Path: utzoo!utgpu!water!watmath!clyde!bellcore!spectral!sjs
From: sjs@spectral.ctt.bellcore.com (Stan Switzer)
Newsgroups: comp.arch
Subject: Re: Is the Intel memory model safe from NO-ONE ?!?
Keywords: 386 intel memory protection management model segmented
Message-ID: <7282@bellcore.bellcore.com>
Date: 10 May 88 17:13:25 GMT
References: <1806@obiwan.mips.COM> <2904@omepd> <353@cf-cm.UUCP> <3384@drivax.UUCP>
Sender: news@bellcore.bellcore.com
Reply-To: sjs@spectral.UUCP (Stan Switzer)
Organization: Bellcore
Lines: 24

I agree with the consensus here that
 
  1) Segments can be a "Good Thing"
  2) but do not solve to the problem of not enough addressing bits
  3) and are not significantly superior to a partitioned (sparse,flat)
     addressing space
  4) and unless we can come up with a better model
  5) which Burroughs did rather nicely (in its day)
  6) and which is reflected, for instance, in the Smalltalk Virtual Machine
     (See also Pleasy/80(?), et al.)
  7) but which for lack of sufficient numbers of segments, is
     unimplementable with the '386 architecture (that is, making
     GOOD use of segments)
  7) and in any event will do little good in today's environments which
     are dominated by UNIX, MVS, VMS, and other systems which believe
     memory is (basically) flat.

So, I conclude that until we have languages and environments that can
make good use of segments (e.g. Smalltalk) and architectures that
support enough segments (shades of 432), flat's where it's at.

BTW, I LIKE segments, but you'll never find me programming a '286 or lower.

Stan Switzer sjs@ctt.bellcore.com bellcore!ctt!sjs