Path: utzoo!mnetor!uunet!husc6!cmcl2!nrl-cmf!ames!claris!apple!lsr
From: lsr@Apple.COM (Larry Rosenstein)
Newsgroups: comp.sys.mac
Subject: Re: Preemptive and Nonpreemptive Multitasking
Message-ID: <7769@apple.Apple.Com>
Date: 24 Mar 88 19:01:32 GMT
References: <4129@hoptoad.uucp> <283@rhesus.primate.wisc.edu> <1710@ssc-vax.UUCP> <234@cf-cm.UUCP>
Organization: Advanced Technology Group, Apple Computer
Lines: 29

In article <234@cf-cm.UUCP>, ralph@computing-maths.cardiff.ac.uk (Ralph Martin) writes:
>
> A second thing the OS does is to handle memory management. On the mac, the
>poor programmer has to worry about handles, and relocation blowing him
>away.

Handles on the Macintosh are optional (although very useful).  You can
allocate nonrelocatable blocks if you want, and you can lock handles to
prevent them from moving.  Memory is compacted only when needed, and the
times when this happens are well-documented.

On a machine without an MMU, it would be hard to support highly interactive
applications without a compacting memory manager.

>sun, but I LOATHE programming it. On the sun, part of the OS (the notifier)
>takes care of events and calls the bits of code I want in response to the
>events. On the Mac, I have to ask all the time what is going on, figure out

This is the application model used by MacApp.  MacApp goes beyond handling
user events (eg, moving windows).  MacApp will handle moving & resizing
windows without the programmer having to write any code.  But MacApp also
takes care of printing, file management, memory management, error handling
issues.

-- 
		 Larry Rosenstein,  Object Specialist
 Apple Computer, Inc.  20525 Mariani Ave, MS 32E  Cupertino, CA 95014
	    AppleLink:Rosenstein1    domain:lsr@Apple.COM
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