Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!zaphod.mps.ohio-state.edu!caen!news.cs.indiana.edu!msi.umn.edu!noc.MR.NET!nic.stolaf.edu!thor!mike From: mike@thor (Mike Haertel) Newsgroups: comp.arch Subject: Re: Moto 68451 (was Re: SunMMU history) Message-ID: <1991Jan27.053559.12345@acc.stolaf.edu> Date: 27 Jan 91 05:35:59 GMT References: <1991Jan19.133914.23871@bellcore.bellcore.com> <13875@encore.Encore.COM> <1991Jan23.154244.8322@motaus.sps.mot.com> <3149@crdos1.crd.ge.COM> Sender: news@acc.stolaf.edu Reply-To: mike@thor.acc.stolaf.edu () Organization: St. Olaf College; Northfield, MN Lines: 14 In article <3149@crdos1.crd.ge.COM> davidsen@crdos1.crd.ge.com (bill davidsen) writes: >In article <1991Jan23.154244.8322@motaus.sps.mot.com> skipper@motaus.sps.mot.com (Skipper Smith) writes: >| The 68451 was an MMU designed to be used with the 68010. It was a segmented > Was this the one used in the unix-pc/7300/3b1/safari box? Both of mine >have gone to new homes and I can't check easily. No, the 7300/3b1 uses an array of 1K words of fast static ram to hold the page table for 4 megabytes of memory. (4K pages) in order switch context you have to copy the new page table in and clobber any parts of the old that you didn't overwrite. this is rather like the early Sun MMU i guess, except that you don't have multiple contexts. -- Mike Haertel "He's a tie with the ambition to become a full-blown suit." -- Jon Westbrock