      A7     |46      N/C    |64      DQ31
11      N/C       |29      N/C    |47      -WE    |65      DQ15
12      A0        |30      Vcc    |48      N/C    |66      N/C
13      A1        |31      A8     |49      DQ8    |67      PD1
14      A2        |32      A9     |50      DQ24   |68      PD2
15      A3        |33      -RAS3  |51      DQ9    |69      PD3
16      A4        |34      -RAS2  |52      DQ25   |70      PD4
17      A5        |35      MP2    |53      DQ10   |71      N/C
18      A6        |36      MP0    |54      DQ26   |72      Gnd

Notes:
MP0,MP1,MP2,MP3 are N/C on all x32 bit modules
a9 is a N/C on 256k and 512k modules
a10 is a N/C on 256k, 512k, 1M and 4M modules
RAS1/RAS3 are N/C on 256k, 1M and 4M modules


SCSI Connector Pinouts (Single Ended) IDC-50 Male
pin     assignment|pin  assignment|pin  assignment|pin  assignment
01      GND       |02     -DB0    |27     GND     |28     GND
03      GND       |04     -DB1    |29     GND     |30     GND
05      GND       |06     -DB2    |31     GND     |32     -ATN
07      GND       |08     -DB3    |33     GND     |34     GND
09      GND       |10     -DB4    |35     GND     |36     -BSY
11      GND       |12     -DB5    |37     GND     |38     -ACK
13      GND       |14     -DB6    |39     GND     |40     -RST
15      GND       |16     -DB7    |41     GND     |42     -MSG
17      GND       |18     -DBP    |43     GND     |44     -SEL
19      GND       |20     GND     |45     GND     |46     -C/D
21      GND       |22     GND     |47     GND     |48     -REQ
23      GND       |24     GND     |49     GND     |50     -I/O
25      (open)    |26     TERMPWR


SCSI Connector Pinouts (Differential) IDC-50 Male
pin     assignment|pin  assignment|pin  assignment|pin  assignment
01      (open)    |02     GND     |27     GND     |28     GND
03      +DB0      |04     -DB0    |29     +ATN    |30     -ATN
05      +DB1      |06     -DB1    |31     GND     |32     GND
07      +DB2      |08     -DB2    |33     +BSY    |34     -BSY
09      +DB3      |10     -DB3    |35     +ACK    |36     -ACK
11      +DB4      |12     -DB4    |37     +RST    |38     -RST
13      +DB5      |14     -DB5    |39     +MSG    |40     -MSG
15      +DB6      |16     -DB6    |41     +SEL    |42     -SEL
17      +DB7      |18     -DB7    |43     +C/D    |44     -C/D
19      +DBP      |20     -DBP    |45     +REQ    |46     -REQ
21      DIFFSENS  |22     GND     |47     +I/O    |48     -I/O
23      GND       |24     GND     |49     GND     |50     GND
25      TERMPWR   |26     TERMPWR


PCI Cards Universal/3.3V/5V and 32/64 bit
pin assignment |pin assignment |pin assignment |pin assignment
B1  -12V       |A1   TRST#     |B48  AD[10]    |A48  Ground
B2  TCK        |A2  +12V       |B49 Ground     |A49 AD[09]
B3  Ground     |A3  TMS        |B50 (KEYWAY2)  |A50 (KEYWAY2)
B4  TDO        |A4  TDI        |B51 (KEYWAY2)  |A51 (KEYWAY2)
B5  +5V        |A5  +5V        |B52 AD[08]     |A52 C/BE[0]#
B6  +5V        |A6  INTA#      |B53 AD[07]     |A53 +3.3V
B7  INTB#      |A7  INTC#      |B54 +3.3V      |A54 AD[06]
B8  INTD#      |A8  +5V        |B55 AD[05]     |A55 AD[04]
B9  PRSNT1#    |A9  reserved   |B56 AD[03]     |A56 Ground
B10 reserved   |A10 +Vi/o      |B57 Ground     |A57 AD[02]
B11 PRSNT2#    |A11 reserved   |B58 AD[01]     |A58 AD[00]
B12 (KEYWAY1)  |A12 (KEYWAY1)  |B59 Vi/o       |A59 +Vi/o
B13 (KEYWAY1)  |A13 (KEYWAY1)  |B60 ACK64#     |A60 REQ64#
B14 reserved   |A14 reserved   |B61 +5V        |A61 +5V
B15 Ground     |A15 RST#       |B62 +5V        |A62 +5V
B16 CLK        |A16 Vi/o       |B63 reserved   |A63 Ground
B17 Ground     |A17 VNT#       |B64 Ground     |A64 C/BE[7]#
B18 REQ#       |A18 Ground     |B65 C/BE[6]#   |A65 C/BE[5]#
B19 +Vi/o      |A19 reserved   |B66 C/BE[4]#   |A66 +Vi/o
B20 AD[31]     |A20 AD[30]     |B67 Ground     |A67 PAR64
B21 AD[29]     |A21 +3.3V      |B68 AD[63]     |A68 AD[62]
B22 Ground     |A22 AD[28]     |B69 AD[61]     |A69 Ground
B23 AD[27]     |A23 AD[26]     |B70 +Vi/o      |A70 AD[60]
B24 AD[25]     |A24 Ground     |B71 AD[59]     |A71 AD[58]
B25 +3.3V      |A25 AD[24]     |B72 AD[57]     |A72 Ground
B26 C/BE[3]#   |A26 IDSEL      |B73 Ground     |A73 AD[56]
B27 AD[23]     |A27 +3.3V      |B74 AD[55]     |A74 AD[54]
B28 Ground     |A28 AD[22]     |B75 AD[53]     |A75 +Vi/o
B29 AD[21]     |A29 AD[20]     |B76 Ground     |A76 AD[52]
B30 AD[19]     |A30 Ground     |B77 AD[51]     |A77 AD[50]
B31 +3.3V      |A31 AD[18]     |B78 AD[49]     |A78 Ground
B32 AD[17]     |A32 AD[16]     |B79 +Vi/o      |A79 AD[48]
B33 C/BE[2]#   |A33 +3.3V      |B80 AD[47]     |A80 AD[46]
B34 Ground     |A34 FRAME#     |B81 AD{45]     |A81 Ground
B35 IRDY#      |A35 Ground     |B82 Ground     |A82 AD[44]
B36 +3.3V      |A36 TRDY#      |B83 AD[43]     |A83 AD[42]
B37 DEVSEL#    |A37 Ground     |B84 AD[41]     |A84 +Vi/o
B38 Ground     |A38 STOP#      |B85 Ground     |A85 AD[40]
B39 LOCK#      |A39 +3.3V      |B86 AD[39]     |A86 AD[38]
B40 PERR#      |A40 SDONE      |B87 AD[37]     |A87 Ground
B41 +3.3V      |A41 SBO#       |B88 +Vi/o      |A88 AD[36]
B42 SERR#      |A42 Ground     |B89 AD[35]     |A89 AD[34]
B43 +3.3V      |A43 PAR        |B90 AD[33]     |A90 Ground
B44 C/BE[1]#   |A44 AD[15]     |B91 Ground     |A91 AD[32]
B45 AD[14]     |A45 +3.3V      |B92 reserved   |A92 reserved
B46 Ground     |A46 AD[13]     |B93 reserved   |A93 Ground
B47 AD[12]     |A47 AD11]      |B94 Ground     |A94 reserved

Notes:
Pins 63-94 exist on 64 bit PCI implementation only
KEYWAY1 exists on Universal and 3.3V boards, they are Ground on 5V boards
KEYWAY2 exists on Universal and 5V boards, they are Ground on 3.3V boards
+Vi/o is 3.3V on 3.3V boards, 5V on 5V boards, and define signal rails
  on the Universal board.


Q) 8.2  *Where are benchmark programs located. What do they mean?

Q) 8.3  What is Plug and Play?

[From: leefi@microsoft.com (Lee Fisher)]

Plug and Play is the name of a technology that lets PC hardware and attached
devices work together automatically, reducing end-user complexity. Plug and
Play technology is implemented in hardware, in operating systems, and in
supporting software such as drivers and in the systemboard's BIOS. Microsoft
will support Plug and Play starting with Windows "Chicago" and Windows NT
"Cairo". Today there is a solution for MS-DOS and Microsoft Windows 3.x using
software from Intel which works with the Plug and Play hardware. There are a
variety of Plug and Play technologies, today including BIOS, ISA cards, SCSI,
IDE CD-ROM, PCMCIA, drivers.

Many specifications are available via anonymous ftp at 
ftp.microsoft.com:/drg/Plug-and-Play.

Email the PlayList@Microsoft.COM alias to get on a list for announcements
regarding new specifications, informations on workshops, etc.

The Compuserve Plug and Play forum (GO PLUGPLAY) is available for technical
support issues regarding hardware and driver design issues.

For more related information, on ftp.microsoft.com, see 
/drg/Plug-and-Play/readme and /drg/Developer-Info/devinfo.zip.

Microsoft is starting a "Plug and Play Hardware Catalog" to showcase Plug and
Play hardware, entries are being accepted for the initial issue. Send hardware
and company information to:
    Plug and Play Catalog
    c/o Microsoft Corporation
    Hardware Vendor Relations Group, building 6
    One Microsoft Way
    Redmond, WA 98053-6399 USA

Q) 8.4  What size should I set my DOS partitions to be?

[From: Mike Long <mike.long@analog.com>]
[Some corrections by: Osmo Ronkanen <ronkanen@cc.helsinki.fi>]

This depends on what cluster size you want.  A smaller cluster size is
better, because a small file takes up a whole cluster if there is even
one byte in it; the leftover space is called "slack."  If you have N
files on your drive, and your cluster size is S bytes, then you can
expect to lose N*S/2 bytes to slack space on the average.

The table below shows the maximum partition size to get clusters of a
given size.  You cannot format a hard drive under DOS with a cluster
size less than 2K.

+-------------------+-----------+-------+
|   Cluster size    | Partition |  FAT  |  Notes
|                   |   size    | type  |
+-------------------+-----------+-------+
|  4K  (4096 bytes) |     16 MB | FAT12 |
|  2K  (2048 bytes) |     32 MB | FAT16 | (DOS versions < 4.0)
|  2K  (2048 bytes) |    128 MB | FAT16 | (DOS versions >= 4.0)
|  4K  (4096 bytes) |    256 MB | FAT16 |
|  8K  (8192 bytes) |    512 MB | FAT16 |
| 16K (16384 bytes) |      1 GB | FAT16 |
| 32K (32768 bytes) |      2 GB | FAT16 |
| 64K (65536 bytes) |      4 GB | FAT16 |
+-------------------+-----------+-------+

Another consideration is backup.  If you backup to tape, you should
have disk partitions smaller than the capacity of a single tape for
ease in backup.

[From: Osmo Ronkanen <ronkanen@cc.helsinki.fi>]

The 32 MB limit actually didn't have anything to do with the
cluster size or FAT it was because the number of sectors in
the partition was stored in boot record as a 16 bit number. 


Q) 8.5  Why won't my system boot from the hard drive?

If you can boot from a floppy and see the files on your hard drive,
then chances are there's something wrong with your MBR (Master Boot
Record) / partition table.  The first thing you should try is: "FDISK
/MBR".  This will fix the master boot record without effecting the
contents of your disk.  If this doesn't work, the next thing to try is
verifying that you have your Primary DOS Partition set active.  To do
this, enter "FDISK" and chose "Set active partition" (usually the
second option) then pick "Primary DOS Partition".  Then exit and
reboot.  This too will not effect the contents of your disk.

The next thing to try is replacing the files required for DOS to boot;
they may have been corrupted or deleted.  To do this, run "SYS C:".
This may or may not be possible as DOS versions before 5.0 required
these files be located at a certain place on your hard drive and that
spot may no longer be available.  Either way, this will not otherwise
effect the contents of your disk.

If neither of these things work, then the next thing to try is
reformatting your hard drive (FORMAT C: /SYS).  Note that this will
erase all of the files on your hard drive, so back up anything you
want to save first!!!  If all three of these suggestions fail, then
chances are you have a more serious problem.

Q) 8.6  How do I clean my computer?

Clean the outside with a damp (not wet) cloth with a mild dish washing
detergent after unplugging the system.  Let it dry completely before
plugging your system in.  Do not clean the inside - computer
components are not susceptible to common house hold dust.  Unless you
have special equipment, you will more likely cause more harm than help
to your computer if you try.

Q) 8.7  *What OS's are available for the PC? Which are free?

[this section being worked on]

Q) 8.8  *How can I transfer files between my PC and a Unix system?

[this section being worked on]

Q) 8.9  What tape backup software is available?

[From: herbst@techunix.technion.ac.il (Herbst OMR)]

 JUMBO TAPE
 ----------
Small. Not many features but does the job. Seems to work only with
Colorado drives.  Latest version is 4.03 and can be found by Archie
jumbo403.zip.

>From "Stan Faullin":
 
Useful DOS program.  Has very basic Backup (total, modified,
selected), Restore, Compare, Erase and Format functions.  Some
versions come with a Windows scheduler, but it will NOT run in the
background in a DOS window.  The compression scheme used in some
previous versions is NOT compatible with their latest release, so you
may not be able to read backups made with version 3.x with version
4.x.  Separate versions of this software are available for their
internal model or the parallel port model.
 
Windows:
 
The Lite version supports both parallel port versions and internal
versions.  The only Windows backup program for a parallel port device,
but only supports the Colorado Trakker unit.  Can run in the
background. Can be found by Archie, cbwlite.exe.
 
>From "gregb@oclflt.den.mmc.com (gregb)":
 
CMS Trakker 250 is supplied with a "generic" software package:
it performs backup, restore, selective backup & restore, compression,
compare. It works with DOS and Windows 3.1. 
For an additional $49.95 ($39?) you can purchase their fancier version.
 
 Central-Point backup
 --------------------
Large with many, many features and confusing directory
selections. Works with most drives.

 Conner Basic 1.0
 ----------------
>From "Moshe Braner   braner@emba.uvm.edu":
useless -- only backs up entire drive.
 
 Conner Basic 1.1
 ----------------
>From: pjk@netcom.com (Phil Koenig)

If you got the low-power backup software bundled in -- Conner Backup
Basics -- and it is V1.0, you are entitled to a free upgrade from Conner.
The new version has an only slightly better addendum to the manual, but
the software now is about as flexible as most users would want -- partial
backup and restore by directory or file, etc.  It has worked well for us,
and I recommend that you ask for your copy.
 
>From: dmiller@im.lcs.mit.edu (Dick and Jill Miller)
 
I emphasize that v1.1 of Conner Backup Basics fixes many of the prior
problems, although its prompts, on-line help and printed documentation 
still deserve improvement.
 
 Conner Exec
 -----------
>From "Moshe Braner   braner@emba.uvm.edu":
 
Very large (2.5 megs for DOS version, windows version even larger).
Did not work with my parallel-port Conner 250meg QIC-80 drive.

 QICstream==Conner "Simply Safe Software Backup Basics version 3.0P"
 -------------------------------------------------------------------
Small and works fine. Works with parallel port Conner drive.
 
 Symantec Norton Backup
 ----------------------
This is included with Norton Desktop for Windows, which is a much
better deal than purchasing Norton Backup for Windows alone.
 
 Symantec Norton Backup for Windows
 ----------------------------------

 GNU-Tar
 -------

Q) 8.10  Why doesn't my new device work as fast as it should?

