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Number 2 February,1981 Volume 1, Issue 2
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Printed monthly (at worst quarterly) to inform user's of
RCPM Systems to the latest software news, information, and
updates of public domain software accessible via
telephone/modem transfer. Yearly subscription for copies of
the CP/M-Net News may be obtained by mailing $18.00 (check
or money orders only) to Kelly Smith, CP/M-Net, 3055 Waco
Street, Simi Valley, California 93063. CP/M-Net is a non-
profit orginization and all money received on subscriptions
are utilized for the sustaining and enhancments of the CP/M-
Net System.
If you would like to contribute an article, include a
column containing your area of interest and expertise, or
participate in an open forum for conversation and transfer
of ideas, feel free to send it to the CP/M-Net System and
indicate that you would like it to be included in the CP/M-
Net News...if possible, use WordStar (trademark, MicroPro
International) or Electric Pencil (trademark, Micheal
Shrayer) in 60 column format.
NOTE: CP/M is a registered trademark of Digital Research
Microsoft MBASIC.COM version 5.03 [CP/M Compatible]
Reported By: Kelly Smith, January 11, 1981
Application: Any
When utilizing the SAVE function under MBASIC.COM version
5.03, DO NOT use lower case for the filename...it will be
placed in the CP/M directory in lower case, and any
subsequent attempt to "read-it-in" again with MBASIC will
result in a "File not found" error! The only way to get rid
of it (kill it in the directory) is to ERA *.BAS<cr>, and
this will (of course) clobber all other ".BAS" files. Sam
Singer's DUMP.COM (CPMUG Volume 14.7) program can also be
used to "erradicate" the file...
What to do about CP/M's "SYNCRONIZATION ERROR"
(SYSGENing CP/M Version 2.2, from Version 1.4)
by Kelly Smith, CP/M-Net "SYSOP"
Question:
"How in the #*@%! do I SYSGEN CP/M Version 2.2 on my CP/M
1.4 system, when using it's MOVCPM (to generate a new system
image), and the &%#"*@ thing keeps coming back with
SYNCRONIZATION ERROR, and then promptly HALTS!"
The Problem:
Those clever people at Digital Research have embedded the
serial number (issued to YOU I hope!) in MOVCPM.COM, to
discourage the "rip-off" of CP/M by someone other than the
rightful owner...when MOVCPM is executed, it looks for a
match of it's serial number to that of the host system (your
CP/M Version 1.4) as it appears in your system memory,
detects that a "mismatch" has occurred, and promptly locks-
up your computer...ARGH! "You mean I have to write that
crummy "GETSY" and "PUTSYS" stuff to SYSGEN from 1.4 to 2.2
???" we ask ourselves...
The Solution:
Fake-out #1...your CP/M Version 2.2 as supplied by Digital
Research, is SYSGEN'd for a 20 Kilo-byte Intel MDS 800
system...so write a 20 Kilobyte BIOS (and BOOT loader), then
do as follows to get a 20 Kilo-byte CP/M 2.2 system image...
A>B:<cr> <--- Switch from A (CP/M 1.4) to B (CP/M 2.2)
B>SYSGEN <--- Use CP/M 2.2's SYSGEN to get a system image
SYSGEN VER 2.0
SOURCE DRIVE NAME (OR RETURN TO SKIP)B <--- Get it...
FUNCTION COMPLETE
DESTINATION DRIVE NAME (OR RETURN TO REBOOT)<cr> <--- Return
A>SAVE 34 B:CPM20.COM <--- Save the CP/M 2.2 system image
O.K., now SYSGEN normally on the B drive, with your 20
Kilo-byte BIOS (and BOOT loader)...
Fake-out #2...Ah hah, so this is NOT your copy (I know,
your doing this for a friend...) of CP/M Version 2.2, and
it's been SYSGEN'd for something OTHER THAN a 20 Kilo-byte
system...double ARGH! All is not lost however, just follow
the (less than simple) sequence that follows using the
MOVPATCH.ASM file that is listed after the SYSGEN
sequence... A word of CAUTION however! Some implementations
of MOVCPM.COM NOT DIRECTLY SUPPLIED by Digital Research have
been "fiddled"...the address referenced in MOVPATCH.ASM that
follows WILL NOT be the same...Lifeboat Associates has
modified MOST versions of MOVCPM.COM that I have seen,
for particular applications (i.e., double density, etc.).
A>DDT B:MOVCPM.COM<cr> <--- Get the CP/M 2.2 MOVCPM in...
DDT VERS 1.4
NEXT PC
2800 0100
-IMOVPATCH.HEX <--- Set-up the MOVCPM patch
-R<cr> <--- Read it in
NEXT PC
2800 0000
-XP<cr> <--- We need to reset the program counter
P=0000 100<cr> <--- Set it back to address 0100 Hexadecimal
-G<cr> <--- Go execute MOVCPM...
CONSTRUCTING 56k CP/M VERS 2.2 <--- Making my system size...
READY FOR "SYSGEN" OR
"SAVE 34 CPM56.COM"
A>B: <--- It was faked-out, switch to drive B
B>SAVE 34 CPM56.COM<cr> <--- Save the CP/M 2.2 system image
B>DDT CPM56.COM<cr> <--- Bring in the new system image
DDT VERS 2.2 <--- The "new" DDT announcing itself...
