            GETTING DOWNLOADED FILES TO WORK UNDER C128 CP/M

So you want to get started using the OTHER cpu in your 128: the Z80 chip.  
You've heard, from the manuals and elsewhere, that there is loads of CP/M 
software available, the vast majority of which you could use on your 128.

So let's say you find a source of CP/M software.  Library #27 on GEnie's
C64/128 Flagship, where this file was located, as well as the CP/M RoundTable
on GEnie, is probably a good place to look.  But your terminal program
downloads files in the 128's native mode, producing commdore (C=) PRG or SEQ
disk files- which are not directly readable by CP/M.  So how do you get these
files into CP/M format?

To start, you will find the program CrossLink2.1b quite helpful.  This program
runs in the 128's native mode- meaning you aren't stuck with the catch-22 of
having to convert a file conversion utility.  It will read and write C= 5.25"
disks (with a 1541 or 1571) as well as CP/M single sided and double sided
disks.  (It claims to read and write MS-DOS disks as well, although I have not
tried this myself.)  This way, if you have a disk you have formatted under
CP/M (using the utility FORMAT.COM included on your CP/M system disk), you can
translate files on CBM disks to a format readable by CP/M.

Eventually, you will probably want the CP/M program RDCBM.COM (version 2.1).
This CP/M program reads C= disks.  It has one major advantage over Crosslink:
there is no limit to the size of files it can read.  Crosslink can only
read/write files up to about 45K in size.  RDCBM.COM also supports the CP/M
RAMdisk, if you have a 1750 REU (which I heartily recommend if you use either
CP/M or GEOS much).

So now you have the files readable by CP/M.  But wait!  All of these files
have funny extentions like .LBR and .ARK, or .CZM instead of .COM.  And you
try to run them- and nothing happens!  That is because these are compressed or
archived files, which need to be uncompressed or dearchived before they can be
used.
 
But how do you convert them to a usable format?  The standard commodore 
utilities in general won't work on CP/M files.

The first file you will need is UNARC16.ARK (perhaps called UNARC16.SDA).  This 
program will dearchive .ARK files.  It is a self dissolving archiver itself 
(i.e. you don't need it to get it).  Rename it to UNARC16.COM, and run it like 
any other CP/M program.  This finished, you will have a DeARKiving utility.

Next, you will probably want to get ahold of some library and uncompressing
utilities.  I would recommend for most uses LT31, a utility that will extract
files from libraries and decompress all of the common compression formats
seen in CP/M.  With just LT31 and UNARC16 you should be able to dissolve all
CP/M archives you find.

If your tastes don't run that way, there are individual library and
decompression utilities you can use.  DELBR12.ARK is a must, if for no other
reason simply because you will need it to dissolve LT31.LBR.  You can use
UNARC16 to dissolve the DELBR12.ARK.  NULU152A is a more powerful library
managing utility, which will allow you to create as well as dissolve
libraries.  Also, there are individually compacted files.  Files with
extentions .?Z? (the ? meaning any character) are "crunched," and files with
extentions .?Q? are "squeezed," and files with extentions .?Y? are "lharced."
Sometimes you will find compacted files inside a library (.LBR file).  In
order to unsqueeze and uncrunch files, you will want the utilities USQ120.COM
and UNCR-Z80.COM.  LT31 is probably your best bet for dealing with lharc'ed
files.

Once you have these files, you have everything you will need to get started
taking advantage of the large amount of public domain software available for
CP/M.  And at this stage you might want to look into the wonders of ZPM and
ZCCP... I won't distract you by discussing that here, but will rather refer
you to the text file which introduces all that.  Meanwhile, enjoy!

Robert Knop (R.KNOP1)