The performance of individual components in your system are highly
dependent the rest of your system.  For instance, the transfer rate of
drives, usually measured in megabytes per second, can depend on the
drive controller, bus type and OS.  Video card speed, sometime
measured in Winmarks, highly depends on the speed of your main CPU as
well as the OS.  When ever you see a statement on the speed of the
device, be sure to check the small print to determine what type of
system and under what conditions the speed was measured.  Don't be
fooled by benchmark numbers.  Another important corollary of this is
*never* post benchmarks - they offer little to no information for
comparison with other systems.  Benchmarks are only useful for
comparison purposes when run in a controlled environment, and even
then to a limited degree.

Q) 8.11  My drive lists a MTBF of 300,000 hours. Will it really last 34 years?

[From: swwalters@fl51mail.space.honeywell.com  (Steve Walters)]

Mean Time Between Failures (MTBF) is a statistical calculation
indicating the mean time between randomly occurring hardware failures.
Two parameters are necessary to fully describe how long a piece of
hardware will last.  The first parameter is MTBF which is a measure of
frequency in which random hardware failures will occur.  The second
parameter is mean operating life which defines how long the hardware
will last before an anticipated wearout phenomena will occur.  These
two parameters combined together give the true projection of the
'real' life of the drive.  As an example of how these parameters
interrelate, assume your drive has an MTBF of 300,000 hours and an
operating life of 5 years.  The drive will operate uninterrupted until
failure (such as a file server, for example).  This is telling you
that your drive should be very reliable until wearout occurs since the
MTBF greatly exceeds the mean life.  However, after 5 years (on the
average), expect it to fail due to wearout.  In this example, the
actual chances of the drive lasting 3 years is 92%, 4 years is 88%, 5
years is 56% and 6 years is 35%.

Q) 8.12  How do I find pin 1 on my chip/card/cable/connector?

Pin 1 is always marked in one way or another to avoid confusion due to
symmetry (after which known numbering schemes can be used).  The most
important thing to note is that the orientation of the letters or
numbers printed on the chip have absolutely nothing to do with the
actual orientation of the pins.  Never assume that all chips should be
readable from the same angle!

The most obvious marking for pin 1 is a small number '1'.  The first
thing you should do is look very carefully for it.  Ribbon cables are
often marked with a blue or red stripe on pin 1.  Some chips are
marked with a dot, notch or small angled cut in the material just
above pin 1.  Rectangular chips are usually marked with a notch on one
of ends; the first pin counter clockwise from this notch is pin 1.  If
you can't find a marking on the socket or connector, then try looking
at the pads (the holes in the board the socket or connector is
soldered into).  For through-hole devices, pin 1 has a square pad, the
rest should be round.

Q) 8.13  I've run out of power connectors, what can I do?

Assuming your power suply is actually strong enough to power all of
your devices, you can pick up a Y-adapter at your local Radio Shack.

S) 9.0 References

Q) 9.1  What other FAQ's are out there?

The following is a partial list of official FAQs which may be useful
for more information on PC related items.  All of these FAQs are
archived on news.answers, though the frequency in posting and
availability are subject to the maintainers' whims.

If you are retrieving these by anonymous ftp, those items listed with
Archive-name's can be found under the news.answers directory under the
archive name.  The others can be found in their respective hierarchy's
directory under the Subject line's name.  For more information on how
to retrieve these items and how to find other FAQs, refer to the
article "Introduction to the *.answers groups" periodically posted to
news.announce.newusers.

Note: all *.answers groups have been removed from the Newsgroups lines

		------ Hardware Related FAQs ------

Subject: Personal Computer CHIPLIST
From: offerman@einstein.et.tudelft.nl (A. Offerman)
Newsgroups: comp.sys.ibm.pc.hardware.chips
Summary: This list contains the various CPU's and NPX's and their features,
         used in the IBM PC, IBM PC/XT, IBM PC/AT, IBM PS/2 and compatbles,
         and the differences between them.
Archive-name: pc-hardware-faq/chiplist
--
Newsgroups: comp.dcom.modems,comp.sys.ibm.pc.hardware.comm
Subject: MS-Windows COM and Ns16550A UART FAQ
From: rjn@fc.hp.com (Bob Niland)
Summary: Improving Windows 3.x COM performance and reliability.
Archive-name: windows-com-faq
--
Newsgroups: comp.os.msdos.programmer,comp.sys.ibm.pc,comp.sys.ibm.pc.hardware
Subject: The Serial Port, rel. *, part * / *
From: chbl@stud.uni-sb.de (Christian Blum)
--
Subject: Mac & IBM Info-Version *
From: bgrubb@scf.nmsu.edu (Bruce Grubb)
Newsgroups: comp.sys.ibm.pc.hardware,comp.sys.ibm.pc.misc,
	    comp.os.ms-windows.advocacy,comp.os.os2.advocacy,
	    comp.sys.intel,comp.sys.mac.advocacy,comp.sys.mac.hardware
--
Newsgroups: comp.sys.ibm.pc.soundcard
Subject: Generic IBM PC Soundcard FAQ periodic posting
From: plutchak@porter.geo.brown.edu (Joel Plutchak)
Archive-name: PCsoundcards/generic-faq
Summary: Non-product-specific information about IBM PC soundcards
--
Newsgroups: comp.sys.ibm.pc.soundcard,comp.music,rec.music.synth,
	    comp.sys.ibm.pc.hardware
Subject: FAQ: Gravis Ultrasound ("GUS") FAQ v*
From: Matthew E. Bernold <MEB117@psuvm.psu.edu>
Archive-name: PCsoundcards/gravis-ultrasound/faq
Summary: A list of Frequently Asked Questions (and answers) concerning
	 the Gravis Ultrasound (GUS) sound card for IBM PC's. 
--
Newsgroups: comp.sys.mac.apps,comp.sys.mac.misc,comp.sys.mac.system,
	    comp.sys.mac.wanted,comp.sys.mac.hardware
Subject: Introductory Macintosh frequently asked questions (FAQ)
From: erh0362@tesla.njit.edu  (Elliotte Rusty Harold)
Archive-name: macintosh/general-faq
Summary: This document answers a number of the most frequently asked
 questions on Usenet about Macintosh computers.  To avoid wasting
 bandwidth and as a matter of politeness please familiarize yourself
 with this document BEFORE posting.
--
Newsgroups: comp.sys.mac.hardware,comp.sys.mac.misc
Subject: Macintosh PowerPC FAQ
From: Schechter.1@osu.edu
Archive-name: macintosh/PowerPC-FAQ
Summary: This posting contains a list of questions and (often speculative)
         answers about PowerPC and its relation to the Macintosh.
--
Newsgroups: comp.1.sys5.r4,comp.1.pc-clone.32bit,comp.sys.intel,
	    comp.os.linux.announce
Subject: PC-Clone UNIX Hardware Buyer's Guide
From: esr@snark.thyrsus.com (Eric S. Raymond)
Archive-name: pc-1/hardware
Summary: Tips on how and where to buy hardware for your UNIX.

		------ OS Related FAQs ------

Newsgroups: comp.1.questions,comp.1.shell
Subject: Unix - Frequently Asked Questions (Contents) [Frequent posting]
From: tmatimar@empress.com (Ted M A Timar)
Archive-name: 1-faq/faq/contents
--
Newsgroups: comp.1.questions,comp.1.shell
Subject: Unix - Frequently Asked Questions (* / *) Digest [Frequent posting]
From: tmatimar@empress.com (Ted M A Timar)
Archive-name: 1-faq/faq
--
Newsgroups: comp.1.sys5.r4,comp.1.pc-clone.32bit,comp.1.bsd,
	    comp.os.linux.announce
Subject: PC-clone UNIX Software Buyer's Guide
From: esr@snark.thyrsus.com (Eric S. Raymond)
Archive-name: pc-1/software
Summary: A buyer's guide to UNIX versions for PC-clone hardware
--
Newsgroups: comp.os.386bsd.announce
Subject: FAQ: 386BSD/NetBSD Compatible tape drive list
From: Bob Kemp <rsk@ecs.southampton.ac.uk>
--
Newsgroups: comp.os.386bsd.announce
Subject: [comp.os.386bsd] Berkeley Net Release/2 derived BSD for
	 PCs FAQ (Part * of *)
From: burgess@hrd769.brooks.af.mil (Dave Burgess)
Archive-name: 386bsd-faq/part1
--
Newsgroups: comp.os.linux
Subject: ** Linux Documents Explained for Newbies **  Weekly Post
From: jay-m@equinox.unr.edu (J.A. MacDonald)
--
Newsgroups: comp.os.linux.announce
Subject: LILO FAQ, version *
From: almesber@nessie.cs.id.ethz.ch (Werner Almesberger)
--
Newsgroups: comp.os.linux.announce
Subject: Linux FTP and BBS List #* (LONG)
From: Zane H. Healy <healyzh@holonet.net>
--
Newsgroups: comp.os.linux.announce,comp.os.linux
Subject: [comp.os.linux.announce] Guidelines for posting
From: mdw@sunSITE.unc.edu (Matt Welsh)
Archive-name: linux/announce/guide
--
Newsgroups: comp.os.linux.announce,comp.os.linux.admin
Subject: Linux * HOWTO
From: vince@victrola.wa.com (Vince Skahan)
Comment: The following article are currently being posted (archive
	names, in parentheses, are in the "linux/howto" archive
	directory): Electronic Mail (mail); News (news); UUCP (uucp).
Archive-name: linux/howto/mail
--
Newsgroups: comp.os.linux.announce,comp.os.linux.help,comp.os.linux.admin
Subject: Linux * HOWTO
From: mdw@sunsite.unc.edu (Matt Welsh)
Summary: HOWTO on configuration of TCP/IP networking and SLIP under Linux.
Archive-name: linux/howto/networking
--
Newsgroups: comp.os.linux.announce,comp.os.linux.help,comp.os.linux.admin
Subject: Linux HOWTO Index
From: mdw@sunsite.unc.edu (Matt Welsh)
Archive-name: linux/howto/index
 Summary: Index of HOWTO documents about Linux.
--
Newsgroups: comp.os.linux.announce,comp.os.linux.admin
Subject: Linux Ethernet HOWTO
From: Paul Gortmaker <paul@cain.mmtc.rmit.oz.au>
Archive-name: linux/howto/ethernet
--
Newsgroups: comp.os.linux.announce,comp.os.linux.admin
Subject: Linux Printing HOWTO
From: gtaylor@cs.tufts.edu
Archive-name: linux/howto/printing
Summary: HOWTO on printing under Linux
--
Newsgroups: comp.os.linux.announce,comp.os.linux.help
Subject: Linux Frequently Asked Questions with Answers
From: ijackson@nyx.cs.du.edu (Ian Jackson)
Archive-name: linux/faq
Summary: Please read this before posting to comp.os.linux.help.
--
Newsgroups: comp.os.linux.announce,comp.os.linux.help
Subject: Linux INFO-SHEET
From: johnsonm@stolaf.edu
Summary: This posting contains a quick summary of the features and abilities
         of the Linux operating system.  It is a supplement to the
         comp.os.linux FAQ and META-FAQ, and should be read by those
         wishing to learn about and/or install Linux.
Archive-name: linux/info-sheet
--
Newsgroups: comp.os.linux.announce,comp.os.linux.help
Subject: Linux META-FAQ
From: johnsonm@stolaf.edu
Summary: This is a quick summary of the information available about the
         Linux operating system, explaining where other information can
         be found.  This should be read by anyone wishing to install
         Linux, and by anyone who wishes to find other sources for
         information on Linux.
Archive-name: linux/meta-faq
--
Newsgroups: comp.os.linux.announce,comp.os.linux.help,
	    comp.os.linux.development,comp.os.linux.admin,comp.os.linux.misc
Subject: Welcome to the comp.os.linux.* hierarchy!
From: mdw@TC.Cornell.EDU (Matt Welsh)
Archive-name: linux/announce/intro
--
Newsgroups: comp.os.mach
Subject: comp.os.mach Frequently Asked Questions
From: fgray@owlnet.rice.edu (Frederick Earl Gray)
Archive-name: mach-faq
Summary: Answers to questions frequently asked on the USENET newsgroup
         comp.os.mach
--
Newsgroups: comp.os.minix
Subject: Changes to MINIX Frequently Asked Questions
From: overby@plains.nodak.edu (Glen Overby)
--
Newsgroups: comp.os.minix
Subject: Changes to MINIX Information Sheet
From: overby@plains.nodak.edu (Glen Overby)
Summary: Everything you ever wanted to know about Minix on the networks,
 	but never dared to ask!
--
Newsgroups: comp.1.msdos
Subject: Frequently Asked Questions (FAQ) for comp.1.msdos
From: fnx!vpix-faq@uunet.UU.NET (VP/IX FAQ maintainance)
--
Newsgroups: comp.os.msdos.programmer
Subject: comp.os.msdos.programmer FAQ part * of *
From: brown@NCoast.ORG (Stan Brown)
Archive-name: msdos-programmer-faq/part3
--
Newsgroups: comp.os.os2.misc,comp.os.os2.apps
Subject: OS/2 Frequently Asked Questions List Rel. * (* of *)
From: sip1@kimbark.uchicago.edu (Timothy F. Sipples)
Archive-name: os2-faq/user/part1
--
Newsgroups: comp.os.os2.programmer.misc,comp.os.os2.programmer.porting
Subject: FAQ: OS/2 Programming FAQ v*
From: jgarzik@pantera.atl.ga.us (Jeff Garzik)

		------ Windowing System Related FAQs ------

Newsgroups: comp.sources.x
Subject: How to get X sources for free.
From: argv@sun.com (Dan Heller)
--
Newsgroups: comp.windows.x
Subject: X Servers for DOS, Microsoft Windows, OS/2, Macs, Amigas, Atari
From: mccoy@gothamcity.jsc.nasa.gov (Daniel J. McCoy)
--
Newsgroups: comp.windows.x
Subject: comp.windows.x Frequently Asked Questions (FAQ) * / *
From: dbl@visual.com (David B. Lewis)
Summary: useful information about the X Window System
Archive-name: x-faq/part*
--
Newsgroups: comp.windows.x.i386unix,comp.1.pc-clone.32bit,
	    comp.1.bsd,comp.windows.x
Subject: X on Intel-based Unix Frequently Asked Questions [FAQ]
From: steve@ecf.toronto.edu (Steve Kotsopoulos)
Archive-name: Intel-Unix-X-faq
Summary: X options for Intel-based Unix (SYSV/386, 386BSD, Linux, Mach)
--
Newsgroups: comp.os.ms-windows.advocacy,comp.os.ms-windows.apps,
	    comp.os.ms-windows.setup,comp.os.ms-windows.misc,
	    comp.os.ms-windows.nt.setup,comp.os.ms-windows.nt.misc,
	    comp.os.ms-windows.programmer.tools,
	    comp.os.ms-windows.programmer.win32,
	    comp.os.ms-windows.programmer.misc,bit.listserv.win3-l
Subject: INFO: A guide to the Windows newsgroups
From: tomh@metrics.com (Tom Haapanen)
Archive-name: ms-windows/newsgrp.guide
--
Newsgroups: comp.os.ms-windows.apps,comp.os.ms-windows.misc,
	    comp.os.ms-windows.setup,bit.listserv.win3-l
Subject: Windows FAQ: How to get it
From: tomh@metrics.com (Tom Haapanen)
Archive-name: ms-windows/faqwin.how-to
--
Newsgroups: comp.os.msdos.desqview
Subject: DESQview/QEMM Frequently Asked Questions: READ BEFORE POSTING
From: danb@bunt.sps.mot.com
Archive-name: desqview-faq
Summary: FAQ list for the MS-DOS multitasker DESQview and memory manager QEMM

