itsy bitsy Unix

[Roger Merchberger]

Rumor has it that Eric Smith may have mentioned these words:
>Paul Koning wrote:
> > Come to think of it, cooperative multitasking is trivial, you can code
> > your own.  It looks like this:
> >
> >     for {;;} { task1(); task2(); task3; /* etc */ }
>
>That's only a very restricted case of cooperative multitasking, though
>it can nevertheless be useful and effective for many problems.

True...

[snip]
>Many people have gotten the idea that cooperative multitasking is "bad",
>or that it isn't "real" multitasking.

It isn't! ;-) Joking, but having used a pre-emptive multitasking OS on an 
8-bit machine for a lot of years, which ran better / more stable, heck - 
quicker than Win31 on a 386, one may be able to see why I have a bit of a 
jaundiced eye towards cooperative multitasking systems...
;-)

Which is why I'm still kind of surprised no-one's brought it up yet: OS-9 
for the 6809 CPU. Granted, it's for a micro and not a mini (but heck, so's 
winders, MacOS & AmigaOS) but there is a freeware version out with source 
and everything (and the last updates were less than a year ago, and there's 
nightly CVS snapshots available) here:

http://www.nitros9.org/

Originally, NitrOS9 was a set of patches to use the enhanced capabilities 
of the 6309 under OS-9 Level 2 - but they've basically rewritten the OS 
around the patches, not only for Level 2, but even backported it to Level 
1, which will run on the coco 1 and 2, and possibly even the Dragon.

Oh, and it's even rather unix-like! ;-)

I had OS-9 Level 1 easily running in 24Kbytes (altho 64K RAM was necessary 
in the computer), and IIRC just to see if I could do it, I had a bootdisk 
that shoehorned it into 16K, but there were precious few modules in memory 
for that.

It's written in 6809/6309 assembly, so that might get you started...

>   In reality, there are many
>scenarios in which cooperative multitasking is a better solution than
>preemptive multitasking.  Either type can get you into trouble if you're
>not careful.

That's kinda like saying "Sword swallowing can get you into trouble if 
you're not careful..." ;-)

Laterz,
Roger "Merch" Merchberger

--
Roger "Merch" Merchberger -- SysAdmin, Iceberg Computers
zmerch at 30below.com

What do you do when Life gives you lemons,
and you don't *like* lemonade?????????????