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Article #32964Re: Advantages of a 68030 and a IIx
From: gillies
Date: Wed, 05 Oct 1988 16:50
Date: Wed, 05 Oct 1988 16:50
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Maybe the 68030 in the Mac IIx benefits APPLE, not the customer - Perhaps Apple wanted to get a jump on Sun & NeXT, so they could claim "We have a 68030 machine". - The Apple MMU & Socket cost $$$ in manufacturing (there is a stub MMU in a regular Mac II without the 68851) -- this money can be saved in a 68030 machine. - There is only 1 configuration of IIx system board (no sockets), so board swaps are simpler, inventory is simplified (no 68851's to stock). Or, maybe it benefits A/UX customers - Is it true that 68030 $$$ <= 68020 $$$ + 68851 $$$ ? - The 68851 is a SLOW paging chip -- it adds 1 wait-state to A/UX memory references. Sun/etc. get around this with their own PMMU designs. Does the 68030 have this wait state? If not, then putting the 68030 in the IIx speeds up A/UX (but not the Mac O/S).
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arc1-ca.pugleaf.net!utzoo!attcan!uunet!husc6!think!ames!ncar!tank!uxc!uxc.cso.uiuc.edu!a.cs.uiuc.edu!p.cs.uiuc.edu!gilliesReferences:
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!husc6!think!ames!ncar!tank!uxc!uxc.cso.uiuc.edu!a.cs.uiuc.edu!p.cs.uiuc.edu!gillies From: gillies@p.cs.uiuc.edu Newsgroups: comp.sys.mac Subject: Re: Advantages of a 68030 and a IIx Message-ID: <76000295@p.cs.uiuc.edu> Date: 5 Oct 88 16:50:00 GMT References: <578@bruce.oz> Lines: 21 Nf-ID: #R:bruce.oz:578:p.cs.uiuc.edu:76000295:000:833 Nf-From: p.cs.uiuc.edu!gillies Oct 5 11:50:00 1988