Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!usenet.ins.cwru.edu!ncoast!davewt
From: davewt@NCoast.ORG (David Wright)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: How do we change the scheduler? (Was Re: Multitasking at home...)
Summary: More Shawn spew...
Message-ID: <1991Jan23.044023.4829@NCoast.ORG>
Date: 23 Jan 91 04:40:23 GMT
References: <1991Jan21.221744.5966@rice.edu> <1991Jan22.183746.27565@rice.edu> <1991Jan22.200035.29996@rice.edu>
Organization: North Coast Computer Resources (ncoast)
Lines: 45

In article <1991Jan22.200035.29996@rice.edu> jsd@arcadien.rice.edu (Shawn Joel Dube) writes:
>
>But the Amiga's tasking is still jerky.
	You obviously haven't seen it, or you saw it used be someone who
had their task priorities screwed up royally. The Amiga seems to do the best
task switching of any system I have used (Unix/Xenix/Minix, OS-9, Mac, NeXT,
Windows, etc.). Since by default all tasks run at the same priority,
tasks tend to not be jerky, but rather everything runs more slowly. Of course
the user is free to adjust the priorities to improve the time on more critical
tasks (which you can't do on the Mac). And even at a higher priority, most
tasks need to do something like wait for data from the [keyboard|mouse|serial]
device, and so give up the CPU during times when the user won't notice the
task switch.
>|> In any case, on
>|> the Amiga, no program can take exclusive control of the CPU unless it does
								^^^^^^^^^^^^^^
>|> something special, while on the Mac, an incorrectly written program can
^^^^^^^^^^^^^^^^^^^^^^
>|> easily do this, 
>
>I feel that that feature *should* exsist (program taking over complete control)
	Read what he said. He didn't say it was impossible (and almost all
commercial "arcade-type" programs do), he said that you had to specifically
ASK to do so, whereas on the Mac you must specifically ALLOW a task switch
(outside of system calls).
>the display might be distorted (slowed or jerky).  I have yet to encounter a Mac program
>that took full control.  In fact, old programs (written when the Mac was first released)
>work properly when used in MultiFinder.
	Hogwash. The older the Mac program is, the more likely it is to use
busy loops for timing (many games for the Mac won't run correctly on
faster machines. I know. Running them under AMax II on my 25Mhz 030 many
are unplayable because the programmer was to [lazy|stupid|ignorant] to
do timing via a hardware clock.) And under MultiFinder (which I use
exclusively when running AMax) many programs (not just games) hog the CPU
and the task in the front tends to get more CPU time than the others, which
may (and in my normal mode IS) be the incorrect thing to do.
	As another example of the brain-deadness of MultiFinder, consider
that you have to stop MultiFinder to make a system file change, then restart
all the applications you have running. This is rediculous. On the Amiga you
can change any system preference, and not only do things continue to operate,
but any program that wants to know about the changes can be automatically
notified, and start taking advantage of them right away.


				Dave