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From: charles@hpcvca.CV.HP.COM (Charles Brown)
Newsgroups: comp.sys.amiga
Subject: Re: Memory protection for all amiga's
Message-ID: <5660071@hpcvca.CV.HP.COM>
Date: 21 Mar 90 22:42:40 GMT
References: <227.25ff6050@waikato.ac.nz>
Organization: Hewlett-Packard Co., Corvallis, Oregon
Lines: 23

> The problem with that is that you could no longer multitask well. 
> Communication between processes on the Amiga is accomplished by one
> process passing a message pointer to another process.  Only a pointer
> is passed, not the entire message.  This means that the tasks in
> question must share the same address space.  An MMU would prohibit
> that.  An MMU causes each process to run in its own
> "aritifically-induced" address space, so a pointer from one process
> will not point to the same address as the same value of that pointer
> for another process.
> -- 
>      ///  Alex Matulich

This is not quite true.  The process which will pass a message must
first allocate the message space from the global pool.  This would be
a pool of memory which is set aside for all shared memory requirements
such as message passing.

All memory which was not allocated from the global pool would be
protected. 
--
	Charles Brown	charles@cv.hp.com or charles%hpcvca@hplabs.hp.com
			or hplabs!hpcvca!charles or "Hey you!"
	Not representing my employer.