		------ Miscellaneous FAQs ------

Subject: How to find sources
From: jik@security.ov.com (Jonathan I. Kamens)
Newsgroups: comp.sources.wanted,alt.sources.wanted
Archive-name: finding-sources
--
Subject: Standards FAQ
Newsgroups: comp.std.internat,comp.std.misc,comp.protocols.iso
From: unrza3@cd4680fs.rrze.uni-erlangen.de (Markus Kuhn)
Archive-name: standards-faq
Summary: Answers to questions such as what are ISO standards, where can I
         get standards, what are ISO/ITU/ANSI/etc., what standards are
         there relevant to computing, ...? This is a periodic posting in
         comp.protocols.iso, comp.std.misc and comp.std.internat.
--
Subject: PC GAMES FAQ <- Guide To The Gaming World (Part * of *)
From: appelo@dutiba.twi.tudelft.nl (Jurgen Appelo)
Newsgroups: comp.sys.ibm.pc.games.announce,rec.games.misc
Archive-name: PC-games-faq/part1
Summary: This FAQ has answers to common questions and other useful
	 information that all new readers of the comp.sys.ibm.pc.games.*
	 newsgroups should read before posting.
--
Newsgroups: comp.virus
Subject: VIRUS-L/comp.virus Frequently Asked Questions (FAQ)
From: "Kenneth R. van Wyk" <krvw@cert.org>
Archive-name: computer-virus-faq
Summary: This posting contains a list of Frequently Asked Questions,
         and their answers, about computer viruses.  It should be read
         by anyone who wishes to post to VIRUS-L/comp.virus.
--
Newsgroups: misc.forsale
Subject: Welcome to Misc.forsale - Frequently Asked Questions (please read!)
From: murray@sun13.scri.fsu.edu (John Murray)
--
Newsgroups: misc.forsale.computers,misc.forsale.computers.d
Subject: misc.forsale.computers.d FAQ
From: "Peter W. De Bonte" <pwd+@CMU.EDU>
--
Newsgroups: comp.archives.msdos.announce,comp.archives.msdos.d
Subject: comp.archives.msdos.{announce,d} FAQ (Frequently Asked Questions)
From: ts@chyde.uwasa.fi (Timo Salmi)
Archive-name: msdos-archives/faq
--
Newsgroups: comp.archives.msdos.d,comp.binaries.ibm.pc.wanted,
	    comp.os.msdos.apps,comp.sys.ibm.pc.misc
Subject: Useful MSDOS Programs at SIMTEL20 and Garbo (Part * of *)
From: sko@wimsey.bc.ca (Samuel Ko)
Archive-name: msdos-archives/part*
Summary: A list of recommended msdos programs available from major ftp sites
--
Newsgroups: comp.binaries.ibm.pc
Subject: v*inf*: charter, CBIP newsgroups charter (part * / *)
From: cbip@cs.uml.edu (CBIP Moderator)
Archive-name: admin/charter
--
Newsgroups: comp.lang.postscript
Subject: PostScript monthly FAQ v* *-*-* [* of *]
From: jgm@cs.brown.edu (Jonathan Monsarrat)
Summary: Useful facts about the PostScript graphics programming language
Archive-name: postscript/faq/part*
--
Newsgroups: comp.periphs.scsi
Subject: comp.periphs.scsi FAQ
From: vail@tegra.com (Johnathan Vail)
Archive-name: scsi-faq
Summary: This posting contains a list of Frequently Asked
             Questions (and their answers) about SCSI.  It
             should be read by anyone who wishes to post to the
             comp.periphs.scsi newsgroup.
--
Newsgroups: comp.protocols.nfs,comp.protocols.tcp-ip
Subject: (PC)NFS & related topics FAQ [part * / *]
From: rawn@lead.aichem.arizona.edu (Rawn Shah)
Archive-name: pcnfs-faq/part1
Summary: This is the FAQ list about PC & Macintosh based NFS & TCP/IP
 	 products for readers of comp.protocols.nfs &
 	 comp.protocols.tcp-ip.ibmpc
--
Newsgroups: comp.protocols.tcp-ip.ibmpc
Subject: comp.protocols.tcp-ip.ibmpc Frequently Asked Questions (FAQ)
From: aboba@netcom.com (Bernard Aboba)
Archive-name: ibmpc-tcp-ip
Summary: Frequently Asked Questions (and answers) about TCP/IP on
                   PC-compatible computers.
--
Newsgroups: alt.cd-rom,comp.multimedia
Subject: alt.cd-rom FAQ
From: rab@cdrom.com
Summary: Frequently asked questions about CD-ROMs
Archive-name: cdrom-faq
--
Newsgroups: alt.emulators.ibmpc.apple2
Subject: alt.emulators.ibmpc.apple2 Frequently Asked Questions (FAQ)
From: vera@anna.stanford.edu (James Vera)
Archive-name: emulate-apple2-faq
Summary: This posting contains a list of Frequently Asked Questions
         (and their answers) about emulating Apple ][ computers (or //e
         ...) on other computers (like PCs or UNIX boxes).  Please
         read before posting questions.

Q) 9.2  What do the industry acronyms stand for?

[From ralf@wpi.wpi.edu (Ralph Valentino)]

This is a list of 280+ acronyms which commonly come up in discussion
of hardware.  It does not contain abbreviations or names that don't
stand for anything, nor does it attempt to explain exactly what the
technology does, where it can be found, nor even how to use it in a
sentence.  So, is it completely useless?  Well, sometimes just knowing
what an acronym stands for is enough to tell you what people are
talking about or where to go to get more information about it.

If anyone has any additions, comments, or corrections, please forward
them to me directly.  Keep in mind that I have tried to avoid software
topics except where they overlap with hardware ones, so don't bother
telling me what BASIC stands for as it is outside the scope of this
list.

AC	Alternating Current
AE	Applications Engineer
AFS	Andrew File System
AI	Artificial Intelligence
ALU	Arithmetic-Logic Unit
AM	Amplitude Modulated
AMD	Advanced Micro Devices, Inc.
AMI	American Megatrends Inc.
ANSI	American National Standards Institute
ASCII	American Standard Code for Information Interchange
ASIC	Application Specific Integrated Circuit
ASPI	Advanced SCSI Programming Interface
AT	Advanced Technology
ATDM	Asynchronous Time Division Multiplexing
ATM	Asynchronous Transfer Mode
AUI	Attached Unit Interface
BBS	Bulletin Board System
BCC	Block Check Character
BCD	Binary Coded Decimal
BE	Back End
BiCMOS	Bipolar Complementary Metal-Oxide Semiconductor
BIOS	Basic Input / Output System
BNC	Bayonet Nut Connector
BPS/bps	Bytes/bits Per Second
BSC	Binary Synchronous Communications
BSD	Berkeley Standard Distribution
BTU	British Thermal Units
CAD	Computer Aided Design
CAM	Computer Aided Manufacturing
CAM	Content Addressable Memory
CAS	Column Address Strobe
CBX	Common Branch eXtender
CCD	Charge Coupled Device
CCITT	Consultative Committee of International Telephony and Telegraphy
CD	Carrier Detect
CDDI	Copper Distributed Data Interface
CDROM	Compact Disk Read Only Memory
CGA	Color Graphics Adaptor
CISC	Complex Instruction-Set Computer
CLA	Carry Lookahead Adder
CMOS	Complementary Metal-Oxide Semiconductor
CP/M	Control Program / Monitor
CPI	Clocks Per Instruction
CQFP	Ceramic Quad-FlatPack
CPU	Central Processing  Unit
CR	Carriage Return
CRC	Cyclical redundancy check
CRQ	Command Response Queue
CRT	Cathode Ray Tube
CS	Chip Select
CSMA	Carrier Sense Multiple-Access
CSMA/CD	Carrier Sense Multiple-Access with Collision Detect
CSR	Command Status Register
CTS	Clear To Send
DAT	Digital Audio Tape
DC	Direct Current
DCD	Data Carrier Detect
DCE	Data Circuit-terminating Equipment
DD	Double Density
DEC	Digital Equipment Corporation
DES	Data Encryption Standard
DID	Direct Inward Dial
DIN	Deutsche Industrie Norm
DIP	Dual-In-line Package
DIS	Draft International Standard
DMA	Direct Memory Access
DOS	Disk Operating System
DPE	Data Parity Error
DPSK	Differential Phase Shift Keying
DRAM	Dynamic Random Access Memory
DS	Double Sided
DSP	Digital Signal Processor
DSR	Data Set Ready
DTC	Data Terminal Controller
DTE	Data Terminating Equipment
DTMF	Dual-Tone MultiFrequency
DTR	Data Terminal Ready
EBCDIC	Extended Binary Coded Decimal Interchange Code
ECC	Error Correction Code
ECL	Emitter-Coupled Logic
ECO	Engineering Change Order
ECU	EISA Configuration Utility
EEPROM	Electrically Erasable Programmable Read-Only Memory
EGA	Enhanced Graphics Adaptor
EIA	Electronic Industries Association
EISA	Enhanced Industry Standard Architecture
EMI	Electro-Magnetic Interference
EMF	Electro-Magnetic Force
EMS	Expanded Memory Specification
EOF	End Of File
EOL	End Of Line
EOS	Electrical Overstress
EPROM	Erasable Programmable Read-Only Memory
ESD	Electro-Static Discharge
ESDI	Enhanced Small Devices Interface
FAT	File Allocation Table
FCC	Federal Communications Commission
FDD	Fixed Disk Drive (or Floppy Disk Drive)
FDDI	Fiber Distributed Data Interface
FDM	Frequency Division Multiplexing
FDX	Full-Duplex Transmission
FE	Front End
FEP	Front End Processor
FF	Form Feed
FIFO	First-In First-Out
FILO	First-In Last-Out (same as LIFO)
FM	Frequency Modulation
FPGA	Field Programmable Gate Array
FPU	Floating Point Unit
FRU	Field-Replaceable Unit
FSF	Free Software Foundation
FSK	Frequency Shifty Keying
FTP	File Transfer Program
GAS	Gallium Arsenide
GFLOPS	Billions (10^9) of FLOating Point Operations Per Second ("GigaFlops")
GNU	Gnu's Not Unix
GUI	Graphical User Interface
HD	High Density
HDD	Hard Disk Drive
HDX	Half-Duplex Transmission
HFS	Hierarchical File System
HPFS	High Performance File System
HS	Helical Scan
I/O	Input / Output
IBM	International Business Machines Corp.
IC	Integrated Circuit
IDC	Insulation Displacement Connector
IDE	Integrated Device Electronics
IEEE	Institute of Electrical and Electronic Engineers
IMP	Interface Message Processor
IPC	InterProcess Communication
IRQ	Interrupt ReQuest
ISA	Industry Standard Architecture
ISDN	Integrated Services Digital Network
ISO	International Standards Organization
JFS	Journaled File System
kVA	KiloVolt-Amps
LAN	Local Area Network
LAPM	Link Access Procedure M
LCD	Liquid Crystal Display
LED	Light Emitting Diode
LF	Line Feed
LIM	Lotus/Intel/Microsoft Expanded Memory Manager Specification
LRU	Least-Recently Used
LSB/lsb	Least Significant Byte/bit
LSI	Large Scale Integration
LUN	Logical Unit Number
MAN	Metropolitan Area Network
MB/Mb	Mega Bytes/bits
MBR	Master Boot Record
MCA	Micro Channel Architecture
MCGA	Multi-Color Graphics Array
MCM	Multi-Chip Module
MFLOPS	Millions of FLOating Point Operations per Second ("MegaFlops")
MFM	Modified Frequency Modulated
MHz	MegaHertz
MICR	Magnetic Ink Character Recognition
MIDI	Musical Instrument Data Interface
MIMD	Multiple-Instruction Multiple-Data
MIPS	Millions of Instructions per Second
MISD	Multiple-Instruction Single Data
MMU	Memory Management Unit
MNP	Microcom Network Protocol
MODEM	MOdulator / DEModulator
MOPS	Millions of Operations Per Second
MOS	Metal-Oxide Semiconductor
MP	MultiProcessor
MPP	Massively Parallel Processor
MSB/msb	Most Significant Byte/bit
MSDOS	Microsoft Disk Operating System
MSI	Medium Scale Integration
MTBF	Mean Time Between Failure
N/C	No-Connect
NBS	National Bureau of Standards
NEMA	National Electrical Manufacturers Association
NFS	Network File System
NFU	Not-Frequently Used
NMI	Non-Maskable Interrupt
NMOS	Negatively doped Metal-Oxide Semiconductor
NOP	No OPeration
NRU	Not-Recently Used
NSF	National Science Foundation
NVRAM	NonVolatile Random Access Memory
OCR	Optical Character Recognition
ODI	Open Datalink Interface
OEM	Original Equipment Manufacturer
OS	Operating System
OSF	Open Software Foundation
OSI	Open Systems Interconnect
PAL/PLA	Programmable Array Logic (Logic Array)
PB	Push Button
PBX	Private Branch eXtender
PC	Personal Computer, Program Counter
PCB	Printed Circuit Board
PCI	Peripheral Component Interconnect
PCM	Pulse Code Modulation
PCMCIA	Personal Computer Memory Card International Association
PE	Processor Element
PFF	Page Fault Frequency
PGA	Pin Grid Array
PIC	Programmable Interrupt Controller
PIO	Programmed Input/Output
PLCC	Plastic Leaded Chip Carrier
PLL	Phase Locked Loop
PM	Preventive Maintenance
PMOS	Positively doped Metal-Oxide Semiconductor
POST	Power On Self Test
PPP	Point-to-Point Protocol
PQFP	Plastic Quad-FlatPack
PROM	Programmable Read-Only Memory
PSTN	Public Switched Telephone Network
PTE	Page Table Entry
QAM	Quadrature Amplitude Modulation
QFP	Quad-FlatPack
QIC	Quarter Inch Cartridge
RAID	Redundant Arrays of Inexpensive Disks
RAM	Random Access Memory
RAMDAC	Random Access Memory Digital to Analog Converter
RAS	Row Address Strobe
RCA	Radio Corporation of America
RCC	Routing Control Center
RFC	Request For Comments
RFI	Radio Frequency Interference
RI	Ring Indicator
RISC	Reduced Instruction-Set Computer
RLL	Run Length Limited
RMM	Read Mostly Memory (same as EPROM)
RMS	Root Mean Squared
RMW	Read Modify Write
ROM	Read-Only Memory
RPC	Remote Procedure Call
RPM	Rotations Per Minute
RTC	Real Time Clock
RTS	Request To Send
SAM	Sequential Access Memory
SASI	Shugart Associates Standard Interface
SCSI	Small Computer Systems Interface
SD	Single Density
SDLC	Synchronous Data Link Control
SDLC	Synchronous Data Link Control
SE	Systems Engineer
SIMD	Single-Instruction Multiple-Data
SIMM	Single Inline Memory Module
SIPP	Single Inline Pinned Package
SISD	Single-Instruction Single-Data
SLIP	Serial Line Internet Protocol
SMD	Surface Mount Device
SMT	Surface Mount Technology
SNA	System Network Architecture
SNR	Signal to Noise Ratio
SO/SOL	Small OutLine
SOIC	Small Outline Integrated Circuit
SPOOL	Simultaneous Peripheral Operation On Line
SPT	Sectors Per Track
SPU	Single Processor Unit
SRAM	Static Random Access Memory
SS	Single Sided
STDM	Synchronous Time Division Multiplexing
STN	Super Twisted Nematic
STU	Streaming Tape Unit
SVGA	Super Video Graphics Array
TCM	Trellis Code Modulation
TCP/IP	Transmission Control Protocol / Internet Protocol
TDM	Time Division Multiplexing
TI	Texas Instruments
TIA	Telecomm. Industry Assocation
TLB	Translation-Lookaside Buffer
TPI	Tracks Per Inch
TSR	Terminate and Stay Resident
TTL	Transistor-Transistor Logic
TUV	Technischer Ueberwachuags Verein
UART	Universal Asynchronous Receiver/Transmitter
UDP	User Datagram Protocol
UMB	Upper Memory Block
UPS	Uninterruptible Power Supply
USL	Unix System Labs
UUCP	Unix to Unix Copy Program
VCR	Video Cassette Recorder
VESA	Video Enhanced Standards Association
VGA	Video Graphics Array
VLB	VESA Local Bus
VLIW	Very Long Instruction Word
VLSI	Very Large Scale Integration
VM	Virtual Memory
VME	Versa Module Eurocard
VRAM	Video Random Access Memory
VTR	Video Tape Recorder
WAN	Wide Area Network
WATS	Wide Area Telephone Service
WD	Western Digital
WORM	Write-Once Read-Many
WS	Wait State
XGA	eXtended Graphics Array
XMS	Extended Memory Specification
XOR	Exclusive-Or
XT	eXtended Technology
ZIF	Zero Insertion Force

Q) 9.3  Where can I get the ISA/EISA/VLB/PCI/etc specs?

