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From: charles@tasis.utas.oz.au@munnari.oz (Charles Lakos)
Newsgroups: aus.mac,comp.sys.mac.programmer
Subject: Multifinder memory management?
Message-ID: <1039@diemen.cc.utas.oz>
Date: 16 Sep 89 02:50:37 GMT
Sender: root@diemen.cc.utas.oz
Lines: 31

I would like to know a bit more about Multifinder memory management.  The
specific situation concerns a DRVR which is permanently resident (once
installed) which requests activation once every 60th of a second.
(For information, it is a screen saver cum general timing utility.)
The recent Tech note (#248) on the subject points out that with Multifinder
active, the current heap zone may not be the one you expect.  That's OK.

The DRVR allocates a couple of small blocks of memory (for regions) but
tries to clean up on exit by compacting the memory every now and then.
With Finder this works marvellously - the DRVR cleans up the machine's
memory while it is idle.  With MultiFinder, it seems to suffer heap
fragmentation, so that after a day's operation, it may not be able to find
1 meg of memory on a 5 meg mac II.

So what is to be done?  Is this an inevitable consequence of MultiFinder 
switching in the DRVR so frequently?  Is there a better way of ensuring that
a couple of small blocks allocated frequently (and deallocated) do not
result in heap fragmentation?

Charles Lakos.

IP: 	charles@tasis.utas.oz.au
Snail:  Computer Science Dept., University of Tasmania,
	GPO Box 252C, Hobart, TAS, 7001, Australia.
Charles Lakos.

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Snail:  Computer Science Dept., University of Tasmania,
	GPO Box 252C, Hobart, TAS, 7001, Australia.