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From: lsr@apple.UUCP (Larry Rosenstein)
Newsgroups: comp.sys.mac
Subject: Re: Mac Multitasking
Message-ID: <1544@apple.UUCP>
Date: Wed, 19-Aug-87 21:00:37 EDT
Article-I.D.: apple.1544
Posted: Wed Aug 19 21:00:37 1987
Date-Received: Sat, 22-Aug-87 07:22:29 EDT
References: <6565@eddie.MIT.EDU> <2742@hoptoad.uucp> <3638@cit-vax.Caltech.Edu> <2758@hoptoad.uucp> <496@rocky.STANFORD.EDU>
Reply-To: lsr@apple.UUCP (Larry Rosenstein)
Organization: Advanced Technology Group, Apple Computer
Lines: 43

In article <496@rocky.STANFORD.EDU> ali@rocky.UUCP (Ali Ozer) writes:
>
>I did not need to "change a few lines in my code," nor I did not need to
>decide before had that I was going to run VT100 during VideoScape.

It turns out that some existing programs will run without change in the
background under Multifinder.  There are programs that were written to
allow user interaction (menus choices, etc.) while it is off computing.
The most common way of doing this is to poll for events while processing
and handle the event normally when one comes in.

Multifinder will do a process switch at these times.  All that is necessary
is that Multifinder be told that the application can run in the background,
which is indicated by a bit in a resource.  (The Multifinder people tried
this with one public domain program and it worked fine.)

>I appreciate Apple's effort in trying to get the Mac to multitask --- what
>I don't understand is how they call these current attempts (like the
>Switcher and now the Multifinder) "multitasking". 

You can say that the multitasking in Unix or the Amiga O/S is more
advanced, but you cannot say that Multifinder is not multitasking.
Multitasking is the ability to run 2 processes (apparently) at the same
time, which is something Multifinder can do.

It is true that Multifinder 1.0 uses non-preemptive scheduling as opposed
to preemptive scheduling used by the Amiga or Unix.  This means that
applications have to be cooperative in order to run in the background.

From the end user's point of view, the result is the same; you can have
your computer do more than one thing at a time.  The vast majority of users
could care less how it works inside.  The difference between Multifinder and
the Amiga O/S is subtle and something that many users won't understand.

-- 
Larry Rosenstein

Object Specialist
Apple Computer

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