[From: cls@truffula.sj.ca.us (Cameron Spitzer):

_EISA Specification_
BCPR Services Inc.
POB 11137
Spring TX 77391
(713)251-4832

This book *specifies* the Extended ISA.  The expansion slot and
motherboard IO deviced are described.  Also, a file format is defined
for describing the configuration of an EISA-compatible Adapter.

[From: comins@tecrus.enet.dec.com]

Questions concerning PCI specifications or membership can be sent to:

PCI Special Interest Group
M/S JF2-51
5200 N.E. Elam Young Parkway
Hillsboro, Oregon 97124-6497
(503)696-6111

Non-members of the PCI SIG may request a PCI Local Bus Specification for
$25 + shipping costs by calling:
1-800-433-5177

[From: herbst@techunix.technion.ac.il (Herbst OMR)]

Quarter-Inch Cartridge Drive Standards, Inc.
311 East Carrillo Street
Santa Barbara, California 93101
Telephone (805) 963-3853
Fax       (805) 962-1541

Video Electronics Standards Association
2150 North First St.
Suite 440
San Jose, CA  95131-2020
Telephone: (408) 435-0333


Q) 9.4  What books are available for the PC architecture?

Edward Solari
_ISA & EISA_ Theory and Operation
Annabooks, San Diego CA USA
ISBN 0-929392-15-9

This is an excellent book on the EISA and ISA architectures.
Everything you need to know to make your own card, from timing to ECU
config files.

Tom Shanley
_EISA System Architecture_
MindShare, Inc, Richardson, TX USA
ISBN 1-881609-03-0

This book is good for an overview of the EISA and, in part, ISA
systems.  It doesn't go into enough detail to design boards from, but,
as a quote from the sleeve says "The co-ops in the group have found
them to be especially useful."

Tom Shanley
_PCI System Architecture_
MindShare, Inc, Richardson, TX USA
ISBN 1-881609-06-5

[From: cls@truffula.sj.ca.us (Cameron Spitzer):

Edward Solari
_AT Bus Design_
Annabooks, San Diego CA USA
ISBN 0-929392-08-6

This book describes the expansion slot which appeared in IBM's
Personal Computer AT.  This bus is now known as the Industry Standard
Architecture Bus, or just ISA.  It gives enough functional and timing
detail for the hardware designer to ensure a new Adapter's
compatibility.  It does not discuss any of the defacto-standard
Adapters, peripherals, or BIOS features, and gives only an overview of
the memory and IO layout.  The timing details are for the nominal 8
MHz bus clock.  Recent practice of drastically increasing this clock
rate is not discussed.

[From: Shaun Burnett (burnesa@cat.com)]

Scott Mueller
_Upgrading and Repairing PCs, 2nd ed._
QUE
ISBN 0-88022-856-3

I've found the following book to be an excellent reference on the PC.
It discusses the IBM PC family and various peripherals.  The book is
written so that the novice user will find this book of use.  Those
that deal with PCs on a lower level will appreciate the numerous
tables that contains information on such topics as serial port
pin-outs, bus connection labels, and I/O ports addresses.

===============
Ralph Valentino   (ralf@chpc.org)  (ralf@wpi.wpi.edu)
Hardware Engineer,  Worcester  Polytechnic  Institute
Center for High Performance Computing, Marlborough MA

From ankh.iia.org!babbage.ece.uc.edu!news.kei.com!MathWorks.Com!news.duke.edu!news-feed-1.peachnet.edu!paperboy.wellfleet.com!noc.near.net!chpc.chpc.org!chpc.chpc.org!not-for-mail Sun Aug 14 17:59:35 1994
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From: ralf@chpc.org (Ralph Valentino)
Newsgroups: comp.sys.ibm.pc.hardware.video,comp.sys.ibm.pc.hardware.comm,comp.sys.ibm.pc.hardware.storage,comp.sys.ibm.pc.hardware.cd-rom,comp.sys.ibm.pc.hardware.systems,comp.sys.ibm.pc.hardware.networking,comp.sys.ibm.pc.hardware.chips,comp.sys.ibm.pc.hardware.misc,comp.answers,news.answers
Subject: comp.sys.ibm.pc.hardware.* Frequently Asked Questions (FAQ) Part 5/5
Followup-To: comp.sys.ibm.pc.hardware.misc
Date: 12 Aug 1994 02:08:10 -0400
Organization: Center For High Performance Computing
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Approved: news-answers-request@MIT.EDU
Distribution: world
Expires: 11 Sep 1994 00:00:00 GMT
Message-ID: <32f3ka$6it@chpc.chpc.org>
Reply-To: ralf@wpi.edu
NNTP-Posting-Host: localhost.chpc.org
Summary: This is a monthly posting containing a list of Frequently
	 Asked Questions (and their answers) pertaining to hardware
	 and IBM PC clones.  It should be read by anyone who wishes
	 to post to any group in the comp.sys.ibm.pc.hardware.*
	 hierarchy.
Xref: ankh.iia.org comp.sys.ibm.pc.hardware.video:9604 comp.sys.ibm.pc.hardware.comm:3136 comp.sys.ibm.pc.hardware.storage:7355 comp.sys.ibm.pc.hardware.cd-rom:4236 comp.sys.ibm.pc.hardware.systems:4217 comp.sys.ibm.pc.hardware.networking:2186 comp.sys.ibm.pc.hardware.chips:7715 comp.sys.ibm.pc.hardware.misc:7819 comp.answers:3112 news.answers:9229

Archive-name: pc-hardware-faq/part5
Last-modified: 1994/08/10
Version: 1.7


Q) 9.5  What books are available on network programming?

[From: p00736@psilink.com (Frederick J. Ingham)]

In response to several queries, the following books are excellent resources 
on network programming:

Roetzheim, William H., A C Programmers's Guide to the IBM Token Ring, 
Prentice Hall, Englewood Cliffs, New Jersey, 1991

Nance, Barry, Network Programming in C, QUE Corporation, Carmel, IN, 1990. 
(covers Netware NCP, IPX/SPX, and NetBIOS)

Schwaderer, W. David, C Programmer's Guide to NetBIOS, IPX, and SPX, SAMS 
Publishing, Carmel, IN, 1992.

Davis, Ralph, Windows Network Programming 'How to survive in a World of 
Windows, DOS, and Networks', Addison Wesley, Reading, Massachusetts, 1993.
(covers NetBIOS, IPX/SPX, VINES Sockets, TCP/IP, Windows Sockets, Several NOS 
APIs, Mailslots, Named Pipes, etc.)

Comer, Douglas E., Internetworking with TCP/IP, Client - Server Programming 
and Applications, Vol III, Prentice Hall, Englewood Cliffs, New Jersey, 1993.

IBM, Local Area Network, Technical Reference, Document SC30-3383-03, IBM 
Corporation, 1990.
(covers the IBM Token Ring Direct Interface, DLC, and NetBIOS programming)

IBM, Operating System/2, Local Area Network Server, Application Programmer's 
Reference, Document S04G-1046-00, IBM Corporation, 1991.
(covers the IBM LAN Server API and Microsoft LAN Manager API)

Microsoft, LAN Manager Programmer's Reference, Microsoft Press, One Microsoft 
Way, Redmond, Washington, 1990.
(covers the Microsoft LAN Manager API)

Microsoft, Intel, Microsoft Networks/OpenNET, File Sharing Protocol, v2.0, 
1988.
Microsoft, Microsoft Networks, SMB File Sharing Protocol Extensions v2.0, 
1988.
Microsoft, Microsoft Networks, SMB File Sharing Protocol Extensions v3.0, 
1989.
(all of the above cover the Server Message Block protocol used by Microsoft 
LAN Manager and IBM LAN Server.  they are available via ftp from 
ftp.microsoft.com)

Q) 9.6  +What's the phone number for...

[From: zeos@zeos.com]  

This list of industry phone numbers is provided as a service to the net
community. It is not meant to be complete by any means, but if you have any
suggestions for additions, or if you find any errors which should be corrected,
please feel free to email me at support@zeos.com.  This list will be reposted
periodically with the appropriate updates.  

Thank you to all who have sent me corrections/additions. 

       Currently posted to: comp.sys.ibm.pc.hardware.misc (inside FAQ)
                          and in biz.zeos.general 

