Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!batcomputer!mha
From: mha@batcomputer.tn.cornell.edu (Mark H. Anbinder)
Newsgroups: comp.sys.mac
Subject: Re: Apple's Pricing, IIx question
Message-ID: <7562@batcomputer.tn.cornell.edu>
Date: 16 Mar 89 19:39:19 GMT
References: <919@fornax.UUCP> <468@lakesys.UUCP>
Reply-To: mha@tcgould.tn.cornell.edu (Mark H. Anbinder)
Distribution: na
Organization: Department of Media Services, Cornell University, Ithaca NY
Lines: 21

In article <468@lakesys.UUCP> macak@lakesys.UUCP (James Macak) writes:
>
>The standard Mac II does not come with a PMMU chip.  There is certainly an
>empty space on the board to accept such a chip, but it _is_ an empty space on
>the "regular" Mac II.  (Little wonder you find it to be "nonfunctional!" :-)
>
>Jim

Actually, the Mac II comes with an MMU chip referred to, I believe, as an
AMMU.  This chip sits in the same place where the PMMU would be installed,
so there isn't any empty space.  As I understand it, the AMMU isn't
ENTIRELY nonfunctional... it sits there trapping memory management calls
and returning a "page fault" error for all of them.  The 68851 PMMU is
needed for any real memory management.


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Mark H. Anbinder                                ** MHA@TCGould.tn.cornell.edu
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