🚀 go-pugleaf

ts@cup.portal.com (Tim W Smith) writes:
> Ok, I give up.  Where did you get the idea that multitasking
> requires virtual memory?
> 
>					 Tim Smith
> ----------

Well, Tim, it doesn't REALLY, but VM sure makes it a hell of alot easier
to implement. With VM, as far as the processor is concerned, EVERY
process' Working Set is in memory, allocated to a different piece of a
very large virtual addressing space. When it comes time to process
switch, the dispatcher need not decide whether or not a process' WS is
actually in physical memory, it simply switches to the process and
allows the WS to page fault in with the VM handler if it isn't in
memory. Ask anyone who's tried to implement a clean multitasking system
without VM, and they'll tell you being strapped to a truck tire on a
cross country trip would be more fun.

Dave Waller
Hewlett-Packard Co.
Workstation Group
Pacific Technology Park
1266 Kifer Rd.
Sunnyvale, CA
(408) 746-5324
[ucbvax!]hplabs!hpdstma!dave | dave@hpdstma.ptp.hp.com
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