Path: utzoo!attcan!uunet!ncrlnk!ncr-sd!hp-sdd!hplabs!sm.unisys.com!csun!polyslo!dorourke
From: dorourke@polyslo.CalPoly.EDU (David M. O'Rourke)
Newsgroups: comp.sys.mac
Subject: 68030 MMU vs 68551 {was: Virtual Memory for the Mac II}
Summary: What are the differences??
Message-ID: <7136@polyslo.CalPoly.EDU>
Date: 18 Jan 89 23:27:44 GMT
References: <1250@cascade.Stanford.EDU> <35421@think.UUCP> <79271@felix.UUCP>
Reply-To: dorourke@polyslo.CalPoly.EDU (David M. O'Rourke)
Organization: Cal Poly State University -- San Luis Obispo
Lines: 22
Keywords:

In article <79271@felix.UUCP> kehr@felix.UUCP (Shirley Kehr) writes:
> different from that for the PMMU they are supplying for Mac II. She
> said that Apple only implemented a subset of the instruction set on
> the PMMU that comes with the 030 machines. (I barely know what I'm
> talking about; please forgive the vagueness)

  Not trying to flame you!!  The PMMU that's built into the 68030 is
just a subset of the 68551.  It's not Apple's fault, it's motorola's.

  Perhaps someone in the know would be nice enough to outline some of
the differences, and the ramifications of those differences, between
the 68030 the 68551.  I've always been curious about what the
differences are, but haven't had time to research them.  {Please no
flames, comments, ect about 68030 being a CPU and the 68551 being a
MMU, I know that much (not much more)}

  Thankyou in advance.
-- 
David M. O'Rourke                                  dorourke@polyslo.calpoly.edu

"If it doesn't do Windows, then it's not a computer!!!"
Disclaimer: I don't represent the school.  All opinions are mine!