[Color Computer] Re: [coco] What would it take to really emulate a coco on a modern PC?

[Larry Shurr]

--- In ColorComputer at yahoogroups.com, "George Ramsower" <yahoo at ...> wrote:
>
>  What would it take to really emulate a coco on a modern PC? 
> This would include a plug in board to emulate all the I/O 
> stuff a coco has, including the expansion port.

Hmmm... haven't heard much talk of Coco emulation projects in awhile.
 What would you like to emulate that isn't already available in one of
a number of readily-available software emulators?  E.g., Mr. Jeff
Vavasour's excellent Coco II & III emulators (see
http://www.vavasour.ca/jeff/).  I bought his Coco III emulator years
ago before it became freeware, though this entailed replacing the 6809
emulation with unencumbered code which is slightly less efficient then
the original CPU emulation.  I considered the payware version to be
well worth its low price.  On a typical modern PC, the small
performance difference between the payware and the freeware versions
was effectively subsumed and rendered meaningless long ago by the
ever-increasing speed of Intel '86 processors. 

It is true that even Jeff's excellent emulations are not bit-perfect
(The Sockmaster's Bouncin' Ball Demo for the Coco III doesn't work,
for example) and of course, the little interface projects that were
once popular with the Coco hardware cannot be done.  Is that what
you're looking for?

>  I think this would be an expensive project. I'm sure this 
> would not be easy. However, this would be really fun to have 
> a real coco on a PC.  It would be faster than a bullet,, 
> more powerful than a locomotive,  able to leap tall buildings 
> in a single bound.....  I hope you get the idea.

The Vavasour Coco III emulator running on my 2 Mhz P4 laptop can be
dialed up to run absurdly fast, making the proverbial speeding bullet
say, "Huh? What was that?"

Many years ago, it was proposed to design and build a Coco 4 which
would provide backwards compatibility to Coco II & Coco III in some...
disputed... form.  I say disputed because everything about this
proposal was disputed... everything.  There was a great deal of
discussion, some of it quite interesting, but there was more than a
little flamage and snapping of tempers, as well.

At least one faction declared that the Coco 4 had already been built
and it was known as the Amiga.  Of course the Amiga had no Coco
compatibility, nor was there an Amiga-based Coco emulator, but the
Amiga faction considered it the "spiritual" successor to the Coco.  I
won't say they were wrong, but even then, the Amiga was effectively
dead (I realize that the Amiga lives on, after a fashion, in a Power
PC-based implementation even today, but it's a niche machine and lot
of people have never even heard of it).  Another faction claimed that
the Macintosh was the Coco 4... but that idea was pretty much shouted
down.

Other proposals included a PC-based software implementation and a
number of hardware-based implementations, both free-standing and
plug-into-a-PC cards.  Proposed CPU's that I recall were Intel 486 and
Pentium CPU's (I seem to recall that Intel had a low-cost 486 with
integral interrupt controller and I/O intended for embedded control
applications -- sort of a new edition of the 80186), Moto PowerPC
(fairly expensive at the time), and the Moto "Coldfire," an embedded
control processor more-or-less based on the 68000 family.  And that
discussion was just about implementation.  As for what a Coco 4 should
do, well there was no agreement there, either, though the competing
implementation proposals dominated the argument.  I liked the Coldfire
idea and thought it the most serious proposal.  Moto sold a cheap
design kit that would have made a good starting point that would cut
down on manufacturing and/or kitting requirements, but I was willing
to support just about anything that might arise from a consensus. 
However, looking back on it, the lack of consensus may only have been
a symptom that there wasn't a critical a mass of support available to
realize a populist-created Coco 4 in any form.  Possibly, there were
too many legal encumberences, e.g. Tandy and Microsoft licenses, as well.

> 
>  I'm sure I'm dreaming.... No.. not sure, certain.
> 

The available evidence suggest that you're right.

Larry





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