Altair 8800 name Was: Re: Altair 680 Expansion Boards?

Eric Smith spacewar at
Thu Dec 22 21:17:45 CST 2016

On Thu, Dec 22, 2016 at 7:01 PM, drlegendre . <drlegendre at> wrote:

> The Z80 also showed up in the Osborne, Kaypro and TRS-80 models.. mostly
> due to the fact that CP/M was written to it.

Use of the Z80 in the mainstream TRS-80 models (1 and III) had little or
nothing to do with CP/M.  The special CP/M with a non-standard TPA needed
for the Model 1 and III was just about useless, since it would only run
special TRS-80 versions of CP/M software. There were third-party mods for
the Model 1 and III to run a normal CP/M, but only a tiny fraction of
TRS-80 users did that.

CP/M may have been more of a factor for the Model II/12/16/6000, which
could run a normal CP/M without any hardware mods, as could the later Model
4 and 4P.  Most Model II family machines I saw in the wild were used to run
Radio Shack's accounting and business software on TRS-DOS II; few used
CP/M, possibly because there were much lower cost CP/M systems available
elsewhere.  Most Model 4 owners I knew didn't do any serious CP/M use on
it, and mostly used the 4 as an improved-spec III running TRS-DOS/LDOS/etc.

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