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From: kenk@tellabs.com (Ken Konecki)
Newsgroups: comp.sys.mac.system
Subject: Re: PPC, IAC, and True Multitasking (tm)
Message-ID: <3474@tellab5.tellabs.com>
Date: 21 Aug 90 12:19:14 GMT
References: <1990Aug3.040513.14844@d.cs.okstate.edu> <2760@bridge2.ESD.3Com.COM> <13888@cbmvax.commodore.com>
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In article <13888@cbmvax.commodore.com> valentin@cbmvax (Valentin Pepelea) writes:
>Actually, you either have pre-emptive multitasking, or you have nothing...
>An operating system has a pre-emptive scheduler, or it doesn't
>have one at all. There is no such thing as a cooperative scheduler. The term
>cooperative is used when there is an absence of a scheduler.

If I understand the point your trying to make, you're saying that in order
to be multitasking, an OS must provide a scheduler. Why must there be
a software scheduler? Under the multifinder implementation of
multitasking, the user is the scheduler. It's pretty much the same effect
as a software scheduler, but it makes no presumptions about what the user
intends. The user is the one responsible for assigning priorities to his/her
tasks and changing them as necessary. 


>If anything, a preemptive operating system will be faster, because it will
>perform task switching only when necessary.

Apparently you have never used a Sun. There have been countless times that
I have pushed ye olde mouse button and waited for *seconds* for the
wonderful preemptive OS to respond to the input. And I'm not the only
one making this complaint.

Cheers,
    -Ken K
--
Ken Konecki
"Eat well, stay fit, and die anyway"
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