27 Oct
2006
27 Oct
'06
9:20 p.m.
Subject formerly: Re: Yet Another Old Cyber-Coot
On Sat, 2006-10-28 at 00:08 +0100, Tony Duell wrote:
I've always thought the analogy is between CP/M
and MSDOS (and not
because of the obvious technical similarities). Both are pretty minimal
OSes, both became industry standards, and in both cases there were often
better choices available.
[In the interests of avoiding problems, the following is a composite
of several coherent and consistent stories I got from several people who
were involved. This is how I understand events to have taken place,
and, therefore, constitutes my singular opinion of events as they
occurred. No claim of ultimate accuracy should be implied or assumed.
That should keep the wolves at bay...]
It's not at ALL surprising that MSDOS resembled CP/M. The first
version of MSDOS, called simply DOS, was actually a hot copy of CP/M for
8080 that had been run through a program, XLAT, (often called X-LAX by
those who had to clean up its output) that translated it from 8080 to
8086 mnemonics. It was produced by Seattle Computer Products (SCP) for
its combo 8080/8086 CPU board, from a commercial program of questionable
legality which "disassembled" the CP/M code running in your machine when
you ran it. (I forget the name. Anybody remember this?) It took the
crappy code (in this case code generated by the PL/M compiler, and made
commented assembly language source.
The folks at Seattle Computer Products got this disassembler, ran
it, took the output of that, and ran it into XLAT, and voila! CP/M for
the 8086. It was changed so that one could take the various
three-letter CP/M commands, and spell them out, and they would work.
Also, in an apparent attempt to avoid being sued by Digital Research,
they kept "ERASE" as an expanded command, but it only worked, in
abbreviated form, as "DEL". Apparently that was sufficient, as nobody
got sued. Bill Gates then bought out SCP -- I'm unclear if it was the
whole company or just the O/S product, and a legend was born. They went
to work, and started cleaning up their copy, and DOS for PC was born.
And, if not for a significant error by Gary Kildall, creator of CP/M, it
might well have been Digital Research Inc, in the place of MicroSoft.
What a different world we would live in, eh?
Peace,
Warren E. Wolfe
wizard at voyager.net