Path: utzoo!attcan!uunet!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!hoptoad!tim
From: tim@hoptoad.uucp (Tim Maroney)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Need info on multitasking capabilities on the mac
Message-ID: <9071@hoptoad.uucp>
Date: 24 Nov 89 04:47:31 GMT
References: <9775@zodiac.ADS.COM> <39178@srcsip.UUCP> <36687@lanl.gov> <74117@tut.cis.ohio-state.edu> <36755@lanl.gov> <1209@radius.UUCP> <2008@atanasoff.cs.iastate.edu>
Reply-To: tim@hoptoad.UUCP (Tim Maroney)
Organization: Eclectic Software, San Francisco
Lines: 42

In article <2008@atanasoff.cs.iastate.edu> jwright@atanasoff.cs.iastate.edu
(Jim Wright) writes:
>OK, I'm sitting here with a 4 megabyte file to download.  *PERFECT* use
>for multi-tasking.  Thank god for multifinder.  Fire it up, start the
>download.  All's going well.  Leave.  Time passes.  Return.  Let's see
>how things are going.  Switch over to another program.  Browse around.
>Open up a menu from menu bar.  Hmmm... what do I want to do?  Look around
>for a bit.  Make a selection.  Check in on the download.  WHAT!!!!
>ABORTED!!!  Oh &^@$%^&%#@ great.  The entire computer comes to a screeching
>halt when you're in a menu.

This is just an implementation problem; it's not some kind of theoretical
limit to non-time-sliced multitasking.  Currently, some user interface
elements don't pass idle time to background applications when they should.
These include menu tracking and control tracking.  These are not intrinsic
problems with the idea of synchronous multi-tasking; Apple just didn't
realize that the routines Mouse and StillDown could be taken as implicit
signals allowing a context switch.  Hopefully, they will in future systems.

>I WANT REAL MULTITASKING.  Multifinder is better than MSDOS, but not much.
>
>Followup to alt.dev.null.  There's not much to do about this without a
>radical change to the Mac OS.

Wrong.  On the other hand, your point is not completely without merit.
If you start an upload and then go into StuffIt to extract information
from the file you just downloaded, StuffIt will refuse to give any time
to the rest of the system until it completes, and your upload will time
out.  This is more of a problem, and it *is* an intrinsic problem that
can only be solved with time-sliced multitasking.

So you are partially correct; there are in fact some things that really
do require time-slicing; but I think "not much better than MSDOS" is a
huge exaggeration.  And I've already dealt with the problems with
calling only time-slicing "real multitasking".
-- 
Tim Maroney, Mac Software Consultant, sun!hoptoad!tim, tim@toad.com

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