From: burgess@cynjut.infonet.net (Dave Burgess)
Newsgroups: comp.os.386bsd.announce,comp.answers,news.answers
Subject: [comp.os.386bsd] BNR/2 derived BSD for PCs FAQ (Part 6 of 10)
Date: 27 Dec 1994 01:00:29 -0600
Organization: Dave's House in Omaha
Message-ID: <386bsd-faq-6-788511609@cynjut.infonet.net>

Posted-By: auto-faq 3.1.1.2
Archive-name: 386bsd-faq/part6

Section 5.	(Kernel Replacements)

5.0	Introduction

	This section is supposed to document the unusual or optional
	kernel add-ons that are available from various places.  As 
	they are included in the mainstream of the various Berkeley
	Net Release systems, they will slowly come out of here.

	If you know of any replacement parts for the kernel, please 
	send Dave Burgess (burgess@cynjut.infonet.net) a message 
	detailing the package (possibly include a README), where it 
	can be found, and what version of the OS (ie. NetBSD, 
	386bsd 0.1 + pk 0.2, FreeBSD) it was designed to run under.


5.1	Available Kernel Replacements


5.1.1	keycap/codrv

	These server as replacements for the generic pccons driver
	that comes (by default) with 386bsd 0.1.

	Holger Veit (author of these) writes:

	"The same type of driver, but keycap has the version number 0.1.1
	and codrv has the version number 0.1.2.  The latter is much 
	improved and downward compatible.  Codrv was developed to provide
	a universal way of mapping national keyboard layouts during
	runtime (ie, not by patching the kernel tables) and providing
	better X11 support.  Codrv uses a superset of the pc3 terminal 
	emulation, and a termcap-like database for keymaps (therefore
	"keycap").  X11 is supported by two dedicated console raw devices
	/dev/kbd and /dev/vga, which avoids all the existing problems
	pccons has with X11.  The latest version has virtual consoles.
	Codrv will become part of patchkit 0.2.4"

	

5.1.2	pcvt

	A superset of pccons, this driver supports virtual consoles, 
	and some form of database oriented keyboard mappings.  It was
	also designed to emulate a vt220 terminal as best as possible.

	(This section originally identified Joerg Wuensch as the
	author. Hellmuth Michealis is the author of pcvt.  Joerg was the 
	author of the original post.  This update is from Hellmuth
	himself.  Apologies from the FAQ staff...)

	The last release of pcvt is version 3.00 and was done on March
	1st 1994 to the newsgroup comp.sources.misc, Volume 41, Issue
	140-152 (part 1-13).  Future releases and upgrades will be done
	as patches or new releases to that newsgroup.

	pcvt was recently put into the kernel sourcetree of
	NetBSD-current (pre 1.0) into /sys/arch/i386/isa/pcvt.

	pcvt is also available in the FreeBSD contributed tree at
	location /usr/ports/util/pcvt.

	The pcvt package consists of:

	- the driver itself
	- complete documentation for installation and operation
	- termcap/terminfo, pcvt.el, rc.local, /etc/ttys, xmodmap examples
	- cursor, utility to set the cursor size and shape
	- fed, a curses-based EGA/VGA character set editor
	- fontedit, utility to edit the VT220 downloadable character set
	- ispcvt, utility to display the drivers compile time configuration
	- kcon, utility to setup national keyboard layouts and remap keys
	- keycap, keyboard mapping database library similar to termcap
	- loadfont, utility to load up to 4/8 fonts into an EGA/VGA board
	- mcon, utility to control/configure a keyboard based mouse emulator
	- scon, utility to runtime configure the video part of pcvt
	- userkeys, utility to set the VT220 user programmable function keys
	- vttest, VT100 compatibility torture test program
	- demo, color- characterset- and attribute demos
	and more ....

	See the README-file for the latest release (3.00) of pcvt for
	lots more information and a complete list of the contributors
	to this project.


5.1.3	syscons

	Another superset of pccons that was designed to emulate SCO as
	well as possible.  Many of the ioctls from SysV have been 
	implemented.  XFree86 2.0 no longer requires special patches 
	to be run with kernels using this console driver.


