Date   : Wed, 22 Aug 1990 09:20:03 GMT
From   : eru!luth!sunic!mcsun!hp4nl!charon!jurjen@bloom-beacon.mit.edu (Jurjen NE Bos)
Subject: Z80 multitask

clldomps@praxis.cs.ruu.nl (Louis van Dompselaar) writes:

>Is there anyone who has had some experience in using multitasking
>on a Z80 system? Please let me know what is, and what is not, possible...

>Louis
>clldomps@praxis.cs.ruu.nl

Easy!  We (4 friends and me) built a multi-user Z80 systems already years
ago, featuring 512K RAM, two real floppy drives while the users thought
they had 4 floppies each (but if you wanted to read something, you had to
walk over and insert your floppy), 5 terminals, etc.
The system is still running, and today they are working on a LAN, hard disk,
and more goodies.

The trick is to get some coprocessors for things like key scanning, disk I/O,
and other work that tends to eat away cycles.  The CPU can then start doing
only the more useful things.  But of course, we had a lot more performance-
increasing tricks...
--
|                 | "Never imagine yourself not to be otherwise than what |
| Jurjen N.E. Bos | it might appear to others that what you were or might |
|                 | have been was not otherwise than what you had been    |
|  jurjen@cwi.nl  | would have appeared to them to be otherwise."         |


End of INFO-CPM Digest V90 Issue #132
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