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From: dant@ryptyde.UUCP (Daniel Tracy)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: Amiga basher
Message-ID: <60@ryptyde.UUCP>
Date: 17 Jun 91 13:06:20 GMT
References: <1991Jun13.065150.3529@cs.mcgill.ca> <1991Jun14.033035.21572@daimi.aau.dk> <56@ryptyde.UUCP> <1991Jun16.152251.17044@cunixf.cc.columbia.edu>
Reply-To: dant@ryptyde.UUCP (Daniel Tracy)
Organization: Ryptyde Timesharing (ryptyde.cts.com)
Lines: 21

Responding to the following:

"       Macintosh multitasking requires the programmer to write
their code in a very specific way. Additionally, the task you are
interacting with gets the vast majority of time, even if it
doesn't need it. Which needs the time more: Tetris or the compile
job that is running in the background?"

First off, nearly all applications written before Multifinder multitasked
in it, and you DON"T have to "write your code in a very specific way".
Anything that involves user interaction calls WaitNextEvent(), which does
tell the OS that the app is waiting for user input and you should switch
to the next app. WaitNextEvent() is called all the time, not just when
apps are waiting for user input, because they always have to take user
input into account. For example, during a lengthy operation, an application
has to check to see if the user has clicked on the Cancel button. I KNOW
Macintosh multitasking isn't pre-emptive and isn't priority-based, but
it's there and available from all applications, although some (Hypercard,
Stuffit Classic) take up a lot of processing power. And yes, foreground
applications take up about twice as much processing power as background
(I tested this), but that's cooperative multitasking for you.