Re: CompactMem from a CDA

[David A Lyons <dlyons@apple.com>]

In article <1tein9$k1l@apple.com> Matt Ackeret, unknown@apple.com writes:
> Yup, you're right!  That's a problem with multitasking on the GS.  If,
on
> the Mac, their memory manager compacts all heaps and not just the
current one,
> it'd be a problem there too. 

Mac heaps get compacted individually.

Even if they didn't, there is no problem with cooperative multitasking: 
Processes are switched out *only* when they call GetNextEvent or
WaitNextEvent, which are allowed to move memory.


> Having your memory moved out from under you is a scary prospect. Jawaid
has 
> said that it memory compaction doesn't happen very often on a 4 meg GS,
though
> it'd sure be nicer if the Memory Manager were able to compact by
userid..
> (though obviously it would make compacting memory a whole hell of a lot
less
> useful)

Compacting "by user ID" would not be useful, because there is *no*
restriction that a process can only access memory blocks that have
certain memory IDs.


David A. Lyons, Apple Computer, Inc.      |   DAL Systems
Apple II System Software Engineer         |   P.O. Box 875
Internet:dlyons@apple.com                 |   Cupertino, CA 95015-0875

My opinions are my own, not Apple's.