NEXT PC
2300 0100
-ISBOOT56.HEX<cr> <--- My BOOT loader
-R900<cr> <--- Offset required for BOOT loader position
NEXT PC
2300 0000
-ICBIOS56.HEX<cr> <--- My 56 Kilo-byte BIOS
-R4580<cr> <--- Offset for 56 Kilo-byte BIOS position
NEXT PC
2300 0000
-G0<cr> <--- "Warm boot" your CP/M 1.4 system...
B>SYSGEN<cr> <--- Use CP/M 2.2 SYSGEN to generate the system
SYSGEN VER 2.0 <--- The "new" SYSGEN announcing itself...
SOURCE DRIVE NAME (OR RETURN TO SKIP)<cr> <--- Return
DESTINATION DRIVE NAME (OR RETURN TO REBOOT)B <--- Put on B
DESTINATION ON B, THEN TYPE RETURN<cr> <--- Return
FUNCTION COMPLETE
DESTINATION DRIVE NAME (OR RETURN TO REBOOT)<cr> <--- Return
A> <--- Return to your "old" CP/M version 1.4...
O.K., now remove the CP/M 1.4 disk from the A drive, and
remove the CP/M 2.2 from the B drive, insert it in the A
drive and do a "cold boot"...hereafter, MOVCPM will operate
normally, so no need to go thru the MOVPATCH routine...
MOVPATCH.ASM for MOVCPM.COM CP/M Version 2.2
Note: you MUST SET "msize" for your intended system memory
size to make this work...assemble normally with the CP/M
Version 1.4 "ASM.COM" file. MOVPATCH.ASM may not work
with copies of MOVCPM.COM that are NOT SUPPLIED by Digital
Research.
msize equ 56 ;put your memory size HERE...
org 05ch ;absolute file control block address
db 20h,'0'+msize/10,'0'+msize mod 10,20h
org 232h ;serial number string length check
xra a ;set flags
org 2c4h ;serial number match check
lxi h,1200h ;force MOVCPM to look at it's
;own serial number...
Loading DDT Without 'Clobbering' the CCP
by Kelly Smith, CP/M-Net "SYSOP"
January 25, 1981
From time to time, I need to do some 'special tricks'
within CP/M itself to modify it's operation to do something
other than what Digital Research had intended. If you
attempt to load DDT 'normally', it 'clobbers' the Console
Command Processor by overlaying it with DDT...making
modification (using DDT) impossible. This program will load
Digital Research's Dynamic Debugging Tool (DDT) without
overlaying the CP/M Console Command Processor, and works for
CP/M version 1.4 AND 2.0 through 2.2...Be sure and set the
equate MSIZE for your particular CP/M system size, for
proper operation...name it to something like 'DDTLOAD.ASM',
assemble and load...then execute it as follows:
A>DDTLOAD<cr>
DDT will now load into memory 'nomally', but will be
relocated BELOW the CCP. Here's the software to do it...
true equ -1 ;define true
false equ not true;define false
cpm14 equ false ;true if CP/M vers 1.4
cpm22 equ true ;true if CP/M vers 2.2
;
msize equ 56 ;must be set for YOUR CP/M system size
;
base equ 0 ;CP/M system base address
;
if cpm14
cbase equ base+2900h ;base of 16k CP/M 1.4 CCP
bias equ (msize-16)*1024 ;offset for system
nbase equ cbase+bias-10h ;new base address
endif
;
if cpm22
cbase equ base+3400h ;base of 20k CP/M 2.X CCP
bias equ (msize-20)*1024 ;offset for system
nbase equ cbase+bias-10h ;new base address
endif
;
org base+100h
;
lhld base+6 ;move old BDOS address to new BDOS entry
shld nbase+1 ;swap new base address into original base
shld base+6
mvi m,jmp ;make 'jump' opcode to new base address
lxi h,'3D'-'0' ;create DDT command in
;console input buffer
shld cbase+bias+7
lxi h,'DT'
shld cbase+bias+9
xra a ;make 'EOL' as null for message end
sta cbase+bias+11
mvi a,8 ;reset command pointer
sta cbase+bias+136
lda base+4 ;select current drive
mov c,a
jmp cbase+bias ;all parameters set, load DDT
Using CP/M's Undocumented "Autoload" Feature
by Kelly Smith, CP/M-Net "SYSOP"
Ever wished you could just slam a diskette into your drive,
boot it, and have it immediately start executing a program
for you...or the kids want to play some nifty game, but your
tired of having your diskettes trashed 'cause your 14 year
old boy does not understand the full implications of ERA
*.*...?!? Well here's a little known feature of CP/M that's
worth knowing...it has a BUILT IN AUTOLOAD!
I don't know why Digital Research fails to document this,
for public consumption (?), they include the information in
their OEM distribution documentation, but not anywhere
else...and how many of us are OEM distributers? Well, here
are the details of "autoload", and how to implement it on
your CP/M system.
First, take a "scratch" diskette and do a full disk copy of
your CP/M system diskette (this includes the system tracks).
If you don't have a disk copy program, SYSGEN the "scratch"
diskette and PIP all the stuff to it. Now, stick the new
diskette (to be set-up for "autoload") in drive A:, "warm
boot" it (Control-C) and let's assume that we want to
"autoload" Microsoft's MBASIC and have it execute
STARTREK...Here's what you do:
A>ddt movcpm.com<cr> <--- We need to "patch" MOVCPM.COM
DDT VERS 2.2
NEXT PC
2800 0100 <--- Write down '2800' someplace
-d0a00<cr> <--- Dump starting at address 0A00 Hex
Here is the start of CP/M (this is CP/M Version 2.2, but
this "method" will work for CP/M Version 1.4 just as well):
