From: jimwong@owlnet.rice.edu (Jim Wong)
Subject: Re: A-MaxII+ ?
Organization: Rice University
Date: Thu, 15 Oct 1992 22:45:07 GMT

In article <1992Oct15.205818.25427@rmece49.upr.clu.edu> raist@rmece02.upr.clu.edu (Ricardo Hernandez | 802-36-4453) writes:
>
>   Major BS.  When you have a cooperative multitasking OS, things do not
>run as "smoothly" as in a pre-emptive multitasking.  And from the programer
>point of view, it is a nightmare since his applications HAVE TO KNOW
>that they are in such environment and don't TAKE CONTROL over the
>execution of the system.  This is not like this in Preemptive.
>
>   Another thing is with priorities.  Preemptive multitasking will
>intercept the program properly, with cooperative you have to pray that
>the applications "behave properly" so that they comply with any 
>priority scheme.  Imagine you are writing a ray-tracer, and you as a
>programmer have to REMEMBER to pass control to the system.  BLAGH! 
>
>   This all translates to POOR PERFORMANCE and OVERHEAD.

Bzzt.  Wrong - control is automatically passed to the system when you ask
for the next event.  You can avoid giving time to background tasks if you
jump through a few hoops, but you have to do very little to ensure that
other applications get processing time.

[stuff about formattting floppies]
>
>    Answer NO.
Big deal.  I rarely use floppy disks anyway, and I don't mind taking a break
for a minute in the unlikely event that I need to format one.

>  What happens when you are donwloading through the modem on a Mac and
>try to access the disk drive at the same time?

It depends.  Generally, the drive goes on for a bit and the download
continues.  Ocassionally, I miss a packet and get an error.  No problem,
that's there are fancy protocols like zmodem.  Of course, downloading
while I use a floppy is harder generates more errors than using the hard disk,
but, like I said, I rarely use floppies.                                                                  

>
>  What happens when you are copying a file to disk and you write on 
>MS Word very fast (like I do)? - the copying temporarily stops
>
Why do you mean by "write on MS Word very fast"?  If you mean type very
quickly, then you're mistaken.  The copying process slows down, but does not
stop.  Look at it this way: for a keypress to get to Word, Word had to have
asked for that keypress from the system.  Every time Word asks for an event,
background processes get time.  By reducing the amount of time between
events, you slow down the amount of time available for other applications.
I'd imagine you could, in fact, almost stop a background copy by holding
down a random key, rapidly generating a large quantity of autokey events and
effectively shutting the Finder out of processor cycles.  Oh well.  Holding
down the 's' key doesn't seem like overly useful behavior to me.

>  So NO, it ain't better (cooperative vs preemptive).  If not, then why
>apple is taking steps towards preemptive?
>
Something appears to be wrong with your shift key; you've got capital letters
where they don't belong, and can't seem to capitalize those letters that should
be upper case.


-- 
Jim Wong (jimwong@owlnet.rice.edu)