[TUHS] Zilog Z80 Unix

Bakul Shah bakul at bitblocks.com
Thu Apr 20 14:34:10 AEST 2017

Yes, Cromemco was the company, Cromix their unix like OS.

IIRC, in 1981-83 timeframe someone I worked with had mentioned
he used to work at Cromemco and that they had a unix like OS
called Cromix. Cromemco were in Mountain View so likely they
were at the WCCF.

Even though z80 could only address 64k, their system had a
bank select under s/w control & upto 512K of RAM could be
added.  Z80 didn't have a supervisor mode but still, the bank
select must have  afforded enouh protection from bad pointers
crashing random processes.

On Wed, 19 Apr 2017 23:40:30 EDT Gregg Levine <gregg.drwho8 at gmail.com> wrote:
> Hello!
> That was also a board vendor. FYI: The first GASP [GetAway Special
> Program] a Space Shuttle payload made use of such a board.
> -----
> Gregg C Levine gregg.drwho8 at gmail.com
> "This signature fought the Time Wars, time and again."
> On Wed, Apr 19, 2017 at 11:09 PM, Bakul Shah <bakul at bitblocks.com> wrote:
> > On Wed, 19 Apr 2017 18:42:42 PDT "Erik E. Fair" <fair-tuhs at netbsd.org> wrote:
> >> I have a memory of having seen a Zilog Z-80 (not Z8002 like the Onyx) based 
> >> Unix, possibly v6, at a vendor show or conference - perhaps the West Coast
> >> Computer Faire (WCCF) in the late 1970s or early 1980s.
> >>
> >> I recall asking the people in the booth how they managed without an MMU, and
> >> don't recall their answer. I do remember thinking that since Unix had "grown
> >> up" with MMUs to stomp on obvious pointer mistakes, the software ought to be
> >> relatively well-behaved ... you know: not trying to play "core war" with 
> >> itself?
> >>
> >> I searched the TUHS archives cursorily with Google to see if this has been
> >> previously mentioned, but pretty much all Z80 CPU references have for its use
> >> in "smart" I/O devices back in the day.
> >>
> >> Does anyone else remember this Z80 Unix and who did it? Or maybe that it was
> >> a clone of some kind ... ?
> >>
> >>       looking for a little history,
> >>
> >>       Erik Fair
> >
> > You may be thinking of Cromemco.

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