Path: 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: <19553@uflorida.cis.ufl.EDU> <246@taniwha.UUCP> <6051@hoptoad.uucp> Organization: Apple Computer Inc, Cupertino, CA Lines: 16 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