  Latest modification date: July 1, 1994  

*=Updated/corrected/added since last modification 

  (#)
    3Com ...................... BBS ................... 408-980-8204 9600bps
    3Com ...................... CardFacts ............. 408-727-7021
    3Com ...................... T/S ................... 800-876-3266 
    3rd Planet Software, Inc... BBS ................... 213-841-2260 2400bps
  (A)
    A.I.R. .................... Fax ................... 408-428-0950
    A.I.R. .................... Voice ................. 408-428-0800
    Abacus Concepts............ BBS ................... 616-698-8106 2400bps
    Abaton Technology.......... BBS ................... 415-438-4650 2400bps
    Accolade................... BBS ................... 408-296-8800 2400bps
    Acer America............... BBS ................... 800-833-8241 9600bps
    Acer Technologies Corp..... Tech Support .......... 408-922-0333
    Actix Systems ............. BBS ................... 408-970-3719 14400bps
    Actix Systems ............. Sales ................. 800-927-5557
    Actix Systems ............. Service ............... 408-986-1625 
    Adaptec.................... Automated FAX ......... 800-934-2766 
    Adaptec.................... BBS ................... 408-945-7727 14400bps
    Adaptec ................... General ............... 800-959-7274
    Adaptec ................... Tech Support .......... 408-945-2550
    Addstor.................... BBS ................... 415-324-4077 14400bps
    Advanced Digital Corp...... BBS ................... 714-894-0893 2400bps
    Advanced Logical Research.. BBS ................... 714-458-6834 14400bps
    Ahead Systems ............. General ............... 415-623-0900
    All Computer............... BBS ................... 416-960-8679 2400bps
    Allied Telesis............. BBS ................... 415-964-2994 2400bps
    Alloy Computer Products.... BBS ................... 508-460-8140 2400bps
    Alpha Software............. BBS ................... 617-229-2915 2400bps
    Altima .................... T/S ................... 800-356-9990 
    Altima..................... BBS ................... 510-356-2456 2400bps
    Altos Computer Systems .... General ............... 408-258-6787
    Altsys..................... BBS ................... 214-680-8592 2400bps
    Always Technology ......... Sales/Tech Support .... 818-597-1400
    AMD ....................... Literature ............ 800-222-9323
    AMD ....................... Main .................. 800-538-8450
    AMD ....................... Tech Support .......... 800-292-9263
    Amdek ..................... T/S ................... 800-722-6335 
    Amdek Corporation.......... BBS ................... 408-922-4400 2400bps
    American Megatrends (AMI) . BBS ................... 404-246-8782 V.32bis
    American Megatrends (AMI) . T/S ................... 404-246-8600
    American Megatrends (AMI).. BBS ................... 404-246-8780 14400bps
    American Power ............ T/S ................... 800-788-2208 
    AMIPRO (Upgrade to 3.0) ... Upgrading ............. 800-872-3387
    AMIPRO .................... Cust. Service ......... 404-399-5505
    Andataco .................. C/S ................... 800-443-9191
    Andataco .................. Fax ................... 619-453-9294
    APCUG (Association of
    Apogee Software............ BBS ................... 508-365-2359 16800bps
    Appian .................... Main .................. 408-730-5400 
    Appian .................... Tech Support .......... 800-422-7369  
    Apple Computer ............ Fax Back .............. 800-SOS-APPL
    Apple Computer ............ T/S USA Only .......... 800-SOS-APPL
    Applied Engineering........ BBS ................... 214-241-6677 2400bps
    Areal Technology Inc ...... General ............... 408-436-6800
    Artisoft .................. BBS ................... 602-884-8648
    Artisoft .................. Sales ................. 800-TINY-RAM
    Artisoft .................. T/S ................... 602-670-7000 
    Artist Graphics............ BBS ................... 612-631-7669 2400bps
    Asante Technologies ....... Voice ................. 800-622-7464
    Asante Technologies ....... Fax ................... 408-432-6018
    Asante Technologies ....... Fax Back .............. 800-741-8607
    Asante Technologies ....... BBS ................... 408-432-1416 14.4N81
    Asante Technologies ....... E-mail ................ support@asante.com
    Asante Technologies ....... FTP ................... ftp.asante.com
    Ashton-Tate ............... BBS ................... 213-324-2188
    Ask Sam Systems............ BBS ................... 904-584-8287 2400bps
    AST Research .............. BBS ................... 714-727-4723 
    AST Research .............. BBS(>9600) ............ 714-727-4132 
    AST Research .............. T/S ................... 800-727-1278 
    Asus motherboard (Aorta) .. General ............... 408-956-9077
    Asymetrix.................. BBS ................... 206-451-1173 14400bps
    AT&T ...................... Tech Support .......... 800-247-1212
    AT&T Computer Systems...... BBS ................... 908-769-6397 2400bps
    Atari ..................... General ............... 408-745-2000
    ATI Technologies .......... BBS ................... 905-764-9404 9600bps
    ATI Technologies .......... Compuserve ............ 74740,667
    ATI Technologies .......... Compuserve ............ GO ATITECH-
    ATI Technologies .......... Customer Service ...... 905-882-2626
    ATI Technologies .......... Fax ................... 905-882-2620
    ATI Technologies .......... Sales ................. 905-882-2600
    ATI Technologies .......... Tech Support .......... 905-756-0711
    ATI Technologies........... BBS ................... 416-764-9404 14400bps
    Automated Design Systems... BBS ................... 404-394-7448 2400bps
    Award (Bios) .............. BBS ................... 408-370-3139
    Award (Bios) .............. Tech Support .......... 415-968-4433
  (B)
    Beagle Bros................ BBS ................... 619-558-6151 2400bps
    Bestgift Service........... BBS ................... 813-978-3044 2400bps
    Big State Doors............ BBS ................... 512-398-7346 14400bps
    Black Box ................. Sales/Tech Support .... 412-746-5500
    Blackmond Software......... BBS ................... 505-589-0319 96H00bps
    Boca ...................... T/S ................... 407-241-8088
    Boca Research.............. BBS ................... 407-241-1601 14400bps
    Borland ................... Automated Support ..... 800-524-8420
    Borland.................... BBS ................... 408-439-9096 2400bps
    Borland ................... Compuserve ............ GO BORLAND
    Borland ................... Corporate Sales ....... 800-331-0877
    Borland ................... Fax Back .............. 800-822-4269
    Borland ................... General ............... 404-431-5250
    Borland ................... Sales ................. 800-331-0877
    Borland ................... T/S ................... 408-438-5300
    Borland ................... T/S ................... 800-252-5547
    Boston Computer Society ... BBS ................... 617-964-6939
    Bourbaki................... BBS ................... 208-342-5823 2400bps
    Box Hill Systems .......... General ............... 800-727-3863 
    Brightbill Roberts......... BBS ................... 315-472-1058 2400bps
    Brightwork Development..... BBS ................... 914-667-4759 2400bps
    Brother ................... T/S ................... 800-284-4357 
    Brown Bag Software......... BBS ................... 408-371-7654 16800bps
    Buerg Software............. BBS ................... 707-778-8944 2400bps
    BusLogic .................. BBS ................... 408-492-1984 
    BusLogic .................. Tech Support .......... 408-492-9090 
    BusLogic .................. Tech Support .......... 408-988-7338
    BusLogic .................. Tech Support FAX ...... 408-492-1542
    Buttonware................. BBS ................... 206-454-7875 14400bps
    Byte (magazine) ........... BBS ................... 617-861-9764
  (C)
    Cabletron.................. BBS ................... 603-335-3358 14400bps
    Cabletron.................. Compuserve ............ go CTRON
    Cabletron Systems ......... FTP ................... 134.141.197.25
    Cabletron Systems ......... internet .............. sales@ctron.com
    Cabletron Systems ......... internet .............. support@ctron.com
    Cabletron Systems ......... T/S & Sales ........... 603-332-9400 
    Calcomp ................... T/S ................... 800-CAL-COMP 
    Calcomp.................... BBS ................... 714-821-2359 2400bps
    Calera Recognition Systems. BBS ................... 408-773-9068 9600bps
    Campbell Services.......... BBS ................... 313-559-6434 2400bps
    Canon ..................... Main Office ........... 516-488-6700
    Canon ..................... Tech Support .......... 800-423-2366
    Canon Printer (Italy)...... BBS ................... 9-2-58010997 16800bps
    Canon Printer Division..... BBS ................... 516-488-6528 9600bps
    Cardinal (Techs) .......... Tech Support .......... 717-293-3135
    Cardinal 14.4 modem ....... Tech Support .......... 717-293-3124
    Cardinal Technologies...... BBS ................... 717-293-3074 14400bps
    Cardz...................... BBS ................... 604-734-5400 96H00bps
    CBIS, Inc.................. BBS ................... 404-446-8405 2400bps
    cc:Mail.................... BBS ................... 415-691-0401 2400bps
    CD Publishing Corp ........ FAX ................... 604-874-1431
    CD Publishing Corp ........ General ............... 604-874-1430
    CD Publishing Corp ........ General ............... 800-333-7565
    CD-ROM Inc ................ Fax ................... 303-526-7395 
    CD-ROM Inc ................ General ............... 303-526-7600
    Central Point Software .... BBS ................... 503-690-6650 14400bps
    Central Point Software .... PC Tools Tech Support . 503-690-8090
    Central Point Software .... T/S ................... 503-690-8080 
    Certus..................... BBS ................... 216-546-1508 2400bps
    Cheyenne Software.......... BBS ................... 516-484-3445 2400bps
    Chicony ................... Tech Support .......... 714-771-9067
    Chipsoft................... BBS ................... 619-453-5232 2400bps
    Chips and Technologies .... General ............... 800-323-4477
    Chwatal Development Co..... BBS ................... 318-487-0800 14400bps
    Ciprico ................... General ............... 612-559-2034
    Cirrus Logic .............. BBS ................... 510-440-9080 
    Cirrus .................... General ............... 800-272-1135
    Cirrus Logic .............. General ............... 510-623-8300
    Citizen America ........... General ............... 800-477-4683
    Citizens America Corp...... BBS ................... 310-453-7564 2400bps
    Citrix .................... Fax ................... 305-341-6880 
    Citrix .................... General ............... 305-755-0559
    Citrix .................... General ............... 800-437-7503
    Citrix Systems............. BBS ................... 305-346-9004 2400bps
    Clarion Software........... BBS ................... 305-785-9172 2400bps
    Claris Corp................ BBS ................... 408-987-7421 14400bps
    Clark Development Corp..... BBS ................... 801-261-8976 16800bps
    Clear Software............. BBS ................... 617-965-5406 2400bps
    CMS Enhancement, Inc. ..... T/S ................... 714-222-6000 
    CNET....................... BBS ................... 408-954-1787 2400bps
    Coconut Computing Inc...... BBS ................... 619-456-0815 14400bps
    Codenoll................... BBS ................... 914-965-1972 2400bps
    Colorado Memory Systems ... BBS ................... 303-635-0650 (8N1)
    Colorado Memory Systems.... BBS ................... 303-679-0650 2400bps
    Colorado Memory Systems ... Tech Support .......... 303-635-1500
    Columbia Data Products..... BBS ................... 407-862-4724 2400bps
    Commodore Business Mach.... Tech Support .......... 215-431-9100
    Communications Research.... BBS ................... 504-926-5625 2400bps
    Compaq Computer Systems.... BBS ................... 713-378-1418 14400bps
    Compaq .................... General ............... 713-370-0670
    Compaq .................... T/S ................... 800-888-5858 
    Compaq .................... Tech Support .......... 800-345-1518 
    Compati ................... Tech Support .......... 815-756-3411
    Compex .................... Voice ................. 714-630-7302
    Compex .................... Fax ................... 714-630-6521
    Compuadd .................. Tech Support .......... 800-456-3116
    CompUSA ................... General ............... 703-749-4488
    CompuServ Info. Serv. ..... General ............... 800-848-8199
    Computer Peripherals Inc .. BBS ................... 805-499-9646 14400bps
    Computer Peripherals Inc .. Tech Support .......... 805-499-5751
    Computer Support........... BBS ................... 214-404-8652 14400bps
    Computers International.... BBS ................... 213-823-3609 14400bps
    Computone Corp. ........... BBS ................... 404-343-9737 
    Computone Corp. ........... BBS ................... 404-664-1210 
    Computone Corp. ........... General ............... 404-475-2725
    Computone Corp. ........... Tech Support .......... 404-475-2725 x250
    Comtrol.................... BBS ................... 612-631-9310 2400bps
    Conner Peripherals ........ BBS ................... 408-456-4415 V.32
    Conner Peripherals ........ Fax Back .............. 408-456-4903
    Conner Peripherals ........ Tech Support .......... 408-456-3388
    Conner Peripherals ........ Tech Support .......... 800-421-1879
    Conner Peripherals ........ Tech Support .......... 800-426-6637
    Control Data Corp. (CDC) .. General ............... 612-851-4131
    Core International ........ BBS ................... 407-241-2929 2400bps
    Core International ........ Tech Support .......... 407-997-6044
    Corel ..................... General ............... 800-836-7274 
    Corel System............... BBS ................... 613-728-4752 14400bps
    Cornerstone................ BBS ................... 408-435-8943 2400bps
    Corvus System, Inc......... BBS ................... 408-972-9154 2400bps
    Covox Corpoartion.......... BBS ................... 503-342-8261 14400bps
    CPI ....................... T/S ................... 800-235-7618 
    Creative Labs.............. C/S ................... 800-998-1000
    Creative Labs.............. BBS ................... 405-742-6660 14400bps
    Creative Labs.............. ftp ................... ftp.creaf.com
    Creative Labs ............. T/S ................... 405-742-6622
    Cross Communications....... BBS ................... 303-444-9003 14400bps
    Crosstalk Communications .. BBS ................... 404-740-8428
    CTX (monitors) ............ BBS ................... 909-594-8973
    CTX (monitors) ............ Repair (East Coast) ... 800-342-5289
    CTX (monitors) ............ Repair (West Coast) ... 800-289-2189
    CTX (monitors) ............ Service Center ........ 800-888-2012
    Cumulus.................... BBS ................... 216-464-3019 2400bps
    CYRIX ..................... BBS ................... 214-994-8610 14400bps
    CYRIX ..................... E-mail ................ tech_support@cyrix.com
    CYRIX ..................... General ............... 800-FAS-MATH     
    CYRIX ..................... T/S ................... 800-327-6284 
    CYRIX ..................... T/S ................... 800-GO-CYRIX
    CYRIX ..................... Technical Support ..... 800-848-2979 x325
  (D)
    D-Link Systems, Inc........ BBS ................... 714-455-1779 14400bps
    D-Link .................... LAN adaptors/cards .... 800-361-5265
    DAC Software............... BBS ................... 214-931-6617 2400bps
    DAK Online Resource Center. BBS ................... 818-715-7153 14400bps
    Dallas  (chip)............. Tech Support .......... 510-796-6100
    Dariana Technology Group... BBS ................... 714-994-7410 2400bps
    Darwin Systems............. BBS ................... 301-251-9206 14400bps
    Data Access................ BBS ................... 305-238-0640 2400bps
    Data Shield ............... T/S ................... 312-329-1601
    Data Technology Corp ...... BBS ................... 408-942-4010 
    Data Technology Corp ...... Tech Support .......... 408-262-7700
    Datadesk/Prometheus........ BBS ................... 503-691-5199 9600bps
    DataEase Int'l............. BBS ................... 203-374-6302 2400bps
    Datapoint ................. General ............... 210-593-7000 
    Dataproducts Corp.......... BBS ................... 818-887-8167 9600bps
    Datastorm (Procomm) ....... BBS ................... 314-875-0503 14400bps
    Datastorm (Procomm) ....... Business .............. 314-443-3282
    Datastorm (Procomm) ....... Fax ................... 314-875-0595
    David Systems.............. BBS ................... 408-720-0406 2400bps
    Dayna Communications....... BBS ................... 801-535-4205 2400bps
    DCA........................ BBS ................... 404-740-8428 9600bps
    Dell Computer ............. BBS ................... 512-728-8528
    Dell Computer ............. Customer Service ...... 800-624-9897
    Dell Computer ............. Sales ................. 800-426-5150 
    Dell Computer ............. Tech Fax .............. 800-950-1329
    Dell Computer ............. Tech Support .......... 800-624-9896
    Dell Computer Corp......... BBS ................... 512-338-8528 14400bps
    Delphi..................... BBS ................... 800-365-4636 2400bps
    Delrina Technology Inc..... BBS ................... 416-441-2752 16800bps
    Delrina Technology Inc..... General ............... 416-441-3676
    DeltaComm Development...... BBS ................... 919-481-9399 16800bps
    Diamond ................... BBS 2400 baud.......... 408-730-1100
    Diamond ................... BBS 9600 baud ......... 408-524-9301
    Diamond ................... Fax ................... 408-773-8000
    Diamond ................... Tech Support .......... 408-736-2000
    Diconix ................... T/S ................... 513-259-3100 
    Digiboard Inc. ............ BBS ................... 612-943-0812 2400bps
    Digiboard Inc. ............ Tech Support .......... 612-943-9020 
    Digicom Systems, Inc ...... BBS ................... 408-262-5629
    Digicom Systems, Inc ...... Voice ................. 408-262-1277
    Digital Communications..... BBS ................... 513-433-5080 2400bps
    Digital Equip. Corp.(DEC) . General ............... 508-493-5111
    DEC ....................... ordering by modem ..... 800-234-1998
    DEC ....................... ordering by fax ....... 800 234-2298
    DEC ....................... ordering by fax ....... 800-524-5694
    DEC ....................... ordering by phone ..... 800 PC BY DEC
    DEC ....................... Product info .......... 800-DIGITAL
    DEC ....................... Tech Support .......... 800-354-9000
    Digital Research .......... Tech Support .......... 408-646-6464
    Digital Research........... BBS ................... 408-649-3443 2400bps
    Digital Vision............. BBS ................... 617-329-8387 14400bps
    Digitrend Systems Corp. ... General ............... 818-772-0190
    Dilog ..................... General ............... 408-241-3192
    Disk Technician Corporation BBS ................... 619-272-9240 2400bps
    DNA Networks, Inc.......... BBS ................... 215-296-9558 2400bps
    Dove Computer.............. BBS ................... 919-343-5616 14400bps
    DPT (Dist Process Tech) ... BBS ................... 407-831-6432
    DPT (Dist Process Tech) ... General ............... 407-260-3566
    DPT (Dist Process Tech) ... Tech Support .......... 407-830-5522
    DSI (Digicom Systems) ..... BBS ................... 408-262-5629
    DSI (Digicom Systems) ..... Sales ................. 800-833-8900
    DSI (Digicom Systems) ..... Tech Support .......... 408-262-1277
    DTC ....................... BBS ................... 408-942-4010
    DTC ....................... Fax ................... 408-942-4052
    DTC ....................... Fax Back .............. 408-942-4005
    DTC ....................... General ............... 408-942-4000
    DTK........................ Main .................. 818-810-8880
    DTK........................ Tech Support (IL) ..... 800-804-8048
    DTK........................ Tech Support (NJ) ..... 908-562-8800
    DTK........................ Tech Support (GA) ..... 800-746-4386
    DTK........................ Tech Support (FL) ..... 305-597-8888
    Dudley Software............ BBS ................... 615-966-3574 2400bps
    Durant Technologies ....... T/S ................... 800-451-4813 
    Dynamic Microprocessor..... BBS ................... 516-462-6638 2400bps
    Dysan Corp................. Tech Support .......... 408-988-3472
  (E)
    EagleSoft.................. BBS ................... 812-479-1310 16800bps
    Eastman Kodak ............. T/S ................... 800-255-3434
    Elite Business App's....... BBS ................... 410-987-2335 2400bps
    Emac/Everex................ BBS ................... 510-226-9694 2400bps
    Emerald Systems ........... T/S ................... 800-366-4349
    Emerald Systems............ BBS ................... 619-673-4617 2400bps
    Enable Software............ BBS ................... 518-877-6316 2400bps
    Envisions ................. BBS ................... 415-259-8145
    Epson ..................... T/S ................... 800-922-8911
    Epson ..................... Tech Support .......... 213-539-9955
    Epson America, Inc......... BBS ................... 310-782-4531 9600bps
    Equinox Systems, Inc....... BBS ................... 305-378-1696 2400bps
    eSoft Inc.................. BBS ................... 303-699-8222 16800bps
    ETS Incorporated........... BBS ................... 801-265-0919 14400bps
    Everex Systems ............ BBS ................... 510-438-4650
    Everex Systems ............ Tech Support .......... 510-498-1115
    Exabyte ................... Sales ................. 800-445-7736
    Exabyte ................... T/S ................... 303-447-4323
    Exabyte ................... BBS ................... 303-447-7100
    Exabyte Direct Srvce Admn . Fax ................... 303-447-7199
    Excalibur.................. BBS ................... 408-244-0813 14400bps
    Exis....................... BBS ................... 416-439-8293 14400bps
    EZX Publishing............. BBS ................... 713-280-8180 14400bps
  (F)
    Family Scrapbook........... BBS ................... 904-249-9515 16800bps
    Fifth Generation Systems .. BBS ................... 504-295-3344
    Fifth Generation Systems .. T/S ................... 800-766-7283 
    Fifth Generation Systems .. T/S: Mace, Fastback ... 800-873-4384
    Fifth Generation Systems... BBS ................... 504-295-3344 2400bps
    Flashllink ................ BBS ................... 717-293-3074 
    FlashTek .................. BBS ................... 208-883-3859
    FlashTek .................. Email ................. flashtek@proto.com
    FlashTek .................. England ............... 44-476-74108
    FlashTek .................. General ............... 208-882-7275
    FlashTek .................. Orders ................ 800-397-7310
    Folio...................... BBS ................... 801-375-9907 2400bps
    Foresight Resources........ BBS ................... 816-891-8465 2400bps
    Frederick Engineering, Inc. BBS ................... 301-290-6944 2400bps
    FreeLance ................. Cust Support .......... 800-223-1662
    Fresh Technology........... BBS ................... 602-497-4235 2400bps
    Fujitsu America ........... T/S ................... 408-432-1300 
    Fujitsu America, Inc. ..... Tech Support .......... 800-826-6112
    Fujitsu America, Inc....... BBS ................... 408-944-9899 9600bps
    Future Domain ............. Tech Support .......... 714-253-0400
    Future Domain ............. Update Center ......... 800-879-7599 
    Future Domain.............. BBS ................... 714-253-0432 2400bps
    FutureSoft Engineering..... BBS ................... 713-588-6870 2400bps
  (G)
    Galacticomm................ BBS ................... 305-583-7808 14400bps
    GAP Development Company.... BBS ................... 714-493-3819 14400bps
    Gateway ................... General ............... 800-846-2000 
    Gateway ................... T/S ................... 714-553-1555 
    Gateway ................... Tech Support .......... 800-846-2301 
    Gateway BBS................ BBS ................... 605-232-2109 14400bps
    Gateway Communications..... BBS ................... 714-863-7097 2400bps
    Gazelle Systems ........... T/S: Optune ........... 800-233-0383
    Gazelle Systems............ BBS ................... 801-375-2548 2400bps
    GEcho...................... BBS ................... 316-263-5313 16800bps
    General DataComm Ind....... BBS ................... 203-598-0593 14400bps
    GEnie Information Services. BBS ................... 800-638-8369 2400bps
    Genoa ..................... BBS ................... 408-943-1231 2400bps
    Genoa ..................... Tech Support .......... 408-432-9090
    Genovation ................ Fax ................... 714-833-0322
    Genovation ................ General ............... 714-833-3355
    Gensoft Development........ BBS ................... 206-562-9407 2400bps
    GeoClock................... BBS ................... 703-241-7980 14400bps
    GeoWorks .................. T/S ................... 415-644-3456 
    Gibson Research ........... BBS ................... 714-362-8848 2400bps
    Gibson Research ........... Sales-T/S: Spinwrite .. 714-362-8800 
    GigaTrend, Inc............. BBS ................... 619-566-0361 2400bps
    Global Village Comm........ BBS ................... 415-390-8397 14400bps
    Goldstar .................. T/S ................... 800-777-1192
    Goldstar .................. Tech Support .......... 408-432-1331
    Goldstar Technologies...... BBS ................... 408-432-0236 14400bps
    Graphic Workshop........... BBS ................... 416-729-4609 14400bps
    Gravis .................... BBS ................... 604-431-5927 
    Gravis .................... Tech Support .......... 604-431-1807 
    Great American Software.... BBS ................... 603-889-7292 2400bps
    Gupta Technologies, Inc.... BBS ................... 415-321-0549 2400bps
    GVC Technologies........... BBS ................... 201-579-2380 14400bps
  (H)
    HardDrives Intl............ Sales? ................ 800-998-8093 
    Hayes ..................... T/S ................... 404-441-1617
    Hayes Microcomputer........ BBS ................... 404-446-6336 14400bps
    Hayes Microcomputer........ BBS ................... 800-874-2937 14400bps
    Hayes On-line ............. BBS (product info) .... 800-874-2937 
    Hazard Soft................ BBS ................... 405-243-3200 16800bps
    HDC Computer............... BBS ................... 206-869-2418 2400bps
    Headland .................. General ............... 510-656-0503
    Headland Technology........ BBS ................... 415-656-0503 2400bps
    Headstart ................. T/S ................... 800-722-6224
    Hercules Computer Tech. ... BBS ................... 510-623-7034 
    Hercules Computer Tech. ... Tech Support .......... 510-623-6030 
    Hercules Computer.......... BBS ................... 510-540-0621 2400bps
    Hewlett-Packard Co. ....... Customer Information .. 800-752-0900
    Hewlett-Packard Co. ....... Fax Back .............. 800-331-1917
    Hewlett-Packard Co. ....... BBS ................... 408-553-3500
    Hewlett-Packard Co. ....... Tech Support .......... 800-858-8867
    Hitachi ................... T/S ................... 224-785-9770
    Houston Instruments ....... T/S ................... 800-444-3425 
    Hyundai Electronics ....... Tech Support .......... 800-234-3553
  (I)
    i-link .................... email (Germany) ....... info@ilink.de
    i-link .................... General (Germany) ..... +4930-216-20-48
    IBM PC Users Group ........ BBS ................... 404-988-2790
    IBM........................ Automated Fax ......... 800-426-3395
    IBM........................ BBS ................... 919-517-0001 14400bps
    IBM........................ FTP ................... software.watson.ibm.com
    IBM ....................... General ............... 800-426-3333
    IBM ....................... PS/2 HelpCenter ....... 800-772-2227
    IMC Networks............... BBS ................... 714-724-0930 2400bps
    IMSI Software.............. BBS ................... 415-454-2893 2400bps
    Indelible Blue ............ Fax ................... 919-878-7479
    Indelible Blue ............ General ............... 800-776-8284
    Indelible Blue ............ General ............... 919-878-9700
    Infinity Computer Services. BBS ................... 215-965-8028 2400bps
    Infochip Systems........... BBS ................... 408-727-2496 2400bps
    Informix................... BBS ................... 913-492-2089 2400bps
    InfoShare.................. BBS ................... 703-803-8000 96H00bps
    Innovative Data Concepts... BBS ................... 215-357-4183 2400bps
    Inset Corporation.......... BBS ................... 203-740-0063 14400bps
    Insignia Solutions......... BBS ................... 415-694-7694 2400bps
    Integrated Inf Tech ....... BBS ................... 408-727-0952
    Integrated Inf Tech ....... Mathco T/S ............ 800-448-5033
    Integrated Inf Tech ....... XtraDrive T/S ......... 408-727-1676
    Intel...................... BBS ................... 503-645-6275 14400bps
    Intel ..................... Cust. Support/FaxBack.. 800-538-3373
    Intel ..................... FaxBack ............... 800-525-3019
    Intel ..................... FaxBack ............... 503-629-7576
    Intel ..................... Fax ................... 503-629-7580
    Intel ..................... Fax ................... 800-458-6231
    Intel ..................... Sales ................. 800-538-3373
    Intel ..................... Sales ................. 503-629-7354
    Intel Application Support.. BBS ................... 916-356-3600 14400bps
    Intelligent Graphics Corp.. BBS ................... 408-441-0386 2400bps
    Intracorp.................. BBS ................... 305-378-8793 2400bps
    Intuit .................... ....................... 800-624-8742 
    Iomega .................... T/S ................... 800-456-5522
    Iomega..................... BBS ................... 801-778-4400 2400bps
    Irma DCA .................. T/S ................... 404-740-0300
    Irwin ..................... T/S ................... 800-421-1879
    Irwin Magnetics............ BBS ................... 313-930-9380 9600bps
  (J)
    JDR Microdevices........... BBS ................... 408-559-0253 2400bps
    Jetfax..................... BBS ................... 415-324-1259 2400bps
    Jetform.................... BBS ................... 613-563-2894 2400bps
  (K)
    Kalok (HDD) ............... BBS ................... 408-738-4258
    Kalok (HDD) ............... FAX ................... 408-747-1319
    Kalok (HDD) ............... Voice ................. 408-747-1315
    Kaypro .................... Tech Support .......... 619-481-3900
    Kensington Microware ...... T/S ................... 800-535-4242 
    Kent Marsh................. BBS ................... 713-522-8921 2400bps
    Keytronics ................ Tech Support .......... 800-262-6006
    Kodiak Technology ......... BBS ................... 408-452-0677 2400bps
    Kodiak Technology ......... Tech Support .......... 800-777-7704
    Kurta ..................... T/S ................... 800-645-8782 
    Kurta Corp................. BBS ................... 602-243-9440 2400bps
  (L)
    LAN (magazine) ............ BBS ................... 415-267-7640
    LAN Master................. BBS ................... 817-771-0233 16800bps
    LAN Systems................ BBS ................... 801-373-6980 2400bps
    LAN Works.................. BBS ................... 416-238-0253 2400bps
    Laser Go................... BBS ................... 619-450-9370 2400bps
    Lattice.................... BBS ................... 708-916-1200 2400bps
    Leading Edge .............. Customer Service ...... 800-874-3340
    Leading Edge .............. Tech Support .......... 800-245-9870
    Leading Edge............... BBS ................... 508-836-3971 14400bps
    Lexmark ................... BBS ................... 606-232-5238
    Lexmark ................... Fax ................... 606-232-2380
    Lexmark ................... Voice ................. 606-232-3000
    Lexmark ................... BBS ................... 800-453-9223 2400bps
    Liant Software ............ BBS ................... 508-626-0681 9600bps
    Liant Software ............ Tech Support .......... 508-875-2294
    Lightning Communications... BBS ................... 714-457-9429 9600bps
    Logical Connection......... BBS ................... 504-295-3344 2400bps
    Logitech................... BBS ................... 510-795-0408 14400bps
    Logitech .................. Tech Support .......... 510-795-8100
    Lotus ..................... Cust. Support ......... 800-223-1662
    Lotus Development ......... General ............... 617-577-8500
    Lotus Tech Support ........ Support ............... 404-399-5505
    Lotus...................... BBS ................... 404-395-7707 2400bps
    Lotus...................... BBS ................... 617-693-7000 2400bps
    Lucas Games ............... BBS ................... 415-257-3070
  (M)
    Mace, Paul Software ....... BBS ................... 714-240-7459
    Mace, Paul Software ....... Tech Support .......... 800-523-0258
    Mace, Paul Software........ BBS ................... 503-482-7435 2400bps
    Macronix .................. Tech Support .......... 800-468-4629
    Macronix ...California .... Tech Support ...only... 408-453-8088
    Madge Networks............. BBS ................... 408-441-1340 2400bps
    Magee Enterprises, Inc..... BBS ................... 404-446-6650 16800bps
    Magitronic Technology...... BBS ................... 516-454-8262 14400bps
    Magnavox .................. T/S ................... 800-722-6224
    Magnavox................... BBS ................... 310-532-6436 14400bps
    Main Lan................... BBS ................... 407-331-7433 2400bps
    Mannesman Tally............ BBS ................... 206-251-5513 2400bps
    Mansfield Software Group... BBS ................... 203-429-3784 14400bps
    Manx Software Systems...... BBS ................... 201-542-2793 2400bps
    Matrix Technology.......... BBS ................... 617-569-3787 2400bps
    Maxi Host Support.......... BBS ................... 209-836-2402 2400bps
    Maxis Software............. BBS ................... 510-254-3869 14400bps
    Maxtor/Miniscribe ......... BBS ................... 303-678-2222 14400bps
    Maxtor/Miniscribe ......... E-mail ............... Gary_Anderson@Maxtor.com
    Maxtor/Miniscribe ......... Fax ................... 303-678-2618 
    Maxtor/Miniscribe ......... General ............... 303-651-6000
    Maxtor/Miniscribe ......... Tech Support .......... 800-356-5333
    Maxtor/Miniscribe ......... T/S ................... 800-2-MAXTOR 
    Maynard Electronics........ BBS ................... 407-263-3502 2400bps
    Maynard Electronics........ General................ 800-227-6296 
    McAfee Assoc............... BBS ................... 408-988-4004 16800bps
    McAfee Assoc............... Fax ....................408-970-9727
    McAfee Assoc............... General ............... 408-988-3832
    McAfee Assoc............... Internet .............. mcafee.com
    McAfee Assoc............... Internet ip............ 192.187.128.1
    Media Vision............... BBS ................... 510-770-0968 14400bps
    MediaVision ............... BBS ................... 510-770-0527
    MediaVision ............... General ............... 800-684-6699
    MediaVision ............... Tech Support .......... 800-638-2807
    Megahertz Corp. ........... Sales ................. 800-LAPTOPS
    Megahertz Corp. ........... T/S ................... 800-527-8677
    Metheus ................... T/S ................... 503-690-1550 
    Micro Display Systems...... BBS ................... 612-438-3513 2400bps
    Micro Solutions............ BBS ................... 815-756-9100 14400bps
    Microbotics ............... Tech Support .......... 214-437-5330
    Microcom................... BBS ................... 617-762-5134 2400bps
    Microdyne.................. BBS ................... 703-739-0432 2400bps
    Microid Research .......... FAX ................... 408-727-6996
    Microid Research .......... Voice ................. 408-727-6991
    Micron Technology.......... BBS ................... 208-368-4530 2400bps
    Micronet .................. General ............... 714-837-6033
    Micronics ................. General ............... 510-651-2300
    Micronics.................. BBS ................... 510-651-6837 14400bps
    Micropolis Corp ........... BBS ................... 818-709-3310 2400bps
    Micropolis Corp ........... Tech Support .......... 818-709-3325
    MicroProse................. BBS ................... 301-785-1841 2400bps
    Microrim................... BBS ................... 206-649-9836 2400bps
    Microscience Int .......... Tech Support .......... 408-433-9898
    
