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From: djohnson@beowulf.ucsd.edu (Darin Johnson)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: How do we change the scheduler? (Was Re: Multitasking at home...)
Message-ID: <16176@sdcc6.ucsd.edu>
Date: 30 Jan 91 19:01:29 GMT
References: <7553@sugar.hackercorp.com> <1991Jan27.214435.15976@Neon.Stanford.EDU> <7664@sugar.hackercorp.com>
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In article <7664@sugar.hackercorp.com> peter@sugar.hackercorp.com (Peter da Silva) writes:
>In article <1991Jan27.214435.15976@Neon.Stanford.EDU>, torrie@cs.stanford.edu (Evan J Torrie) writes:
>>   Has anyone thought about adding VM/protection onto AmigaDos??  Is it
>> going to be a problem?  
>
>Yes, and yes.

OK, here's an idea.  Since a lot of the problems will result because some
programs may not use MEMF_PUBLIC correctly, why not have a utility that
allows only specified programs to run with VM/protection.  For example:

  > runvm mytestprog
  -= Illegal Address Format @xxxxxx =-
  -= Terminating process =-
  -= We now return you to your regularly scheduled(ha) system =-

  >runvms swap=hd0:swap mytestprog2
  -= Sorry, process attempted to send a message using private memory =-

etc.

I think this would simplify the task of trying to get VM to work
with everything under the sun.  What would be needed is a paging handler and
setpatching of memory routines.  If you want more than one VM task to run
at once, or to work with other mmu utilities, then you have to make sure
that the scheduler correctly switches context in the mmu when necessary.
-- 
Darin Johnson
djohnson@ucsd.edu
  - Political correctness is Turing undecidable.