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From: johnl@iecc.cambridge.ma.us (John R. Levine)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: 8086 Unix, was Re: Comparing 486 to 386 Systems
Message-ID: <1991Apr10.035331.12694@iecc.cambridge.ma.us>
Date: 10 Apr 91 03:53:31 GMT
References: <1991Apr7.033635.18412@agate.berkeley.edu> <1991Apr9.150055.13705@cbfsb.att.com> <1991Apr9.234724.24830@agate.berkeley.edu>
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Organization: I.E.C.C.
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In article <1991Apr9.234724.24830@agate.berkeley.edu> c60b-1eq@e260-3e.berkeley.edu (Noam Mendelson) writes:
>UN*X can theoretically be run within the bounds of 640K, swapping processes
>to the hard disk (very, very often).

Ah, how soon they forget.  There were several perfectly OK versions of
Unix for the 8086.  IBM sold PC/IX, which was a pretty straight port of
Sys III as well as Xenix.  I worked on PC/IX and can testify that it was a
real no kidding Unix system running on an ordinary 640K PC/XT with a 10MB
disk.

Back in the Olden Days Unix ran on PDP-11s, and since the 8086 has
slightly more compact code than a PDP-11 and pretty much the same data
formats, anything that would fit in a split I/D process on a PDP-11 would
also fit in small model under PC/IX.  There were two big problems with
PC/IX -- the technical one was that it really was small model only (it
swapped and moved processes, adjusting segment registers as needed) and
the non-technical one was that IBM didn't promote it much and overpriced
it at $900.  But it was quite reliable, people reported that it'd stay up
for months at a time running canned applications with uucp in the
background.

And in most cases, it hardly swapped at all since 640K was enough for four
or five resident proceses along with the kernel.

Now, of course, I have 16MB of RAM and a 600MB disk on my 486 clone box,
and Sys V R3.2 fills up a lot of it.  Times change.
-- 
John R. Levine, IECC, POB 349, Cambridge MA 02238, +1 617 864 9650
johnl@iecc.cambridge.ma.us, {ima|spdcc|world}!iecc!johnl
Cheap oil is an oxymoron.