[Coco] CoCo Board Stacking

[Frank Swygert]

Just an idea from a lurker: If you stack two CoCo boards in a case, 
couldn't they be linked in such a way that OS-9 could pass off almost 
any process to the second processor? A kernel would have to be running 
in the "slave" machine, but nothing else. Slave could be booted after 
the main machine came up by the same method the machines talk to each 
other, I would suspect, but the slave may need a special ROM routine. 
Heck, if you had to create a special ROM, a minimal kernel could just be 
burned in. Would make upgrades a pain, but how many times has the basic 
kernel been upgraded recently? Most upgrades are accomplished by add in 
modules/commands/etc., right? Then the main processor could pass (load) 
whatever commands, etc., to the slave board for execution. The slave 
board would make a great "no halt" I/O processor, for instance. I 
realize it wouldn't be as easy as it sounds, but one of you competent 
programmer types should be able to make good use of such a system. 
Writing a driver for the second machine would be difficult, I'd 
think.... or would it? A parallel connection between the machines would 
be preferred to the bit banger -- somehow connect the expansion ports 
together would be best. I remember enough to know the hardware isn't 
really in place for such a thing though. The thought just occurred to me 
that a 6809/6309 processor board with 64K (would be minimal chip 
count/work) and a real serial and parallel port could be made onto a 
board about the size of a disc controller for "secondary processing". 
Handling serial communications and printer buffering could be the main 
function, with capabilities of doing other processes. That would take it 
out of disc controlling unless you built that in too! To bad one of 
those neat multi I/O chips used in today's computers were never made 
with 8 bit communications in mind!
-- 
Frank Swygert -- Gulfport, MS
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