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From: hr@uicsl.UUCP
Newsgroups: net.micro.amiga
Subject: Re: Amiga MMU question
Message-ID: <151400006@uicsl>
Date: Thu, 7-Nov-85 10:50:00 EST
Article-I.D.: uicsl.151400006
Posted: Thu Nov  7 10:50:00 1985
Date-Received: Sun, 10-Nov-85 03:40:25 EST
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Nf-From: uicsl.UUCP!hr    Nov  7 09:50:00 1985


RE:
"> Multitasking does NOT require an MMU.  Processes are allocated separate
> places in memory, and then are timesliced..."

Actually, I have seen a TIMESHARING system that didn't have an MMU.
A couple of groups here had Alpha Micro systems. The processor was
the Western Digital "almost an LSI-11" chip set. The operating system
looked to the user a LOT like DEC's TOPS-10. PPN [1,2] was the system
account, for instance.

All the high level languages, like Lisp, generated position
independent code. They also checked to make sure that the users didn't
get outside of their areas. If you wrote in assembler, you could do
nasty things.

Since most of the users were doing word processing or simple programs,
and were friendly, the system seemed fairly stable.


A question for those who know. How much would a simple MMU have cost to
implement? Stride sells one for either $400 or $600 (I can't remember).
The Amiga was obviously designed to meet a specific price point. Why
else would they have made the 256KB an option? Our local dealer has
apparently not sold a single 256KB only system.


						harold ravlin
					{ihnp4,pur-ee}!uiucdcs!uicsl!hr