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From: jesup@cbmvax.commodore.com (Randell Jesup)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Help --> How to prevent the visit from the dreaded guru
Keywords: Exec, Messages, Protected memory, MMU, Hunks, Caffeine.
Message-ID: <17135@cbmvax.commodore.com>
Date: 6 Jan 91 00:47:06 GMT
References: <611@caslon.cs.arizona.edu> <1991Jan4.224833.24914@ncsuvx.ncsu.edu> <17130@cbmvax.commodore.com> <1991Jan5.213642.16547@isis.cs.du.edu>
Reply-To: jesup@cbmvax.commodore.com (Randell Jesup)
Organization: Commodore, West Chester, PA
Lines: 38

In article <1991Jan5.213642.16547@isis.cs.du.edu> chanson@isis.UUCP (Chris Hanson) writes:
>  Couldn't you just make all inter-process communication be done using
>MEMF_PUBLIC memory? As it was supposed to be? Since most people didn't do
>this, Maybe make all the Message functions automagically force the
>exchanged memory to be MEMF_PUBLIC temporarily. It'd be a pain, and a
>megakludge, but it might work.

	Won't work.  A message usually has pointers to other areas of
arbitrary memory, or has an extended structure (ala StandardPacket), etc, etc.
As has been discussed before, MEMF_PUBLIC can't be used since each person
has had a different idea as to what should be public and what shouldn't.

>  As for Bill Gates: Did anyone else notice the InfoWorld Christmas-list
>column, wherein they suggested that he wants a Video Toaster for Christmas,
>to produce his next "IBM/Microsoft invented/is-leading-the-market-in
>multimedia" video?

	:-)

>  Agreed, adding protection might break large quantities of stuff. How
>about some kind of retrofit? Create a new object file hunk, say HUNK_FLAGS,
>which tells you intimate info about the program that LoadSeg is bringing in.
>You could have a flag to signify "I'm a nice program and I work well under
>memory protection, so protect me if you can". This would also be an
>excellent place to finally settle the PURE code problem. Make a hunk flag
>that signifies, regardless of what the FS bit says, "This code is pure,
>damnit." ;)

	A better idea.  You _could_ allow segments of code from a loadfile
to be protected (at least without many problems), and you could allow 
applications to request protected memory.

-- 
Randell Jesup, Keeper of AmigaDos, Commodore Engineering.
{uunet|rutgers}!cbmvax!jesup, jesup@cbmvax.commodore.com  BIX: rjesup  
The compiler runs
Like a swift-flowing river
I wait in silence.  (From "The Zen of Programming")  ;-)