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From: guido@mcvax.UUCP (Guido van Rossum)
Newsgroups: net.micro
Subject: Re:  The 68010 and MMU's
Message-ID: <5912@mcvax.UUCP>
Date: Wed, 25-Jul-84 08:19:27 EDT
Article-I.D.: mcvax.5912
Posted: Wed Jul 25 08:19:27 1984
Date-Received: Sat, 28-Jul-84 10:04:21 EDT
References: <1999@sri-arpa.UUCP> <3@rlgvax.UUCP> <134@apple.UUCP>
Reply-To: guido@mcvax.UUCP (Guido van Rossum)
Organization: "Stamp Out BASIC" Committee, CWI, Amsterdam
Lines: 14

>The apple Lisa uses a plain 68000 and *does* squeeze blood out of the stone.
>Memory is segmented and code is demand loaded. The trick is that *some*
>instructions are restartable. There is much magic and kludges involved.

A very early UNIX implementation on a 68000 by ACE in the Netherlands
did the same.  Essentially, the compiler generated such a restartable
instruction at the beginning of each C procedure which tried to reach to
maximum needed stack address.  The memory fault this could cause was handled
by the kernel, and the program restarted.
I guess the Bourne shell caused them the most problems.

--
	Guido van Rossum, "Stamp Out BASIC" Committee, CWI, Amsterdam
	guido @ mcvax