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From: milamber@caen.engin.umich.edu (Daryl Scott Cantrell)
Subject: Re: Amiga Custom Chips - why hasn't C= made them faster?
Message-ID: <1991Apr5.034303.14202@engin.umich.edu>
Sender: news@engin.umich.edu (CAEN Netnews)
Organization: University of Michigan Engineering, Ann Arbor
References: <1991Apr2.235710.13984@news.iastate.edu> <1991Apr3.201259.8377@engin.umich.edu> <1991Apr3.225433.16594@jato.jpl.nasa.gov>
Date: Fri, 5 Apr 1991 03:43:03 GMT

In article <1991Apr3.225433.16594@jato.jpl.nasa.gov> jdickson@jato.Jpl.Nasa.Gov (Jeff Dickson) writes:
>In article <1991Apr3.201259.8377@engin.umich.edu> milamber@caen.engin.umich.edu (Daryl Scott Cantrell) writes:
>>In article <1991Apr2.235710.13984@news.iastate.edu> xgr39@CCVAX.IASTATE.EDU writes:
>>
>>  What is the big deal about memory protection and resource tracking?
>>Sure, it might be a nice toy, but it wouldn't be real useful on a
>>single-user system.  Is this one of those things people want just
>>because Unix has it?
>>
>	I partially disagree. I could care-less about resource tracking, but 
>memory protection is important and not because UNIX has it. While the Amiga 
>may not be multiuser, it is multi-tasking and it is very disturbing to have the 
>entire machine go belly up due to a memory error induced by one task. In the 
>past, I thought it would be nice to have a BBS run concurrently while I did 
>development work, but the lack of memory protection doesn't warrant this. 
>
>	Yes, the Amiga is a single user machine and unfortunately it is
>single purpose for some of my purposes. I can only hope that one day, some-
>kind of memory protection is incorporated into the O.S. if an MMU is avail-
>able. I've heard the arguments against it, but nothing that hasn't already
>been done on costlier (had to put that in) systems. 
>
>			-jeff
>	

1) Memory protection isn't a whole lot of good without resource tracking.
Sure, you may keep this buggy program from dragging other stuff down with
it, but everything it was using when it dies is "gone".  You'll end up
having to reboot to get the stuff back anyways.

2) Are you sure you understand all the arguments against it?  The Amiga OS
has been shuffling pointers around between tasks for years now, making every
program out there behave for a memory protection scheme would be a ridiculous
amount of work.  It would be easier to simply go through and debug all those
programs we're trying to protect ourselves from.

3) There are a lot better things software people at CBM should worry about.
Virtual memory comes to mind as a far more productive use for the MMU.  Can
you say 100 MB free? [insert drool noise]  Not to mention color X-Windows
for Unix, etc., etc... All of which (ok, some of which anyway..) I'm sure
they're thinking-about/designing/coding/lying-to-us-about-not-having-yet at
this very moment.


--
+---------------------------------------+----------------------------+
|   // Daryl S. Cantrell                |   These opinions are       |
| |\\\ milamber@caen.engin.umich.edu    |    shared by all of    //  |
| |//  Evolution's over.  We won.       |        Humanity.     \X/   |
+---------------------------------------+----------------------------+
