Date   : Thu, 02 Dec 1982 13:10:10 CST (Thursday)
From   : Mike Meyer <mwm@Okc-Unix>
Subject: More on the MPM2 problem

The system walked on my mailbox, after I had seen that somebody had replied
to me on the MPM page zero problem, but before I read it. Since I couldn't
find the reply in the archives, I assume that it was addressed to me, and
not the list. Could whoever it was from please reply again.

While going through the archives, I noticed that somebody considered twisting
page zero and then complaining when it didn't workand DRI doesn't want to
help to be crass. I have a couple of comments:

       1) It wouldn't be so bad if they warned you about such things.
       2) They do fix page zero when it is page zero on a bank. I.e.,
               the code runs (correctly) in the first partition on each
               bank.
       3) This was CP/M software that somebody else wrote, and I was asked
               to move to MPM (don't ever let DRI fool you into thinking
               that those two are really compatable). DRI uses this trick
               for CP/M software themselves.
       4) I talked to the OEM who put wrote the BIOS. After looking at it
               (even thought it wasn't their problem), the decided that
               the BIOS never got control, and therefore the couldn't fix
               it. They told me not to other talking to DRI, as they had
               never been able to get a response from them.

On software compatability between MPM and CP/M. It does exist. As long as you
don't touch ANYTHING in the OS part of memory, don't do disk resets, and don't
do BIOS calls. I was
(unfortunately) stuck with moving a LOT of business software from MP/M to
CP/M. Like accounting stuff written in Microsoft BASIC. It broke at least
two of the three rules for CP/M software. Most screen oriented things will
also lose. I expect CP/M Plus to be more compatable with MP/M than with CP/M
2.2. *sigh*

       <mike