Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!killer!elg
From: elg@killer.Dallas.TX.US (Eric Green)
Newsgroups: comp.sys.amiga
Subject: Re: MMUs and Re: inconsistent gadget function parameter ordering
Message-ID: <7989@killer.Dallas.TX.US>
Date: 3 May 89 03:02:19 GMT
References: <23912@agate.BERKELEY.EDU>
Organization: The Unix(R) Connection, Dallas, Texas
Lines: 28

in article <23912@agate.BERKELEY.EDU>, c60c-1ea@web-1c.berkeley.edu (Yen Yuanchi Hsieh) says:
> MMUs on Amigas?  Somehow that seems farther into the future than the end of the
> year...
> 
> Unless this is Dave's new project?  :-)

No, Dave's old project. The A2620 (the 68020 card) has a MMU on it
(intended for running Unix, but can be used for other things too --
currently, he's using it to put Kickstart into 32-bit RAM to speed
things up tremendously). And all 68030 cards come with a MMU by
definition (the 68030 has one on-board). 

But don't expect miracles. As I said, the MMU was intended for running
Unix. As such, it's just fine for doing virtual memory, and if I had a
2620, I'd be working on hacking it this very moment (;-). But it was
not intended for AmigaDOS. AmigaDOS assumes one big shared address
space, with all the processes living in peace together in that big
shared address space. The MMU can make that big address space even
bigger. But it still can't keep process A from tromping on process B's
data, at least not without a big horrendous slow kludge.
     (But does the MMU support making pages execute-only? If so, at
least process A can be kept from tromping on process B's code).

--
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