Path: utzoo!attcan!uunet!cs.utexas.edu!rutgers!uwvax!tank!uxc!uxc.cso.uiuc.edu!ux1.cso.uiuc.edu!uxe.cso.uiuc.edu!mcdonald
From: mcdonald@uxe.cso.uiuc.edu
Newsgroups: comp.sys.mac
Subject: Re: Re: Re: Apple System 7.0, Amiga
Message-ID: <46100305@uxe.cso.uiuc.edu>
Date: 31 May 89 18:07:00 GMT
References: <3269@uokmax.UUCP>
Lines: 32
Nf-ID: #R:uokmax.UUCP:3269:uxe.cso.uiuc.edu:46100305:000:1407
Nf-From: uxe.cso.uiuc.edu!mcdonald    May 31 13:07:00 1989


Subject is multitasking:

>So what is it that everyone seems to want?  Beats the **** out of me.  What
>is it that everyone seems to need?  Well, I've been wrong before (twice 
>already this year :-), but IMHO, we need well written programs that 
>understand the concept of how MacOS works.  (And IPC, and email, and
>virtual memory, and protected memory, and ...)

What people want in multitasking is real multitasking. That means that 
one task hogs the system resources IF AND OMLY IF the user (we are referring
here to single user systems - in multiuser, it means the operator) tells
the system that he wants that task to hog the system. It means that the
user can stop a runaway task - by hitting some control key or sequence,
assuming that he wasn't dumb enough to set the runaway task's priority
higher than the task that services the key interrupts. It means that
if a programmer makes a boo-boo and codes (in C, lets say,
      while(1); 
or
label1:
       goto label1;   ),
that he can stop it. It means that if an errant program executes a
WAIT_UNTIL_AN_INTERRUPT_HAPPENS instruction, that the OS checks to
make sure that some interrupt is enabled (i.e. a disk read waiting to complete,
or checks that the keyboard interuupt is working).

    It is hard to see that non-premptive multitasking can do all these 
things.

    OF course nothing will help if the OS kernal screws up.

Doug McDonald