Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!oliveb!pyramid!ctnews!mitisft!jay
From: jay@mitisft.Convergent.COM (Jay O'Conor)
Newsgroups: comp.sys.mac
Subject: Re: Apple System 7.0
Summary: preemptive vs. cooperative MultiFinder scheduling
Message-ID: <705@mitisft.Convergent.COM>
Date: 30 May 89 16:20:39 GMT
References: <17183@usc.edu> <4679@okstate.UUCP> <1925@internal.Apple.COM> <2097@ccnysci.UUCP>
Organization: Convergent Technologies, San Jose, CA
Lines: 43


In-reply-to: your article <2097@ccnysci.UUCP>
News-Path: ctnews!pyramid!decwrl!shelby!rutgers!cmcl2!ccnysci!alexis

> In article <9344@polya.Stanford.EDU> shap@polya.Stanford.EDU
> (Jonathan S. Shapiro) writes:
> >The mac isn't fast enough for me to care whether multitasking is
> >preemptive or not.
> 
> That's not too clever. A Mac running A/UX 1.1 looks pretty competitive with
> a Sun 3/60. Don't tell me it would look just as good with non-preemptive
> multitasking (even if the concept weren't ridiculous in a Unix context...).
> 
> In fact, for all the non-optimal hardware design, the Mac isn't particularly
> slow. It's just that CPU gets used in a markedly different way than on most
> other machines. Which is not to say that I wouldn't prefer preemptive multi-
> tasking myself.
> 
> Waiting for 8.0 :-)
> ---
> Alexis Rosen
> alexis@ccnysci.{uucp,bitnet}
> alexis@rascal.ics.utexas.edu  (last resort)

Given a choice between having preemptive multitasking, and hardware/system
changes to allow more background time in a cooperative multitasking 
environment, give me the better support for cooperative multitasking!
Gimme DMA and a graphics coprocessor!!!  Cooperative scheduling can work VERY
well as long as the apps do just that - cooperate.  Today, as it stands, 
GetNextEvent/WaitNextEvent just doesn't hack it.  I'd like to see the system
be able to take advantage of disk and display I/O time for background 
processes.  I'd also like to see developers come out with new versions of
their programs that provide better support for MultiFinder.  Sorry, just 
because an app has a SIZE -1 resource and uses WaitNextEvent doesn't mean it
has good MultiFinder support.  As an example, compare background downloading
between VersaTerm (version 3.02, I think) and Compuserve Navigator.  As much
as I like VersaTerm, Navigator does a much better job of background 
downloading.

After working 10 years for a company with a proprietary cooperative 
multitasking OS, I just had to jump into this discussion!

Jay O'Conor