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From: rhyde@ucrmath.ucr.edu (randy hyde)
Newsgroups: comp.sys.apple2
Subject: Re: Multitasking on a II
Message-ID: <10425@ucrmath.ucr.edu>
Date: 10 Dec 90 15:39:00 GMT
References: <1990Dec6.171148.9281@ux1.cso.uiuc.edu> <10395@ucrmath.ucr.edu> <2433@unsvax.NEVADA.EDU>
Organization: University of California, Riverside
Lines: 16

All you need to do multitasking on a II is a timer interrupt.
I used an old 6840 timer chip on a board from some (now history)
peripheral manufacturer.  I managed to get four processes running
at once (at $800, $2000, $4000, and $6000).  Needless to say, these
processes were highly aware of one another.  I did not attempt to
take the project any farther than that.  To truely implement
multitasking on the II you need either memory management or
specially written applications.  I didn't have memory management
and I wasn't willing to write all the software myself.
When the GS came out, I said "aha, reasonable memory management"
and attempted to write "Multi-ANIX".  Alas, GS/OS has some
problems with multiprogramming so I eventually scrapped that
project as well (Although GS/OS does not allow true multi-tasking
or multiprogramming, it can support light-weight processes
very well).
*** Randy Hyde O-)