Subject: Re: Xah Lee's Unixism
From: rpw3@rpw3.org (Rob Warnock)
Date: Thu, 02 Sep 2004 23:06:52 -0500
Newsgroups: comp.lang.perl.misc,alt.folklore.computers,comp.lang.lisp,comp.lang.python,comp.unix.programmer
Message-ID: <IpWdndgNVutBcKrcRVn-gg@speakeasy.net>
Rupert Pigott  <roo@try-removing-this.darkboong.demon.co.uk> wrote:
+---------------
| Pascal Bourguignon wrote:
| > In anycase, at the time the Macintosh appeared, there were
| > already 680x0 based unix workstations.
|
| It was specifically the 68000. Fixes were made that took effect in the
| 68010 and 68020. Dunno about 68008. IIRC the problem was that you could
| not restart some instructions properly. Some UNIX workstations did use
| 68Ks, there was an Apollo that had two of them running in lock-step,
| with one of them one instruction behind the other. When the leading CPU
| barfed, action would be taken and the other CPU would take over. Someone
| in comp.arch worked on the Fortune boxes and IIRC he claimed they had a
| more elegant single CPU solution.
+---------------

That would have been me, in <news:R4OdnfWrcMv1ekHdRVn_iw@speakeasy.net>,
replying to John Mashey. We tweaked the C compiler's calling conventions
enough to allow automatic stack growth by faulting off the end of the
stack to work reliably. See the referenced article for more detail.

But as I finished there:

    Though there were certainly other places where the mc68000's imprecise
    exceptions left no choice but to blow the offending process away...


-Rob

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