5.1.4	Fast Symbolic Links

	The following is taken from the README for the fast sym-links
	patch:

	"This cruddy but complete hack answers one of the objections to
	 symlinks: that they are slow, and cost an entire frag.  Symlinks
	 of less than length 60 are stored in the inode itself.  Symlinks
	 longer than this are still in the inode.  To make the illusion
	 of normality complete, dump and fsck also need changing.  
	 Additionally, I made dumpfs verbose to excess."

	Fast Symbolic Links are supported natively in FreeBSD and NetBSD.


5.1.5	npx fixes

	There are problems with the floating point error handling 
	routines, and there are fixes available for this problem provided
	by Bruce Evans (of Minix-386 fame)

	Note that most of the code is applicable to floating point hardware
	as opposed to emulation.

	The newest version (and now official) fixes to this are in
	patchkit-0.2.4.

	There are still some nits in the npx emulation code in both FreeBSD
	and NetBSD.  They are being worked on.


5.1.6	CGD's COM drivers

	Chris G. Demetriou (cgd@blah blah blah) has written some COM 
	drivers for 386bsd.  These, among other things, support multi-
	port serial packages.

	This driver was the basis for the FreeBSD com subsystem.  NetBSD
	does not use them.  There are patch files around that added
	some of the missing functionality to NetBSD.  Multiport comm 
	support (the biggest and best feature of the CGD COM driver) is 
	included in both FreeBSD and NetBSD as standard 'compile in'
	features.


5.1.7	The original 386bsd 0.1 wd.c driver doesn't work. [386bsd 0.1
	only]

	If you are still using 386bsd 0.1 and are having trouble with
	the wd driver, Tom Helbekkno took the time to write a
	replacement wd driver specifically to fix the problems
	identified in the months after 0.1 was released.  Much of this
	code was pulled into the patch-kit.

	The 'Barsoom' driver was used as the basis for the original
	NetBSD and FreeBSD drivers, and was the source for much of the
	work that has been done to date on this driver.

	Unfortunately, the 'barsoom' driver is no longer available, and
	E-Mail from Tom indicates that there is very little of the
	original 'barsoom' driver left in either FreeBSD or NetBSD.  If
	you find yourself in this predicament, you REALLY need to
	upgrade to either FreeBSD or NetBSD.


5.1.8	Interruptless LPT Driver Kit [386bsd 0.1 only]

	This driver was designed with faster performance and lower system
	load in mind.  See the INSTALL-NOTES that come with the package
	for more details and installation information.

	This is also included in NetBSD and FreeBSD.  Note that with some
	printers, it may be prefereable to ignore the status port and rely
	on the data port.  If you have tried everything else and the
	interruptless printer driver still does not work for you, you may
	need to play with this.

	It has also been determined that the interruptless driver may be
	(or already has been) removed from the system.  A newer lpt driver
	has been developed that removes many of the overhead problems that
	the original 386bsd lpt driver had.


5.2	Floppy Disk problems.

	One of the most common problems in 386BSD involves working with 
	new boot sector and/or reformatting a floppy.  Dave Silvia 
	provided this section on using floppy disks.


5.2.1	How do I get a bootable floppy?

	Several ways, ranging from brain-dead-but-works to simplest.  
	Classification into categories is left to the reader (is there 
	really a difference between 'brain-dead' and 'simple'?:')

	1) rawrite (or dd) dist.fs (or fixit.fs) to a disk,
	   mount it, cd to the mount point, and execute:

		rm -rf .

	   you now have a bootable floppy!;^}

	2) Take your existing dist.fs or fixit.fs boot disk and
	   diskcopy it on a DOS machine.  Mount and rm as in 1)
	   above.  Again, you have a bootable floppy!;^}

	3) Run disklabel on the floppy, e.g.:

		disklabel -w -r fd0a floppy5

	   where 'floppy5' is a 'name' for an entry in the /etc/disktab
	   file.  You'll get a couple of ioctl errors because writing a 
	   label to a floppy isn't supported (yet?), but the boot blocks 
	   have indeed been written.

