Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!amdcad!sun!hanami!landman
From: landman%hanami@Sun.COM (Howard A. Landman)
Newsgroups: comp.sys.mac
Subject: Re: When will MacOS get virtual memory?
Message-ID: <72647@sun.uucp>
Date: 12 Oct 88 19:16:26 GMT
References: <5624@zodiac.UUCP> <76000290@p.cs.uiuc.edu> <39513@yale-celray.yale.UUCP>
Sender: news@sun.uucp
Reply-To: landman@sun.UUCP (Howard A. Landman)
Organization: Sun Microsystems, Mountain View
Lines: 25

>In article <76000290@p.cs.uiuc.edu> gillies@p.cs.uiuc.edu writes:
>>cannot support virtual memory.  This is because the 68000 chip has a
>>design flaw that doesn't allow virtual memory to be implemented.

In article <39513@yale-celray.yale.UUCP> jellinghaus-robert@yale.UUCP writes:
>Someone really should tell Sun or Apollo.  They've produced many workstations
>with 68000's running UNIX, which DOES support virtual memory and page swapping.
>Gosh, wonder how they do it?

I can't speak for Sun or Apollo (what? I work at Sun!), but when I was at
Metheus we did it too.  It took *2* 68000s.  I suppose a big wad of external
logic would also work.  Either way, the problem is COST!

>Virtual memory doesn't REQUIRE hardware memory management.  It's a lot easier
>if you have the PMMU, but it's not impossible to do on a 68000.

Computer users don't REQUIRE price/performance either.  Perhaps I could
interest you in a TRS-80 Model I ?   Although, it actually draws characters
on its screen faster than a Mac does.  Hardware character generation isn't
REQUIRED, but it sure speeds things up!  (Of course, you lose some flexibility
there ... :-)

	Howard A. Landman
	landman@hanami.sun.com
	UUCP: sun!hanami!landman