    Microsoft ................. BBS ................... 206-646-9145
    Microsoft ................. BBS 9600 .............. 206-936-6735
    Microsoft ................. BBS Canada ............ 905-507-3022
    Microsoft ................. FTP ................... ftp.microsoft.com
    Microsoft ................. FTP ................... gowinnt.microsoft.com
    Microsoft ................. Cust. Support ......... 800-426-9400
    Microsoft Access .................................. 206-635-7050
    Microsoft Basic PDS ............................... 206-635-7053
    Microsoft C Compiler .............................. 206-635-7007
    Microsoft COBOL ................................... 206-637-7096
    Microsoft Customer Sales & Service ................ 800-426-9400
    Microsoft Corporate Switchboard ................... 206-882-8080
    Microsoft DOS 5 ................................... 206-646-5104
    Microsoft DOS 5 recordings ........................ 206-646-5103
    Microsoft Excel for Macintosh ..................... 206-635-7080
    Microsoft Excel for Windows & Excel for OS/2 ...... 206-635-7070
    Microsoft FORTRAN Compiler ........................ 206-635-7015
    Microsoft LAN Manager for UNIX .................... 206-635-7021
    Microsoft Macro Assembler ......................... 206-646-5109
    Microsoft Mail for Windows & Mail for Macintosh ... 206-637-9307
    Microsoft Money for Windows ....................... 206-635-7131
    Microsoft Mouse, BallPoint, & Hardware ............ 206-637-7096
    Microsoft Pascal .................................. 206-637-7096
    Microsoft PowerPoint for Windows .................. 206-635-7145
    Microsoft PowerPoint for Macintosh ................ 206-635-7145
    Microsoft Profiler ................................ 206-635-7015
    Microsoft Project for Windows and Macintosh ....... 206-635-7155
    Microsoft Project for MS-DOS ...................... 206-635-7155
    Microsoft Publisher for Windows ................... 206-635-7140
    Microsoft Quick Assembler ......................... 206-635-7010
    Microsoft QuickC Compiler ......................... 206-635-7010
    Microsoft Test Tools for Windows .................. 206-635-7052
    Microsoft Visual Basic Startup .................... 206-646-5105
    Microsoft Windows Applications for OS/2 ver. 2.0 .. 206-635-7247
    Microsoft Windows Environment ..................... 206-637-7098
    Microsoft Windows Applications .................... 206-637-7099
    Microsoft Word for Macintosh ...................... 206-635-7200
    Microsoft Word for MS-DOS ......................... 206-635-7210
    Microsoft Word for OS/2 ........................... 206-454-2030
    Microsoft Word for Windows ........................ 206-462-9673
    Microsoft Works for Macintosh ..................... 206-635-7160
    Microsoft Works for MS-DOS ........................ 206-635-7150
    Microsoft Works for Windows ....................... 206-635-7130

