Re: Multitasking apple II

[Kevin <followthelink@bottomofpost.com>]

On Thu, 16 Sep 2004 21:22:46 GMT, bill_gates@microsoft.com (Simon
Williams) wrote:

>I imagine this would require the OS to take a "snapshot" of the
>currently running 128K and move it up, and then move a different 128K
>bank into main memory.... maybe this is similar to how Proterm is able
>to switch between terminal and editor.
>Now this is well beyond my abilities, since I'm sure a confusing web of
>GOTOs in Applesoft won't quite do the trick... but it seems like the
>kind of thing that might add to the utility of the Apple II without
>having to bother with a 32-bit processor or create some Frankensteinian
>concoction of orphaned motherboards ;-)
>Of course, it also occurs to me that if this were feasible it would
>likely have been done by now.


interesting idea.  This excact same concept was used on memory
expanded atari 800xl's and 130xe's (both 6502 based machines as well).
It was done thru software called that as you say took a "snapshot" of
the current state of the computer and allowed you to switch between
two states (128k allowed for 2 states, this prog was most useful with
800xl's that were moded for 256k or 1mb)  I wouldn't call this
mutitasking, but it was my first introduction to the concept.  This
proves it is feasible.






kevin



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