Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!thunder.mcrcim.mcgill.edu!snorkelwacker.mit.edu!usc!cs.utexas.edu!oakhill!motaus!skipper From: skipper@motaus.sps.mot.com (Skipper Smith) Newsgroups: comp.arch Subject: Re: Moto 68451 (was Re: SunMMU history) Message-ID: <1991Jan23.154244.8322@motaus.sps.mot.com> Date: 23 Jan 91 15:42:44 GMT References: <1991Jan19.133914.23871@bellcore.bellcore.com> <13875@encore.Encore.COM> Organization: Motorola Semiconductor, Austin, Texas Lines: 25 In article <13875@encore.Encore.COM> jcallen@encore.Com (Jerry Callen) writes: >In article pcg@cs.aber.ac.uk (Piercarlo Grandi) writes: >>The 68451 was not that long coming, and could be used as a TLB. Yes, it >>was slow. > >Hmmm, what _is_ this part? I see from my Arrow catalog that I can order one, >and it's described as an MMU, but my M68000 Family Reference never mentions it. >Is it an early version of the 68851? > >-- Jerry Callen > jcallen@encore.com The 68451 was an MMU designed to be used with the 68010. It was a segmented MMU, real slow, and has generally been surpassed in every category (performance, speed, capability, etc...) by the 68851 and the MMU built into the 68030. I highly doubt that Arrow actually has any parts in stock (since it is a part which Motorola doesn't recommend for new designs), but they might just have a couple of them lying around somewhere. Another place to check would be with Krueger Electronics (a used part house somewhere in New Jersey, I think). -- Skipper Smith | skipper@motaus.sps.mot.com Motorola Technical Training | 8945 Guilford Rd Ste 145 All opinions are my own, not my employers | Columbia, MD 21046