	4) Write the boot blocks to the floppy:

		cat /usr/mdec/fdboot /usr/mdec/bootfd | dd of=/dev/rfd0a

	   or, more simply:

		cat /usr/mdec/fdboot /usr/mdec/bootfd > /dev/rfd0a

	Methods 3) and 4) require you to run newfs on the floppy, e.g.:

	newfs /dev/rfd0a floppy5

	If you have a floppy that was originally bootable, but the boot
	blocks were somehow damaged, you can use method 3) or 4) to
	restore boot-ability (do _NOT_ run newfs).  You _could_, through
	the convolutions of copying a floppy whose boot blocks are damaged
	to a temporary location and then re-copying to a bootable floppy,
	use method 1) or 2) (if you really want to!;^})

	5)  If the disk is already newfs'ed and is otherwise ready to use,
	disklabel will write the boot blocks on the disk.  Read the man page
	for disklabel.


5.2.2	How do I maximize the space on a mountable floppy disk.

	As you all know, when you are working with a floppy, it is usually
	more important that the floppy have a lot of room, rather than a
	lot of other 'stuff'.  Here is the magic incantation that will
	maximize the amount of free space on the disk.

		newfs -Tfloppy[35] -i[4096 | 8192] -c 80 /dev/fd[0|1]a

	This leaves the disk with fewer inodes and only one cylinder group.


5.3	Character Device Driver info

	These devices are also often referred to as character devices.
	
5.3.1	Printers

	Configuring a parallel printer for 386bsd requires a working 
	printer driver to be installed in the kernel.  386bsd 0.1 does 
	not include a printer driver in the stock distribution kernel.
	NetBSD and FreeBSD both include this driver in their stock 
	manifestations.

	It is possible to connect a serial printer to either.  This brief
	tutorial is provided by Daryl Berryhill 
	(djberry2@b25info.b25.ingr.com)

	The way I got my printer to work.

	1) connect a 25 pin to 9 pin null modem cable to printer and 
	   computer.
	2) set printer to 9600 baud, 7 data bits, even parity.
	3) configure /dev/com1 (DOS COM2) port the same way as the printer
	4) add a line to /etc/printcap that says:
	       lp|local line printer:\
	          :lp=/dev/com2:wq:sd=/var/spool/lpd:lf=/var/log/lpd-errs:\
	          :br#9600
	5) type "lpr <add filename here>"
	6) type "lpd"
	   and it should start printing.

	An obvious point, but make sure that you do NOT start a getty on 
	on the com port.  Check the /etc/ttys file and make sure that 
	the com port you select is not active.

	There have been many reports in the past of people not being able 
	to get their parallel port printer working.  One of the problems
	seems to be cables.  Another problem may be with the hardware.  
	A seemingly stupid suggestion is to replace your printer card with
	the cheapest parallel port card you can find.  I am using a $10
	single parallel, two serial port card that I got from Altex.  
	Works great.

	In addition, there are people that want to set up multiple printer
	queues using the BSD queueing mechanism.  Here is a brief tutorial:

	Lpf is mainly intended for processing text and nroffed output...it 
	isn't anything clean...it will do certain games that will mess up 
	PCL output.

	If you're producing straight PCL or Postscipt (assuming your LJ 
	takes it), then you want to print directly to the printer w/o any 
	processing.  

	What you really want is a "physical" queue that does no processing, 
	and several logical queues that map back to the physical queue and 
	do processing...or one "smart" queue that does file content 
	recognition and then maps to the raw queue.

	I do something like this for my DeskJet.  There is one raw queue 
	and several logical queues (some postscript that do different 
	resoultions and color depth, some text that do various formatting, 
	etc).  When I get the time I'll be trying to set up a "smarter" 
	queue using aps and maybe some bits from flexfax.

	To map logical to physical queues either use a filter that pipes 
	back into lpr -P<rawqueue> itself, or just point it at the "raw" 
	queue using something like:

	textlp|Text Printing:\
	    :lp=/dev/null:\
	    :if=/usr/libexec/lpr/lpf:\
	    :rm=localhost:\
	    :rp=lj.raw:

	And other entries as needed, you get the idea...to use an output 
	filter instead of the rm/rp approach (more efficent), you can get 
	away with something like:

	    :of=/usr/local/bin/printraw:

	where /usr/local/bin/printraw looks like this:

	#!/bin/sh
	cat | lpr -h -Plj.raw


5.3.2	Terminals/Keyboards

	Terminals are relatively simple to add.  It involves making sure the 
	/etc/ttys file identifies the com port (com0, com00, or tty00 
	depending on your configuration) as an active port and a getty is
	running.  The man page for ttys and getty help explain this.

