Path: utzoo!attcan!uunet!isc-br!jimc
From: jimc@isc-br.ISC-BR.COM (Jim Cathey)
Newsgroups: sci.electronics
Subject: Re: 1802 et al.
Message-ID: <2732@isc-br.ISC-BR.COM>
Date: 1 Feb 90 19:18:38 GMT
References: <3218@uceng.UC.EDU> <914@xroads.UUCP> <1874@neoucom.UUCP> <78519@psuecl.bitnet> <138@macuni.mqcc.mq.oz> <13506@cit-vax.Caltech.Edu> <156@macuni.mqcc.mq.oz> <761@nixpbe.UUCP>
Organization: ISC-Bunker Ramo, An Olivetti Company
Lines: 29

In article <761@nixpbe.UUCP> josef@peun11.uucp (Moellers) writes:
>I agree, nobody with a grain of sense would design a multi-user
>UNIX-machine with e.g. an Z80 but to use a 32532 as a controller in an
>8pin matrix printer would be overkill!

Interestingly, the Morrow Decision 1 computer (S-100 Z-80A based) of a few
years ago ran Micronix, a port of Unix version 7.  It actually worked!  My
roommate had one.  With 1 user it wasn't too bad, but more than one loaded
it pretty good.  He didn't have enough memory for it.  It was a segment
swapping OS, not demand paged virtual.  The CPU card had a hardware MMU
that mapped 4K pages and added protection to accomplish the magic.  They
had a CP/M emulator that ran under Micronix so you could run WordStar et. al.
from the shell.

Boy, I'd never want to have to design one of these puppies!  As a Unix
engine, though, it was better than Coherent for PC's -- the MMU offered
intertask protection which Coherent didn't have.  The MD1 was
crash-proof, but the PC was better for C programming as it had 16-bit
ops.  

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