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From: daveh@cbmvax.cbm.UUCP (Dave Haynie)
Newsgroups: net.micro.mac
Subject: Re: Re: Multitasking Considered Useless?
Message-ID: <617@cbmvax.cbmvax.cbm.UUCP>
Date: Tue, 12-Aug-86 12:45:04 EDT
Article-I.D.: cbmvax.617
Posted: Tue Aug 12 12:45:04 1986
Date-Received: Thu, 14-Aug-86 05:47:15 EDT
References: <3150@ism780c.UUCP>
Organization: Commodore Technology, West Chester, PA
Lines: 46

> Keywords: CPU doesn't matter for multi-tasking
> 
>>No, the mac WASN'T designed for multi-tasking with stuff built into
>>the ROM for it like with the amiga, but the time for it is LONG overdue!
>>
> Oh come on!  The Mac has as much ROM support for multi-tasking
> as the Amiga :-)
> 

Really?  That's amazing!  The MAC ROM really has support for synchronization
of separately running tasks, task swapping, task prioritization, intertask 
signal and message passing, task based exception processing, etc.?  Then
why do they waste all of their comparatively limited ROM space (actually
Write-Protected RAM on the Amiga) with these routines if they don't intend
to use them.  Or are they used by the MAC OS but not accessable to the
user?  The Amiga starts up tasks for the Workbench, possibly a CLI, the 
mouse, the keyboard, the disk, the timer, etc. all as a part of normal
operation.  


> But seriously, the problem is not the Mac os.  It is the hardware.
> Apple was right to not try to put multi-tasking on the Mac.  Without
> an MMU, multi-tasking is dangerous.

It would be better stated that without an MMU, sloppy programming in a
multitasking environment is dangerous.  With the MMU, if I allocate a 1K
chunk of memory and then write to it as a 2K chunk, the hardware protects
it from being clobbered, whereas without the MMU I could stomp on memory
being used by another process or task.  But its still my error that's
causing the problem.  In a properly written program, I won't have the
ability to clobber the memory of another task.
> -- 
> "I *DO* believe in Mary Worth"
> 
> Tim Smith       USENET: sdcrdcf!ism780c!tim || ima!ism780!tim
> 		Compuserve: 72257,3706          Delphi || GEnie: mnementh
-- 
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Dave Haynie    {caip,ihnp4,allegra,seismo}!cbmvax!daveh

	"I gained nothing at all from Supreme Enlightenment, and
	 for that very reason it is called Supreme Enlightenment."
							-Gotama Buddha

	These opinions are my own, though for a small fee they be yours too.
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