	Many people report that there are sometimes problems running some
	programs on a remote terminal.  There are some known bugs in the
	terminal handler where the parity and bits per character are 
	concerned.  They are being worked on.


5.3.3	Modems

	How to add a modem to 386BSD:

	The first part that confused me was assuming that /dev/com1 is 
	the same as DOS com1, they're not.  /dev/com0 is connected to 
	COM1 and (I think) /dev/com1 is connected to COM2.

	The switch settings for my modem were the same as what I had 
	under DOS, CTS CD RTS et al were set to follow the actual line 
	(i.e. my modem can force them high, which I turn off)

	Ok that's not too bad.

	Now you need to edit the /etc/remote file to include a reference 
	to the com port. I have only used NetBSD-0.8, so I'm not sure 
	what the default files are like that come with the other rev's 
	of 386BSD.

	I added the last line (with com0).
	--------------------------------------------------------
	#	@(#)remote	5.2 (Berkeley) 6/30/90
	#

	...stuff deleted...

	# UNIX system definitions
	unix1200|1200 Baud dial-out to another UNIX system:\
		:el=^U^C^R^O^D^S^Q:ie=%$:oe=^D:tc=dial1200:
	unix300|300 Baud dial-out to another UNIX system:\
		:el=^U^C^R^O^D^S^Q:ie=%$:oe=^D:tc=dial300:

	...stuff deleted...

	dial2400|2400 Baud Hayes attributes:\
	        :dv=/dev/tty19:br#2400:cu=/dev/tty19:at=hayes:du:
	dial1200|1200 Baud Hayes attributes:\
	        :dv=/dev/tty19:br#1200:cu=/dev/tty19:at=hayes:du:
	
	# Hardwired line
	com1c|com1:dv=/dev/com1:br#9600:
	com1b:dv=/dev/com1:br#2400:

	com0:com0:dv=/dev/com0:br#9600:at=hayes:
	------------------------------------------------

	Ok, now if you are running as root you can use type 'tip com0' 
	and you should then be talking to your modem.  I use kermit to 
	transfer files, and it wants to create a lock file in (not sure 
	about the exact path) /var/spool/uucp/lock or something along 
	those lines.  I made the directory world writeable so I could 
	run kermit with my own uid, rather than root.

	Also, you may need to add an entry in /etc/remote for com0.

	Thanks also to thombsr@liciren.li.co.uk for information on how 
	to do this.

	New problems have surfaced with the latest releases of NetBSD.
	It seems that the paradigm that the com port used to use was
	'less than complte' and much of the code has been replaced. 
	This provides for some interesting new problems.  The first is
	that the Carrier Detect line is no longer ignored, as it was
	before.  This means that programs like kermit and tip/cu either
	have to be told explicitly to ignore the CD line (in kermit,
	for example, you would use the 'set carrier off' in your .kermrc)
	or you need to use the 'stty -f /dev/com? clocal' command before
	you open the port.

	If you have trouble getting the settings to 'stick' it is because
	the ports are now initialized to known settings on the last close
	of the port.  A workaround for this is to use the command:

		sleep 1000 < /dev/com?
		tip ...
		 { or }
		kermit ...

	This will keep the port open for about 12 minutes while you do 
	whatever it is you need to do.  Once the port is open and your
	connection established, the port will not reset until the final
	close.

	Another symptom of this malady is described below.

	When I 'set line' in kermit, it hangs until I hit my escape
	character (^\).  It *does* set the line (and the rest of my session 
	is normal), but it's annoying because I can't put 'set line' in
	my .kermrc. 

	The answer is available in the kermit documentation as well as
	here (now).  The following commands are MY .kermrc file:


		set carrier off
		set line /dev/com2
		set speed 38400
		set modem hayes
		set dial speed on
		set dial timeout 60

	The 'set carrier off' tells kermit to ignore the Carrier Detect
	line from the modem, and to proceed as if the command were
	there.  This will (as far as I have ever been able to find
	out) fix the specific problem with not being able to set the
	line.
		

