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From: jurjen@cwi.nl (Jurjen NE Bos)
Newsgroups: comp.os.cpm
Subject: Re: Z80 multitask
Message-ID: <1987@charon.cwi.nl>
Date: 22 Aug 90 09:20:03 GMT
References: <3696@ruuinf.cs.ruu.nl>
Sender: news@cwi.nl
Lines: 24

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."         |