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From: mjs@hpfcso.FC.HP.COM (Marc Sabatella)
Newsgroups: comp.sys.atari.st
Subject: Re: Multitasking
Message-ID: <7340086@hpfcso.FC.HP.COM>
Date: 15 Feb 91 19:00:44 GMT
References: <74457@bu.edu.bu.edu>
Organization: Hewlett-Packard, Fort Collins, CO, USA
Lines: 17

>    software, but multitasking under software is not multitasking.  A
>    multiprocessor board is neccessary for true multitasking.

Not by any reasonable definition of multitasking I've ever seen.  Amigas
multitask, Unix multitasks, virtually every other "real" operating system out
there (depending on how you label MS-DOS) multitasks without special hardware.
Well, maybe an MMU, but no multiprocessors are required.  Read an OS text to
learn the difference between "multitasking" and "multiprocessors".

My bried summary: "multitasking" is achieving the illusion of doing more than
one thing at a time, to give you a convenient user interface.  But the total
CPU time required to execute two processes is the same sequential or parallel.
A "multiprocessor" is something that will execute >1 instruction at once, where
those instructons may all come from the same process - ie, one need not
multitask to take advantage of a multiprocessor.  The sole purpose of a
multiprocessor is to make things run faster; it is entirely orthogonal to the
issue of multitasking.