Date   : Tue, 02 Jun 1987 16:07:13 ULG
From   : Andre PIRARD <A-PIRARD%BLIULG12.BITNET@wiscvm.wisc.edu>
Subject: CP/M on the V20

I started microcomputing on a self built CP/M machine (I wrote my
own ROM and BIOS). Now I own an IBM PC clone in which I plugged a
V20 chip. Of course I'd like to be able to use it to run CP/M.
I  have tried several software emulators,  but just one using the
V20, giving a mere 52K TPA. They are of several type:
1) stubs to concatenate ahead of a CP/M load module.
2) simulators executing the filename in the parameter line.
3) emulation of a CP/M environment with CCP.
Completeness of the simulation varies.  Some features such as get
allocation vector (function 1B) or BIOS physical disk access  are
virtually impossible to emulate when using MSDOS disks and files.
But  many miss the point that if MSDOS returns code 3 to  a  file
read  (partial  record read,  filled with zeroes),  it should  be
translated to 0. That's why I feel best to own source code.
I  like  to have the complete CP/M environment,  but  solution  1
gives  the best of both worlds if one concatenates the stub to  a
relocating and reloadable CCP.
I  have  read  an  article stating that GFI sells a  V20  type  1
product with source code.  It achieves the tremendous TPA size  I
am  looking  for,   but  the  sample  code  listed  was  not  too
encouraging. Any comment?
Is there anything available in the public domain? I wouldn't mind
spending  some  time  adapting  a CCP to  a  type  1  stub.  Some
additional MSDOS commands such as change path would be useful.
Thanks in advance.
Andre PIRARD
SEGI - Universite de Liege
15, av. des Tilleuls
B4000 LIEGE (Belgique)
+32 (41) 520180(449)
Bitnet:  A-PIRARD%BLIULG12
Arpanet: A-PIRARD%BLIULG12.BITNET@WISCVM.WISC.EDU