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From: dillon@CORY.BERKELEY.EDU.UUCP
Newsgroups: comp.sys.mac
Subject: Re: Mac vs. Amiga (sorry)
Message-ID: <8701291953.AA04462@cory.Berkeley.EDU>
Date: Thu, 29-Jan-87 14:53:33 EST
Article-I.D.: cory.8701291953.AA04462
Posted: Thu Jan 29 14:53:33 1987
Date-Received: Fri, 30-Jan-87 06:18:02 EST
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: University of California at Berkeley
Lines: 27

>Just a quick question for you Amiga multi-taskers:
>
>How can you ensure safe multi-tasking with out an MMU?
>
>It would seem that any program could write abitrarily into any
>other program's memory - thus causing obvious problems.  Is there
>protection against such on the Amiga, or was the initial poster right
>in that the *program* must insure compatiblity with multi-tasking by
>asking the system for memory or something?
>
>Just curious,
>Stu

	Any program can write anywhere it wants... but I wouldn't advise it,
even on a Mac.  The Amiga has no MMU.  But then again, neither do many Xerox
machines and they multitask just fine.  The whole point is that properly
working programs don't go wandering off through memory.  In other words, you
can't ensure anything on an Amiga, or Mac, or Atari, or IBM, or any other
computer which doesn't put up firewalls between processes.

	So in answer to your question:  Compatibility has nothing to do with
it but YES, you must ask the system to allocate memory for you when you want
it.  Keep in mind though that memory allocation on an Amiga is extremely
optimized and extremely quick.  Also note that once you do allocate memory,
or create a custom screen etc... you can do whatever you want with it.

					-Matt