Re: "Real" Multitasking (Re: GNO questions...)

[rhyde@ucrengr.ucr.edu (randy hyde)]

Oh No!  The great "Macs Do/Don't really multitask debate" again.

For those who want to use the terms from O/S which have been in use for
30 years, here they are:

Multiprogramming: multiple programs in memory, tasks switch on I/O or other
OS calls.  This is what Apple calls "cooperative multitasking."  It is not
multitasking if you want to believe the people who created the term, it is
multiprogramming.

Multitasking: By definition this is a superset of multiprogramming which
includes preemption (switching on I/O or OS calls is still allowed!).

The original poster to which I am replying (I hate people who complain
about others wasting "bandwidth" and then copy messages verbatim) made the
claim that multitasking is less efficient.  I'd like an explanation of why
this statement was made.  It is very easy to give examples which show
either method is more "efficient", depending upon your definition of
efficiency.  Also, the statement was made that multiprogramming systems
do not need to save as much machine state as multitasking systems.
This is totally false.  Perhaps the poster was confusing lightweight
processes (threads) with heavyweight processes?