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From: collinge@uvicctr.UUCP (Doug Collinge)
Newsgroups: net.micro.atari
Subject: Re:  Unix without an MMU
Message-ID: <162@uvicctr.UUCP>
Date: Sat, 11-Jan-86 16:21:26 EST
Article-I.D.: uvicctr.162
Posted: Sat Jan 11 16:21:26 1986
Date-Received: Tue, 14-Jan-86 05:21:59 EST
References: <8601071639.AA03270@ucbvax.berkeley.edu>
Reply-To: collinge@uvicctr.UUCP (Doug Collinge)
Organization: University of Victoria, Victoria B.C. Canada
Lines: 22

In article <8601071639.AA03270@ucbvax.berkeley.edu> dan@BBN-PROPHET.ARPA (Dan Franklin) writes:
>As an aside, the Sage IV 68000 system had no MMU, and did run Unix.  Or rather,
>it ran IDRIS, the Unix look-alike (which does have a Unix-style fork()).  I
>don't know which of the methods Mark listed they used, but I suspect the first
>one: running only one process at a time in memory, and swapping it out before
>starting another one.  

I have IDRIS. It does have fork(). It can run more than one process in memory
at once and usually does but after a fork it runs the parent and child in the
same space by swapping.  Of course, as soon as you do an exec (most of the time
right away) it gives you a new space and the swapping stops.  This is entirely
practical and works just fine.  I see no reason why a similar system couldn't
work on the ST - but it couldn't be SysV or 4.2 because some of the calls
require memory mapping, e.g. realloc().
-- 
		Doug Collinge
		School of Music, University of Victoria,
		PO Box 1700, Victoria, B.C.,
		Canada,  V8W 2Y2  
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