    ***** ALL Microsoft OTHER PRODUCTS ................ 206-454-2030

        MICROSOFT STARTUP AND INSTALLATION SUPPORT

    Microsoft LAN Manager Startup (first 30 days only). 206-635-7020
    Microsoft MS-DOS 5.0 (first 90 days only) ......... 206-646-5104
    Microsoft QuickBASIC Startup ...................... 206-646-5101
    Microsoft SQL Server Startup (first 30 days only).. 206-637-7095
    Microsoft Visual Basic Startup .................... 206-646-5105
    Microsoft Windows Entertainment Pack .............. 206-637-9308
    Microsoft Windows Software Development Kit (SDK)... 206-635-3329

        FAST TIPS SERVICES
    Microsoft Fast Tips General ....................... 800-936-4100
    Microsoft Excel for Macintosh ..................... 206-635-7081
    Microsoft Excel for Windows ....................... 206-635-7071
    Microsoft MS-DOS 5.0 .............................. 206-646-5103
    Microsoft Project for Windows ..................... 206-635-7156
    Microsoft Visual Basic ............................ 206-646-5107
    Microsoft Windows ................................. 206-635-7245
    Microsoft Word for Macintosh ...................... 206-635-7201
    Microsoft Word for MS-DOS ......................... 206-635-7211
    Microsoft Word for Windows ........................ 206-635-7231

        INCREMENTAL FEE-BASED SUPPORT

    Microsoft OnCall for Basic $2/min.................. 900-896-9999
    Microsoft OnCall for Basic $20/call ............... 206-646-5106
    Microsoft OnCall for MS-DOS $2/min................. 900-896-9000
    Microsoft OnCall for MS-DOS $20/call .............. 206-646-5108
    Microsoft OnCall for Visual Basic $2/min........... 900-896-9876
    Microsoft OnCall for Visual Basic $20/call ........ 206-646-5106
    Microsoft Network Support $175/call ............... 206-635-7022

    Microsystems Software...... BBS ................... 508-875-8009 2400bps
    Microtech.................. BBS ................... 203-469-6430 2400bps
    MicroTek................... BBS ................... 310-538-4032 14400bps
    Microtest.................. BBS ................... 602-996-4009 2400bps
    Mitsubishi Inc. ........... T/S ................... 800-344-6352
    Mitsubishi Inc............. Tech Support .......... 213-515-3993
    Mitsubishi................. BBS ................... 714-636-6216 2400bps
    Mitsumi ..................  Sales ................. 516-752-7730 
    Mitsumi ..................  Tech Support .......... 408-970-9699 
    Mitsumi ..................  Tech Support .......... 408-970-9730 
    Motorola................... BBS ................... 800-843-3451
    Motorola................... BBS ................... 512-891-3733
    Motorola................... BBS ................... 512-891-3733
    Mountain Computer, Inc .... BBS ................... 408-438-2665
    Mountain Computer, Inc .... General ............... 800-458-0300
    Mountain Computer, Inc .... Tech Support .......... 408-438-7897
    Mouse Systems (MSC)........ BBS ................... 510-683-0617 14400bps
    Mouse Systems ............. Tech Support .......... 510-656-1117
    Multi-Tech Systems......... BBS ................... 612-785-9875 14400bps
    Mustang Software........... BBS ................... 805-395-0650 16800bps
    Mustang Software .......... MSI HQ BBS ............ 805-873-2400
    Mustang Software .......... T/S ................... 805-873-2550
    Mustang Software .......... OFFICE ................ 805-873-2500
    Mustang Software .......... FAX ................... 805-873-2599
    Mustang Software .......... SALES ................. 800-999-9619
    Mutant Group............... BBS ................... 405-372-6621 16800bps
    Mylex ..................... ....................... 800-776-9539 
    Mylex ..................... BBS ................... 510-793-3491
    Mylex ..................... Technical Support ..... 510-796-6100
  (N)
    National Design ........... ....................... 800-253-8831
    National Semiconductor..... BBS ................... 408-245-0671 2400bps
    NCR ....................... BBS ................... 719-596-1649
    NCR ....................... Video Chip Support .... 800-543-9935
    NEC ....................... T/S ................... 708-860-0335 
    NEC ....................... Tech Support ..BBS..... 508-635-4706
    NEC ....................... Tech Support ..fax..... 708-860-5475
    NEC ....................... Tech Support ..faxback. 800-366-0476
    NEC ....................... Tech Support ..General. 800-388-8888
    Network Products Corp...... BBS ................... 818-441-6933 14400bps
    NetWorth................... BBS ................... 214-869-2959 2400bps
    New Media Corp ............ General ............... 800-227-3748
    New Media Graphics......... BBS ................... 508-663-7612 14400bps
    NeXT Answers .............. automated email ....... nextanswers@next.com
    NeXT Answers .............. Fax Back .............. 415-780-3990
    NeXT ....... .............. T/S General ........... 800-848-NEXT
    Night Owl BBS.............. BBS ................... 716-881-5688 16800bps
    NISCA...................... BBS ................... 214-446-0646 2400bps
    Norton .................... Tech Support .......... 213-319-2020
    Norton-Lambert............. BBS ................... 805-683-2249 14400bps
    Norton/Symantec ........... BBS ................... 408-973-9598 2400bps
    NovaStor .................. Sales ................. 818-707-9900
    NovaStor .................. Fax ................... 818-707-9902
    Novell .................... BBS ................... 801-429-3308
    Novell .................... Tech Support .......... 800-526-5463
    Novell Desktop Systems..... BBS ................... 408-649-3443 2400bps
    Novell..................... BBS ................... 801-429-3030 14400bps
    Nuiq Software Inc.......... BBS ................... 914-833-1479 14400bps
    Number Nine................ BBS ................... 617-497-6463 96H00bps
  (O)
    OCR Systems................ BBS ................... 215-938-7245 2400bps
    Okidata ................... T/S ................... 800-634-0089 
    Okidata ................... Tech Support .......... 609-235-2600
    Okidata.................... BBS ................... 800-283-5474 9600bps
    Olivetti Office USA ....... General ............... 201-526-8200
    Omen Technology............ BBS ................... 503-621-3746 9600bps
    Ontrack Computer Systems .. BBS ................... 612-937-0860
    Ontrack Computer Systems .. Data Recovery ......... 800-872-2599
    Ontrack Computer Systems .. Sales Dos utils ....... 800-752-1333
    Ontrack Computer Systems .. Sales: Disk Manager ... 800-752-1333
    Ontrack Computer Systems .. Tech Support .......... 612-937-2121
    Open Network............... BBS ................... 718-638-2239 2400bps
    Orange Micro .............. T/S ................... 714-779-2772
    Orchid Technology ......... BBS ................... 510-683-0327 
    Orchid Technology ......... General ............... 510-683-0300
    Orchid Technology ......... Sales ................. 800-767-2443
    Orchid Technology ......... Tech Support .......... 510-683-0323
    Origin..................... BBS ................... 512-328-8402 2400bps
  (P)
    Pacific Data Product ...... T/S ................... 619-597-3444
    Pacific Data Products...... BBS ................... 619-452-6329 2400bps
    Packard Bell .............. BBS - Canada .......... 416-542-7359
    Packard Bell .............. BBS USA ............... 818-313-8601
    Packard Bell .............. Tech Support .......... 800-733-4411
    Packard Bell............... BBS ................... 818-773-7207 2400bps
    Palindrome................. BBS ................... 708-505-3336 2400bps
    Panasonic ................. T/S ................... 800-222-0584 
    Panasonic Communica'n Sys.. BBS ................... 201-863-7845
    Panasonic Printers ........ Cust Support .......... 708-468-5440
    Panasonic.................. BBS ................... 201-863-7847 2400bps
    Paperback Corporation...... BBS ................... 415-644-0782 16800bps
    Paradise .................. Tech Support .......... 800-832-4778
    Paradise Systems........... BBS ................... 714-753-1234 14400bps
    Patton & Patton Software... BBS ................... 408-778-9697 2400bps
    PC Power and Cooling ...... ....................... 619-931-5700
    PC Power and Cooling ...... ....................... 800-722-6555
    PC User Groups) ........... BBS ................... 408-439-9367
    PCubid (CPU fans) ......... General ............... 916-338-1338
    Pentax Technologies........ BBS ................... 303-460-1637 16800bps
    Perstore .................. BBS ................... 602-894-4605
    Perstore .................. Tech Support .......... 602-894-4601
    Phoenix (Bios) ............ BBS ................... 405-321-2400 14400bps
    Phoenix (Bios) ............ Tech Support .......... 617-551-4000
    Pinnacle Publishing........ BBS ................... 206-251-6217 2400bps
    Pinpoint Publishing........ BBS ................... 707-523-0468 2400bps
    PKWare..................... BBS ................... 414-354-8670 16800bps
    PKWare..................... Voice ................. 414-354-8699
    PLI........................ BBS ................... 510-651-5948 2400bps
    Plus Development .......... BBS ................... 408-434-1664
    Plus Development .......... Tech Support .......... 900-740-4433
    Plus Development .......... Tech Support ...Calif.. 800-826-8022
    Practical Peripherals ..... BBS ................... 805-496-4445 14400bps
    Practical Peripherals ..... General ............... 800-442-4774
    Practical Peripherals ..... T/S ................... 805-496-7707 
    Priam Systems ............. Tech Support .......... 408-954-8680
    Priam Systems.............. BBS ................... 408-434-1646 2400bps
    Prime Solutions ........... Tech Support Disk Tech. 800-847-5000
    Princeton Graphic Systems.. BBS ................... 404-664-1210 2400bps
    Princeton Graphics ........ T/S ................... 404-664-1010 
    ProComm Support ........... BBS ................... 314-474-8477
    Programmer's Workshop ..... General ............... 216-494-5260
    Programmer's Workshop ..... General ............... 216-494-8715
    Programmer's Workshop ..... General ............... 800-336-1166
    Prometheus Products........ BBS ................... 503-691-5199 14400bps
    Promise Technology ........ General ............... 408-452-0948
    Promise's Technology ...... Tech Support .......... 408-452-1180
    Promise's Technology ...... BBS ................... 408-452-1267
    Proteon ................... T/S ................... 508-898-3100
    Proteon.................... BBS ................... 508-366-7827 2400bps
    Public Brand Software...... BBS ................... 317-856-2087 14400bps
    Pure Data ................. T/S ................... 800-661-8210 
    Pure Data.................. BBS ................... 214-242-3225 14400bps
  (Q)
    Q+E Software .............. BBS ................... 919-851-1381
    Q+E Software .............. Sales ................. 800-876-3101
    Q+E Software .............. Technical Support ..... 919-851-1152
    QIC Standards Inc ......... Fax ................... 805-962-1541
    QIC Standards Inc ......... General ............... 805-963-3853
    Qmail...................... BBS ................... 901-382-5583 16800bps
    QMS ....................... BBS ................... 205-633-3632
    QMS ....................... FAX ................... 205-633-3145
    QMS ....................... General ............... 205-633-4300
    QNX ....................... T/S ................... 613-591-0941
    QNX ....................... Fax ................... 613-591-3579
    Quadram.................... BBS ................... 404-564-5678 2400bps
    Qualitas................... BBS ................... 301-907-8030 14400bps
    Qualitas .................. FaxFacts .............. 301-718-6066
    Qualitas .................. General ............... 301-907-6700
    Qualitas .................. Tech Support .......... 301-907-7400
    Qualitas .................. T/S FAX ............... 301-718-6061
    Qualitas .................. Toll Free ............. 800-676-6386
    Quantum.................... BBS ................... 408-894-3214 2400bps
    Quantum ................... T/S (end user) ........ 800-826-8022
    Quantum ................... T/S ................... 408-894-4000
    Quantum ................... T/S ................... 408-944-0410
    Quarterdeck ............... BBS ................... 310-314-3227 V.32bis
    Quarterdeck ............... BBS ................... 310-396-3904 14400bps
    Quarterdeck ............... Customer Service ...... 800-354-3222
    Quarterdeck ............... Fax ................... 310-314-3217
    Quarterdeck ............... Sales ................. 310-392-9851
    Quarterdeck ............... Tech Support - Fax .... 310-399-3802
    Quarterdeck ............... Tech Support - UK ..... +4471 973-0663
    Quarterdeck ............... Tech Support .......... 310-392-9701
    Quarterdeck ............... Tech Support DeskView.. 310-392-9851
    Quarterdeck ............... Tech Support Manifest.. 310-392-9851
    Quercus Systems............ BBS ................... 408-867-7488 14400bps
    Quess Micro................ BBS ................... 719-597-8670 14400bps
    Quick Link II SW .......... General ..14.4 Modem .. 714-362-5800
    QuickBBS................... BBS ................... 407-896-0494 16800bps
  (R)
    Racal Interlan/Rabbit Soft. BBS ................... 508-264-4345 2400bps
    Race....................... BBS ................... 305-271-2146 2400bps
    Rams' Island Software...... BBS ................... 303-841-6269 16800bps
    Rancho Technology ......... Tech Support .......... 714-987-3966
    RC Electronics ............ General ............... 714-375-3791 
    RelayNet National.......... BBS ................... 301-229-5623 16800bps
    Remote Control Int......... BBS ................... 619-431-4030 2400bps
    Revelation Technologies.... BBS ................... 206-641-8110 2400bps
    Ricoh Corp ................ General ............... 201-882-2000
    Rix Softworks.............. BBS ................... 714-476-0728 2400bps
    Rybs Electronics........... BBS ................... 303-443-7437 2400bps
  (S)
    S3 ........................ General ............... 408-986-8144 
    S3 ........................ BBS ................... 408-970-3719 
    Saber Software............. BBS ................... 214-361-1883 14400bps
    Salt Air BBS............... BBS ................... 801-261-8976 16800bps
    Samsung Info Systems....... BBS ................... 201-691-6238 2400bps
    Samsung Info. Syst......... BBS ................... 408-434-5684
    Samsung Info. Syst......... Tech Support .......... 800-446-0262
    Santa Cruz Operation (SCO). Tech Support .......... 800-347-4381
    Santronics Software........ BBS ................... 305-248-7815 16800bps
    Sanyo Storage Products .... General ............... 714-724-1505
    SEAboard................... BBS ................... 201-473-1991 9600bps
    SeaFax..................... Automated Fax Back Serv 408-438-2620
    Seagate Technology ........ BBS ... French ........ 33-1-40-67-1034 2400bps
    Seagate Technology ........ BBS ... Germany ....... 49-89-140-9331
    Seagate Technology ........ BBS ... Singapore ..... 65-227-2217
    Seagate Technology ........ BBS ... UK ............ 44-628-478011
    Seagate Technology ........ BBS ... USA ........... 408-438-8771 14400bps
    Seagate Technology ........ Customer Service ...... 800-468-3472
    Seagate Technology ........ General ............... 408-438-6550
    Seagate Technology ........ Sales ................. 408-438-8111
    Seagate Technology ........ Tech Support .......... 408-438-8222
    Searchlight Software....... BBS ................... 516-689-2566 9600bps
    SemWare.................... BBS ................... 404-641-8968 9600bps
    Sharp ..................... T/S ................... 708-759-8555
    Sharp...................... BBS ................... 404-962-1788 16800bps
    Shiva Corporation.......... BBS ................... 617-621-0190 2400bps
    Shugart ................... Tech Support .......... 714-770-1100
    Sierra Online.............. BBS ................... 209-683-4463 14400bps
    Sigma Design............... BBS ................... 510-770-0111 2400bps
    Silicon Valley Computers .. BBS ................... 415-967-8081
    Silicon Valley Computers .. General ............... 415-967-1100
    Sitka Corporation.......... BBS ................... 415-769-8774 2400bps
    Sitka...................... BBS ................... 510-769-8774 2400bps
    SMC ....................... BBS ................... 714-707-2481 V.32
   *SMC ....................... BBS (East Coast) ...... 516-434-3162 V.32
    SMC ....................... T/S ................... 800-992-4762
    SMS Technology............. BBS ................... 510-964-5700 9600bps
    Sofnet..................... BBS ................... 404-984-9926 14400bps
    Sofnet..................... Voice ................. 404-984-8088
    Sofnet..................... Fax ................... 404-984-9956
    Sofnet..................... Sales ................. 800-FAXWORKS
    SoftArc Inc................ BBS ................... 416-609-2250 14400bps
    Softklone.................. BBS ................... 904-878-9884 14400bps
    Softlogic Solutions ....... Tech S Disk Optimize .. 800-272-9900
    Softlogic Solutions........ BBS ................... 603-644-5556 2400bps
    Softronics ................ Fax ................... 719-548-1878
    Softronics ................ T/S ................... 719-593-9550
    Softronics................. BBS ................... 719-593-9295 2400bps
    Software Products Intl..... BBS ................... 619-450-2179 2400bps
    Software Security.......... BBS ................... 203-329-7263 2400bps
    Software Venture........... BBS ................... 510-849-1912 2400bps
    Solutions Systems.......... BBS ................... 617-237-8530 2400bps
    Sony ...................... Customer Relations .... 800-282-2848
    Sony ...................... Sony CD-ROM hotline ... 408-894-0555
    Sony ...................... Sony CD-ROM BBS ....... 408-955-5107
    Sony ...................... faxback service ....... 408-955-5505
    Sparco Communications ..... General ............... 800-840-8400
    Sparco Communications ..... General ............... 601-323-5360
    Sparco Communications ..... e-mail ................ sparco@sparco.com
    SparkWare.................. BBS ................... 901-382-5583 16800bps
    Specialix Inc ............. General ............... 408-378-7919
    Specialix Inc ............. UK .................... 44-0-932-354254
    Spectra Publishing......... BBS ................... 408-730-8326 2400bps
    SprintNet.................. BBS ................... 800-546-1000 2400bps
    SPSS ...................... BBS ................... 312-836-1900
    SPSS ...................... Sales ................. 800-543-2185
    SPSS ...................... Tech Support .......... 312-329-3410
    Stac Electronics .......... Tech Support .......... 619-431-6712
    Stac Electronics........... BBS ................... 619-431-5956 14400bps
    Star (Printers) ........... T/S ................... 908-572-3300 
    Star Micronics............. BBS ................... 908-572-5010 14400bps
    STB Systems ............... BBS ................... 214-437-9615 16800bps
    STB Systems ............... Fax ................... 214-234-1306
    STB Systems ............... General ............... 214-234-8750
    Storage Dimensions ........ Tech S Speedstor ...... 408-395-2688
    Storage Dimensions......... BBS ................... 408-944-1220 14400bps
    Summagraphics ............. T/S ................... 203-384-1344 
    Summagraphics ............. T/S ................... 800-729-7866 
    Sun ....................... Express ............... 800-USE-SUN 
    Sun ....................... Main Helpline ......... 800-USA-4SUN
    Sunrise Software........... BBS ................... 404-256-9525 2400bps
    Sunriver................... BBS ................... 512-835-8082 2400bps
    Supermac Software.......... BBS ................... 408-773-4500 2400bps
    Supra Corp................. BBS ................... 503-967-2444 14400bps
    Swan Technologies.......... BBS ................... 814-237-6145 14400bps
    Sydex...................... BBS ................... 503-683-1385 2400bps
    Symantec................... BBS ................... 408-973-9598 14400bps
    Symantec................... BBS ................... 503-484-6669 14400bps
    Syquest ................... ....................... 415-226-4000
   *Syquest ................... Fax Back .............. 800-245-2278
    Syquest.................... BBS ................... 510-656-0473 9600bps
    Sysgen .................... T/S ................... 800-821-2151 
    Sysgen..................... BBS ................... 408-946-5032 2400bps
    Systems Compatibility...... BBS ................... 312-670-4239 2400bps
  (T)
    T.A.G. BBS................. BBS ................... 313-582-6671 16800bps
    Tandy Corp................. General ............... 817-390-3011
    Tandy Corp................. Tech Support .......... 817-878-6875
    Tatung Co. of America ..... Tech Support .......... 213-979-7055
    Teac America, Inc. ........ Tech Support .......... 213-726-0303
    TEAMate.................... BBS ................... 213-318-5302 14400bps
    Tech Data ................. BBS ................... 813-538-7090
    Tech Data ................. Tech Support .......... 800-553-7977
    Tecmar..................... BBS ................... 216-349-0853 14400bps
    Telebit Corp. ............. Tech Support .......... 800-835-3248
    Telebit.................... BBS ................... 408-745-3803 14400bps
    Telix Support ............. BBS ................... 416-439-9399
    Telix Support.............. BBS ................... 416-439-8293 16800bps
    Template Garden Software... BBS ................... 212-627-5089 9600bps
    Texas Instruments ......... Tech Support .......... 512-250-7407
    Texas Instruments.......... BBS ................... 512-250-6112 2400bps
    TheComplete PC ............ BBS ................... 407-997-9130 14400bps
    TheComplete PC ............ Fax ................... 407-997-9621 14400bps
    TheComplete PC ............ Tech Support .......... 407-997-8062 14400bps
    TheSoft Programming........ BBS ................... 415-581-3019 2400bps
    Thomas Conrad.............. BBS ................... 512-836-8012 14400bps
    Thumper Technologies....... BBS ................... 918-627-0059 2400bps
    Thunderbyte USA............ BBS ................... 615-442-2833 14400bps
    Tiara Computer Systems..... BBS ................... 415-966-8533 14400bps
    Timeline Software.......... BBS ................... 415-892-0408 2400bps
    Timeslips.................. BBS ................... 508-768-7581 2400bps
    Tops microsystems.......... BBS ................... 510-769-8774 2400bps
    TOPS Support .............. BBS ................... 415-769-8874
    TopSoft Software........... BBS ................... 502-425-9941 16800bps
    Toshiba America ........... BBS ................... 714-837-4408
    Toshiba America ........... Tech Support .......... 800-999-4273
    Toshiba Printer Products... BBS ................... 714-581-7600 2400bps
    Trantor ................... BBS ................... 510-656-5159
    Trantor ................... FAX ................... 510-770-9910
    Trantor Systems............ BBS ................... 415-656-5159 2400bps
    Traveling Software......... BBS ................... 206-485-1736 14400bps
    Trident ................... BBS ................... 415-691-1016
    Trident ................... Tech Support .......... 415-691-9211
    Tripplite ................. T/S ................... 312-329-1601
    Trius...................... BBS ................... 508-794-0762 16800bps
    True Vision................ BBS ................... 317-577-8783 2400bps
    Tseng Labs ................ Fax ................... 215-860-7713
    Tseng Labs ................ General................ 215-968-0502
    TSR Systems................ BBS ................... 516-331-6682 2400bps
    Turbo Tax.................. BBS ................... 619-453-5232 2400bps
    TurboCom................... BBS ................... 503-482-2633 14400bps
    Turtle Beach............... BBS ................... 717-845-4835 14400bps
  (U)