5.3.4	What is the trick for getting Kermit to work with rz and sz?

	Add these lines to your .kermrc file.  They should do the trick.

	define sz !sz \%1 \%2 \%3 \%4 \%5 \%6 \%7 \%8 \%9 < \v(line) > \v(line)
	define rz !rz \%1 \%2 \%3 \%4 \%5 \%6 \%7 \%8 \%9 < \v(line) > \v(line)


5.4	Tape Drives

	This section should help out for those of you that have either
	never used tape drives before, or only have experience with them
	as non-Unix devices.


5.4.1	Does the tape need to be formatted?

	It depends, but I think usually not.  And when it is necessary,
	I don't know how it would be done.  One thing is for certain, 
	though, first....  NEVER use the block devices..  erase them and 
	forget you ever saw them.  All operations on tape should be to 
	the character device (rst0).


5.4.2	If I execute the command 'st -f /dev/st0 status', I get:
		Archive/Tandberg? tape drive, residual=0, blocksize=512
		Density: high = 16 (0x10), medium = 15 (0xf), low = 5 (0x5)
		ds=0
		er=0

	so to write to tape at high-density (QIC-150), presumably I want 
	to use a device with minor number +4 (in st.c, density is computed as
	minor >> 2 & 0x03, where low density == 3 and high == 1):

	You have the idea.. density is controlled by bits 2 and 3

		00 = default
		01 = hi density
		10 = medium density
		11 = low density, 

	Unless the driver knows about you kind of drive the density values
	may need to be set by hand before they make any sense.


5.4.3	When is erst0 used?

	e stands for 'eject' and is bit 1 of the minor.. 
	e.g. eject on close.. many devices can't actually do this.

	There is actually a method to this whole thing:

		r = raw		(rst0)
		e = eject	(erst0)
		n = No rewind	(nrst0 or maybe nerst0)


5.4.4	How is density (bpi) computed?  I am using 3M DC 6250 cassettes 
	which have a 250MB capacity on the Viper 150.  But computing the 
	bits/inch based on 250MB/tape-length (1020 ft.), I get a density 
	of 171335 bpi, which is nowhere near the 10000 bpi associated 
	with QIC-150 in the st(1) man page.  Why the discrepancy?

	These cartridge tapes are written in narrow tracks which 
	alternately begin at opposite ends of the tape.  Track 0 starts 
	at the beginning of the tape, and Track 1 starts at the other 
	end, etc.

	So, how many times does the tape go backwards and forwards?  If 
	there are 17 tracks, your density is 170000 bpi if it is 10000
	bpi per track.  The more tracks, the lower the bpi/track.


5.4.5	How is an appropriate block size determined (and in what units 
	are they specified in the st(1) command)?

	QIC 150 and below should stick to 512 byte blocks a write of 
	1024 bytes from the program will be written as 2 512 byte blocks 
	with no speed penalty.  dd will think it's writing a 1024 byte 
	block but on tape it's 2 x 512.

	Stick to 512 on QIC 150 or less if you ever hope to swap data 
	with anyone else.


5.4.6	From the 4.3BSD mtio(4) man page, it sounds like data is typically
	(traditionally?) stored on tape in eof-terminated sequences of 
	1K records.  

5.4.6.1	Is st's notion of "file" the record sequence between two eof marks?  

5.4.6.2	What about a "record"?  

5.4.6.3	Is a "record" one "block", as determined by st's "blocksize" command?   
	If not, what is the connection between them?  

5.4.6.4	Can I change the "record" size?  
5.4.6.5	When would I want a block size that is different from the default?  
	1KB is the size of writes used by dd or whatever.  QIC specifies 
	512 byte records (well at least its what people use..)  Whatever 
	you write in will be broken into 512 byte sections.  They must be 
	multiples of 512 though.

	If you have written to a tape, a close will automatically append a 
	filemark (eof mark).  You may read the 512 byte blocks back as 
	512 byte records or as 1024 byte records (in which case you'll 
	get 2 at once).  The bigger the unit, the more efficient.

5.4.7.1	How do I write several archives to a single tape?  I tried without 
	success:
		$ st -f /dev/rst4 rewind
		$ tar cf /dev/nst4 archive1
		$ st -f /dev/nrst4 weof
		$ tar cf /dev/nst4 archive2
		$ st -f /dev/nrst4 weof

	First:  throw away the block devices.

