Re: 4 Meg simms

Article View: comp.sys.mac

Article #35462

#35462

From: David Goldsmith
Date: Wed, 14 Dec 1988 19:48

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In article <6051@hoptoad.uucp> tim@hoptoad.UUCP (Tim Maroney) writes:
>A lot of people have mentioned that the Mac II OS can't cope with more
>than 8 megabytes of RAM -- here's why.  The ROM starts at the 8 meg
>mark.  I guess A/UX gets around this by using the PMMU to remap it.
>This implies that the Mac OS won't be able to cope until it has PMMU
>support (which will be a great day for us developers), and of course
>you'll need to buy a 68851 to have more than 8 megabytes.

Actually, the ROM is mapped at 8 MB only in 24 bit mode.  In 32 bit mode,
the ROM is mapped at $40800000.  When the Mac OS runs in 32 bit mode you'll
be able to have more than 8 MB of memory even if you don't have a PMMU
or 68030.
-- 
David Goldsmith                                           Apple Computer, Inc.
AppleLink: GOLDSMITH1    BIX: dgoldsmith         20525 Mariani Avenue, MS: 46B
UUCP: {nsc,dual,sun,voder,ucbvax!mtxinu}!apple!dgold       Cupertino, CA 95014
CSNET: dgold@apple.com

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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!lll-winken!lll-tis!ames!mailrus!husc6!bloom-beacon!apple!dgold

References: <EXc49-y00UgXM0wn93@andrew.cmu.edu> <19553@uflorida.cis.ufl.EDU> <246@taniwha.UUCP> <6051@hoptoad.uucp>

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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!lll-winken!lll-tis!ames!mailrus!husc6!bloom-beacon!apple!dgold
From: dgold@Apple.COM (David Goldsmith)
Newsgroups: comp.sys.mac
Subject: Re: 4 Meg simms
Message-ID: <316@internal.Apple.COM>
Date: 14 Dec 88 19:48:35 GMT
References: <EXc49-y00UgXM0wn93@andrew.cmu.edu> <19553@uflorida.cis.ufl.EDU> <246@taniwha.UUCP> <6051@hoptoad.uucp>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 16

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