jkg@gitpyr.gatech.EDU (Jim Greenlee) (11/24/86)
I am cross-posting this to several newsgroups to get as wide an audience
as possible. It mainly relates to CP/M, but there is some MS-DOS stuff
which I'll take care of at the beginning here. Topics include:
Running CP/M programs (particularly CB-80) on PC compatibles with V20/30s
{ CP/M | Z80 | S100 } based computer hardware (particularly Dynabyte and
Osborne 1 computers)
In article <9519@lanl.ARPA> myxm@lanl.ARPA (Mike Mitchell) writes:
>In response to those wondering if CP/M emulation is available on the
>8088, 8086, etc.-- there is a fine emulator program available on many
>bulletin board systems areound the country. It is called Z80MU and it
>emulates a CP/M machine running CP/M 2.2.
>This program was reviewed in the Oct 86 Byte on page 203. I would
>recommend that you folks take a read on this article. The major
>difficulty that I found with this program is getting the CP/M stuff
>onto a DOS diskette.
I read this article, and it looks interesting. Does anyone have a copy of
it they'd care to e-mail to me? I have UUDECODE and ARC, so that format is
preferred.
Help question number 1:
Does anybody know anything about the NEC V25 which is mentioned at
the end of said article? Will it be offered as an 8086-compatible
part (V35, maybe?)
In response to my recent request, Kees Huyser kindly e-mailed me a program
called V2080.COM that uses a NEC V20/30 in 8080 emulation mode to run CP/M
compatible software. I have spent most of this weekend playing around with
it on my AT&T 6300, and I wanted to summarize my findings and ask for some
assistance.
The program works as advertised - in fact it works better than I expected.
I have a Z80-based S100 system manufactured by Dynabyte (anybody who knows
anything about Dynabyte computers, PLEASE keep reading :-) and I managed to
port a bunch of programs to my PC. I used the old serial transfer method
as follows:
I connected my PC to the terminal output of my Dynabyte and, using Procomm
with the logging feature on, I ran the CP/M DUMP utility to capture the file
to my hard disk. I then hacked up a program in Turbo Pascal to read the output
of DUMP and convert it back to a binary file. This was the only way I could
get the programs over because the only communications software I have for
the Dynabyte is Crosstalk version 1.0 (this is no joke), which, to my know-
ledge, doesn't support binary file transfer directly.
The first thing I tried was MBASIC interpreter. It worked flawlessly. I then
copied over most of the CP/M utilities, such as ASM, DDT, PIP, STAT, and ED.
ASM, DDT, and PIP worked pretty well, too. STAT and ED gave me some problems,
though. STAT always returns something like "A: R/W, Space 358k" no matter how
much free space is available. It also returns error messages if you try to
do a STAT DEV: or a STAT VAL: - I didn't really expect these to work - I
don't think MS-DOS has an equivalent to IOBYTE. ED is pretty much all screwed
up, but who uses ED, anyway? :-)
So, I spent some time playing around with ASM and DDT and generally thinking
I had been time-warped back 5 years. I had forgotten how much fun CP/M was!
Then, remembering that someone had recently posted a request for a CB-80
compiler for the IBM-PC, and feeling pretty ambitious and worldly, I decided
to transfer my CB-80 compiler over to see what would happen. My hopes were
dashed when I got a "create error:" immediately after pass 2 on a small test
program.
Help request 2:
Does anybody have any idea what would cause this? The documentation
says that it is usually due to a full disk directory, but I managed
to create and save a small program file from within MBASIC without
any problem. It seemed to interact with the DOS file system just fine.
There is probably some quirky incompatibility, but I don't have the
patience to go through the compiler object code to find it - it uses
3 overlays (remember overlays? :-) that are all about 20k in length.
I have no idea where the error is occurring. I am not that familiar
yet with MS-DOS (I have version 3.1) to ferret out the cause of the
problem - maybe somebody who is familiar with both OSes can help me.
OK, since the rest of this posting deals mostly with stuff that is unrelated
to MS-DOS/IBM-PC, disinterested parties should hit 'n' or whatever.
As I mentioned above, I have a Dynabyte DB8/1 computer (model 5100 or some-
thing like that). I am interested in hearing from ANYBODY who has one or
knows anything about them. I got a good deal on it used, but it is really
flaky. The "kernel" system works OK most of the time (Z80 CPU, FD controller,
2 Shugart 801s, 64K RAM), but the system has a hard disk that crashes with
great frequency.
The hard disk is an 8 inch Fujitsu MA2301A (11.7 Mbytes unformatted). I can
format the disk OK with any of several partitioning schemes (I generally
use the 5 Mbyte/5 Mbyte partition) but after a while I get the infamous
"Bdos error on drive x:" message. It acts like there are a couple of flaky
tracks in the directory. I tried swapping them into the bad track table and
reformatting the disk, but eventually it crashes again.
I suspect that the head positioning mechanism needs adjusting - it sounds
like a hamster's exercise wheel whenever it seeks. Does anybody know if
these drives are serviceable? I would prefer someplace in Metro Atlanta,
but I don't want to pay an arm and a leg. Any info/advice on this drive
would be appreciated. Is it plug-compatible with anything?
I think Dynabyte is still in business. I talked to somebody out there about
2 years ago and got a lot of good information and an upgrade to version 3.3
of their OS, which is a superset of CP/M 2.2. I was told that Data Decisions
in Tempe, AZ has a third party maintenance contract on old Dynabytes, but
their repair charges were cost prohibitive. I also tried Sorbus, Xerox, TRW,
and a bunch of local folks, but all I got were blank stares (Dyna-who?).
The system ran MP/M at one time, and I have 2 additional 64K RAM cards, but
no other spares.
I bought the system mostly to goof around with. I want to try building and
bringing up an 80x86 or 680x0 card on it, but it is pretty much unusable in
its present condition.
Help request 3:
Anybody who ever heard of Dynabyte, please e-mail!
Finally, Osborne 1 experts, this is your hour! I have a friend who cannot
get to USENET, so he asked me to post this. Does anyone know how to fix an
Osborne 1 to run off of 50 Hz? He claims it will run off a car battery, so
everything (drive motors, etc.) must be DC, but he seems to think that there
may be some problem with the vertical sync on the monitor. Does anybody out
there have any ideas?
Help request 4:
How do you convert an Osborne 1 to run off 50 Hz?
I know this got rather long-winded, but I am really desparate for the above
information. Any help would be appreciated!
Jim Greenlee
--
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