"CP/M compatible" vs. "MS-DOS Compatible" machines?
Roy J. Tellason
rtellason at verizon.net
Sat Feb 2 16:47:15 CST 2008
On Tuesday 29 January 2008 16:33, Joshua Alexander Dersch wrote:
> scheefj at netscape.net writes:
> > In the early-mid 80's a program was "well behaved" if it did it's I/O
> > thru DOS calls. Those programs would run on just about anything.
> Were there similar problems in the CP/M world? That is, was it commonplace
> for there to be CP/M programs that bypassed CP/M BDOS calls and wrote
> directly to a specific machine's hardware? Seems like CP/M developers were
> more disciplined in this fashion, but maybe it's just because in the CP/M
> arena there were so many different pieces of hardware it was the only way
> to do it? (Whereas with IBM, the PC was seen as more of a reference
> standard, even if it wasn't really that way in the beginning?)
> I'd be interested to hear opinions from people who were there at the time,
> since it was a little before my time.
There was stuff written for specific hardware (floppy formatting code for one
fairly typical example), and then there was stuff that got patched for a
specific machine, which more often tended to address things like video
attributes and similar stuff -- I know that the copy of WordStar I used to
use on my Osborne Exec was patched all to hell. :-)
So was the directory listing program I used, "sd".
Other code that often needed to be modified for specific hardware or machines
were comm stuff, which more often seemed to have a bunch of "overlays"
available for each machine, so that things could address the serial port (or
the PMMI S-100 bus modem) properly.
I probably have piles of this stuff in my old bbs files area, if there's much
interest in it.
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ablest -- form of life in this section of space, a critter that can
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