    U.S.Robotics .............. Voice ................. 708-982-5151
    U.S.Robotics .............. FaxBack ............... 800-762-6163
    U.S.Robotics .............. CompuServe ............ GO USROBOTICS
    U.S.Robotics .............. Internet .............. support@usr.com
    U.S.Robotics .............. Sales & Marketing ..... 800-342-5877 
    U.S.Robotics .............. T/S ................... 800-982-5151
    U.S.Robotics .............. T/S Fax ............... 708-933-5552
    Ultrastor ................. BBS ................... 510-623-9091
    Ultrastor ................. General ............... 714-581-4100
    Ultrastor ................. Tech Support .......... 510-623-8955
    Unicore ................... General ............... 508-686-6468
    Unicore ................... General ............... 800-800-2467
    Unicorn Software........... BBS ................... 317-784-2147 2400bps
    UNIFACE Corp .............. General ............... 510-748-6145
    UNIFACE Corp .............. Support ............... 510-748-6445
    UniNova Service Corp....... BBS ................... 509-925-3893 16800bps
    US Sage.................... BBS ................... 417-331-7433 2400bps
    USNO Time of Day .......... BBS ................... 202-653-0351
    UUNET .....................     ................... 800-488-6386 
  (V)
    Ven Tel.................... BBS ................... 408-922-0988 14400bps
    Ventura Software........... BBS ................... 619-673-7691 14400bps
    Vermont Microsystems....... BBS ................... 802-655-7461 2400bps
    VESA ...................... FAX ................... 408-435-8225 
    VESA ...................... General ............... 408-435-0333
    Video Seven ............... T/S ................... 800-248-1850 
    Video Seven................ BBS ................... 510-656-0503 14400bps
    Virex...................... BBS ................... 919-419-1602 14400bps
    Visual Business Systems.... BBS ................... 404-953-1613 2400bps
    Volkswriter................ BBS ................... 408-648-3015 2400bps
    Vortex Systems............. BBS ................... 412-322-3216 2400bps
  (W)
    Wacom...................... BBS ................... 415-960-0236 2400bps
    Walker,Richer, & Quinn..... BBS ................... 206-324-2357 9600bps
    Walnut Creek (CDROM) ...... e-mail ................ info@cdrom.com
    Walnut Creek (CDROM) ...... FAX ................... 510-674-0821
    Walnut Creek (CDROM) ...... General ............... 510-674-0783
    Walnut Creek (CDROM) ...... General ............... 800-786-9907
    Walt Disney Software....... BBS ................... 818-567-4027 2400bps
    Wangtek ................... BBS ................... 805-582-3620 9600b
    Wangtek ................... Fax ................... 805-583-8249
    Wangtek ................... Fax Back............... 805-582-3381
    Wangtek ................... Voice ................. 800-992-9916
    Wangtek ................... Voice ................. 805-583-5255
    Wangtek.................... BBS ................... 805-582-3370 2400bps
    Wantree Development........ BBS ................... 913-441-0595 14400bps
    Weitek Corp. .............. Fax ................... 408-738-1185
    Weitek Corp. .............. General ............... 408-738-8400
    Weitek..................... BBS ................... 408-522-7517 2400bps
    Weltec .................... T/S ................... 714-669-1955 
    Western Digital ........... BBS ................... 714-753-1068 14400bps
    Western Digital ........... BBS ................... 714-753-1234 2400b
    Western Digital ........... France ................ 331-69-85-3914
    Western Digital ........... Germany ............... 49-89-922006-60
    Western Digital ........... Tech Support .......... 714-932-4900
    Western Digital ........... Tech Support .......... 800-832-4778
    Western Digital ........... UK .................... 44-372-360387
    White Water Systems ....... BBS ................... 708-328-9442 2400bps
    Word Perfect Corp ......... BBS ................... 801-225-4414 14400bps
    Word Perfect Corp ......... Tech Support DOS ver .. 800-541-5096
    Word Perfect Corp ......... T/S Mac ver 2.1 ....... 800-336-3614
    Word Perfect Corp ......... T/S Mac ver 3.0 ....... 800-228-2875
    Wordtech .................. BBS ................... 415-254-1141 2400bps
    Wyse Technology ........... BBS ................... 408-922-4400
    Wyse Technology ........... Tech Support .......... 408-435-2770
  (X)
    Xerox Computer Serv........ General ............... 213-306-4000
    Xircom..................... BBS ................... 818-878-7618 14400bps
    Xircom..................... Tech Support .......... 800-874-4428
    XTree...................... BBS ................... 805-546-9150 2400bps
    Xyquest.................... BBS ................... 508-667-5669 2400bps
  (Y)
    Young Micro Systems ....... General ............... 800-365-VEGA
  (Z)
    Zenith .................... T/S ................... 708-808-4300 
    Zenographics............... BBS ................... 714-851-3860 2400bps
    Zeos International ........ Customer Service ...... 800-848-9022
    Zeos International ........ Sales ................. 800-423-5891 
    Zeos International ........ T/S Fax ............... 612-633-4607
    Zeos International ........ Tech Support .......... 800-228-5390
    Zeos International ........ Upgrade Sales ......... 800-874-2943
    ZEOS Online Graphics BBS... BBS ................... 612-633-0815 
    Zoom Telephonics........... BBS ................... 617-451-5284 14400bps
    Zsoft...................... BBS ................... 404-427-1045 14400bps
    Zyxel Communications ...... BBS ................... 714-693-0762 
    Zyxel Communications ...... Service Center ........ 714-693-0804 


S) 10.0 Acknowledgments


Thanks to the following people for their contributions to the faq:

Carsten Grammes (cagr@rz.uni-sb.de), Mike Long (mike.long@analog.com),
Cameron L. Spitzer (cls@truffula.sj.ca.us), John M. Grohol
(grohol@alpha.acast.nova.edu), Jeff Abramson
(jabram@ichips.intel.com), Ronald Geens (rgeens@wins.uia.ac.be), Paul
Leslie Strople (strople@ug.cs.dal.ca), David Reeve Sward
(sward+@CMU.EDU), zeos@zeos.com, Steve Rusk (zz96sr@sdacs.ucsd.edu),
Arnoud Martens (arnoud@ijssel.hacktic.nl), Steve Walters
(swwalters@fl51mail.space.honeywell.com), comins@tecrus.enet.dec.com,
Frederick J. Ingham (p00736@psilink.com), Shaun Burnet
(burnesa@cat.com), John Anthony Ruchak (jruchak@mtmis1.mis.semi.harris.com),
Herbst OMR (herbst@techunix.technion.ac.il), Wayne Schlitt
(backbone!wayne@tower.tssi.com), Lee Fisher (leefi@microsoft.com),
Joeseph H Allen (jhallen@world.std.com), pieterh@sci.kun.nl,
Ron Bean (uwvax!astroatc!nicmad!madnix!zaphod),
Will Spencer (will@gnu.ai.mit.edu)
and the many others who helped bring the FAQ to where it is today.

===============
Ralph Valentino   (ralf@chpc.org)  (ralf@wpi.wpi.edu)
Hardware Engineer,  Worcester  Polytechnic  Institute
Center for High Performance Computing, Marlborough MA

