[Coco] COCO4 Emulator

John Donaldson johnadonaldson at sbcglobal.net
Fri May 5 20:20:32 EDT 2006

What I would love to have is what I call a COCO4 emulator program. There 
are three COCO3 Emulators (JC/JV, Kriel, nd Mess), which are being used. 
I believe that any or all of them could be modified to include the items 
that I think would make a COCO4 emulator. Something along these lines.

COCO4 Emulator

1. Add 640X480 and/or 800X600 screen support.
2. Extend the number of colors that can be used at the same time.
True 256 colors.
3. Increase the memory to 2 or 4 MB for both DOS and NitrOS9. Make it 
fully accessible for
programming, not just for RAM disks and such. Mabey not for DOS, but cn 
be done for NitrOS9.
We already have the 2M mode in the JC/JV Emulator, but I don't think it 
is all avalible for
4. Change the memory mapping under NitrOS9 to 2K blocks instead of the 
8K blocks. Too many
times I have seenwhere a 8K block had to be allocated and have 6K of it 
wastied. IFRC, I once
read that Motorola had a Memory Manager chip for the 6809 that did run 
in 2K blocks.
5. Extend the boot process in NitrOS9 so more drivers can be loaded. I 
think Boisy figured out how to
make NitrOS9 L3 use a larger boot file.
6. Add support in NitrOS9 for using Ethernet Cards, sound cards and etc. 
Chris Hawks now has a CDRom reader program for NitrOS9 L3, with the 
expanded memory, larger boot file, why can't a IP Manager be written? 
Letting the emulator run at CPU speed should speed up the access IMHO.
7. Optimize the emulator speed to take advantage of the PC CPU speed. 
That is allow it to run as
fast as possible.
8. Make the PC floppy drives Read/Write/format real DOS and NitrOS9 
disks. I think Kriel's already
does this.

With the faster CPU’s of today and letting the emulator run at full PC 
speed, it should be fast enough to handle all of these items. Mabey not 
all of theses are feasible but some, if not most should be. The expanded 
screen sizes and colors should not be a problem if the memory is 
expanded to 2 or 4 Meg.
For those COCO3 programs that would need to run at standard COCO3 
speeds, a switch could be included to slow it down. I fully believe that 
it can still be backward compatible to a standard COCO3.

John Donaldson

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