Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!cs.utexas.edu!tut.cis.ohio-state.edu!pt.cs.cmu.edu!andrew.cmu.edu!nl0s+ From: nl0s+@andrew.cmu.edu (Nathan James Loofbourrow) Newsgroups: comp.sys.mac.hardware Subject: Re: PMMU question Message-ID: Date: 18 Oct 89 20:53:22 GMT References: <8092@microsoft.UUCP> Distribution: usa Organization: Class of '92, Carnegie Mellon, Pittsburgh, PA Lines: 14 In-Reply-To: <8092@microsoft.UUCP> Brian Willoughby writes: > Just a quick question. If the optional PMMU chip for the Mac II is NOT > installed then how does the address bus get driven? I'm assuming that This question has an interesting answer (as opposed to all those questions with really dumb answers ;-) )... There's a doohickey known as the HMMU sitting in the PMMU slot of an pre-PMMU'd Mac II. The HMMU apparently followed the previous designs, the GMMU and the FMMU in reverse chronological order; thus its name, as the FMMU was the "Fake Memory Management Unit". Ask for trivia, get trivia. That's how I found this info out. Nathan