	'n' stands for 'No-Rewind-on-close' and will leave the tape 
	positioned ready for another file e.g.

		tar -cf /dev/nrst0 archive1
		tar -cf /dev/nrst0 archive2


5.4.7.2	Later, I would expect to be able to access, say, archive3 via the fsf
	directive to skip over the first two archives.  What is the correct
	sequence?

		st -f /dev/nrst0 rewind
		st -f /dev/nrst0 fsf 2
		tar -xf /dev/rst0 {files}


5.4.8	Since the Viper 150 writes on QIC-150/120, I guess I don't need 
	to worry about writing variable-length records?  How about reading 
	a tape written with variable-length records.  Is this possible 
	with the Viper?  If so, what's involved?


	Who would have written it? :-)

	Presently you can't.  You`re right.  Don't worry about it.

	The new 'st' changes will change this somewhat, though.


5.4.9	The very scant documentation that came with my drive mentions
	a "selectable buffer disconnect size," whose default is 16K.
	This is evidently the "maximum number of bytes that can be 
	sent over the SCSI bus during a single data transfer phase."  
	What's that?  How is it connected st's "blocksize" command?  
	Do I want to use 16K blocks, or might I even want to set the 
	disconnect size to a higher value?

	This suggests that 32 512 blocks will be written at a time.
	This jives with the tape format for some of the lower density 
	cartridges (QIC-40 and 80, for example).  The tape is written 
	in blocks of 32 512-byte blocks, with the last three being used
	for Error Correction Codes.  

	Use dd or tar with 16 k blocks and 32 x 512 byte blocks will be 
	written.

5.4.10	What is "streaming"?  When I tar a directory of files to tape,
	I notice that the tape often stops.  Streaming means it doesn't 
	stop?  How would I get the viper 150 to stream using tar or cpio 
	or dump?

	Use a bigger write size... (more efficient)  Try 16k blocks.


5.4.11	Where are all the answers to the above and related questions 
	written down?  Neither on the net nor in the 4.3BSD manuals 
	nor Administration text which I have could I find this stuff 
	covered!

	They are in the FAQ :-)...


5.4.12	What else should I know?  For example, it seems that a new tape 
	must stretched.  How is this done?

	Use a blowtorch and a pair of pliers;  or you can use the 
	non-destructive method and run the tape through a complete fast 
	forward/rewind cycle to get it tight on the spindles.


5.4.13	My tape drive doesn't work.  

	OK.  There are lots of reasons why it may not.  The most obvious is
	that there are no devices associated with the device in the kernel.
	You can check this through the use of the 'dmesg' command.  Look
	for tape drives.

	If your tape drive is connected to your floppy controller, it may
	or may not be supported.  Several manufacturers of QIC-40/QIC-80
	minicartridge drives are supported natively in FreeBSD and 
	experimentatlly in NetBSD.  Some aren't (mine for example, is not).

	If your tape drive is a SCSI based drive, your guess is as good as 
	mine.  I don't have one.


5.5	Network

	Network devices for NetBSD and FreeBSD include many types of
	Ethernet cards, as well as Serial Line IP and Point to Point
	Protocol.

5.5.1	How can I get my system to work as a network router?

	The first hurdle to overcome is that the default kernels do not
	have the GATEWAY option compiled in.  Without this, it is very
	nearly impossible to use the kernel as a router.

	Once you have the GATEWAY option compiled in, all sorts of things
	magically start to work.  

5.5.2	I recently has a problem where I got a message that said "panic: 
	kmem_malloc: mb_map too small".  What is the solution to this
	problem?

	The second hurdle is that sometimes you run out of cluster 
	allocation space in the kernel. This is probably network-related 
	and usually shows up when something is being done using the 
	network (like NFS).  The way to get around this would be to 
	change the value of NMBCLUSTERS in your config file. NMBCLUSTERS 
	is set at 256 by default, and increased to 512 when the GATEWAY 
	option is active. To be very safe, you could add

		options         NMBCLUSTERS=1024

	to your config file, and recompile. This is reported to work
	with systems that crashed as soon as a large number of people 
	(75+) were connected to it.

-- 
TSgt Dave Burgess           | Dave Burgess
NCOIC, USSTRATCOM/J6844     | *BSD FAQ Maintainer
Offutt AFB, NE              | Burgess@cynjut.infonet.net or ...@s069.infonet...
                               

