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From: fish%calypso@Sun.COM (Lorenz Fish)
Newsgroups: comp.sys.amiga
Subject: Re: Memory Management
Message-ID: <34782@sun.uucp>
Date: Tue, 24-Nov-87 16:37:23 EST
Article-I.D.: sun.34782
Posted: Tue Nov 24 16:37:23 1987
Date-Received: Sat, 28-Nov-87 06:13:36 EST
References: <8711201906.AA25134@cory.Berkeley.EDU> <1406@atkins.munsell.UUCP>
Sender: news@sun.uucp
Reply-To: fish@sun.UUCP (Lorenz Fish)
Organization: Sun Microsystems, Mountain View
Lines: 41

I am posting this for Doug Merritt ({ucbvax,sun}!unisoft!certes!doug); I
will forward any replies for him:

In article <1406@atkins.munsell.UUCP> klm@atkins.UUCP (Kevin [Being Weird Isn't Enough] McBride) writes:
>In article <8711201906.AA25134@cory.Berkeley.EDU> dillon@CORY.BERKELEY.EDU (Matt Dillon) writes:
>
>>    As far as the Amiga goes, the only compatible solution is a Linear
>>virtual address space over the entire system.
>
>This seems like a perfectly rational and compatible way of doing VM on
>the Amiga. 

A nice idea, but unfortunately not perfectly compatible. As discussed
here some time ago, there's still the problem of, e.g. cooperating tasks
which have pointers into each others memory space. Message passing is
based on shared memory on the Amiga.

You could certainly rewrite such tasks to use a new method that allowed
for memory protection, but you could not have it work invisibly. I suppose
you could also just take the hit of such programs not working, but more
stuff would die than you might suppose. Cooperating tasks are a very nice
design paradigm on a machine like the Amiga; it would be a shame to give
them up...A big enough shame, in fact, that very few people would end
up adopting this solution.

But wait...maybe there's a bandaid? Perhaps you could rig up a way of
telling the system about tasks that need to share address space. Got
any ideas about this? Any such method would be inconvenient, but might
at least work.
	Doug Merritt		{ucbvax,sun}!unisoft!certes!doug
-------------------------------------------------------------------------

		 o   	Lorenz Fish	{ucbvax}!sun!fish@calypso
		 o
		 o @^_ 
		  <_~_>{
		    V

				Sun Microsystems	Mountain View, CA

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