[Coco] Minor issues with MESS/MAME

[Robert Gault]

As a result of recent topics on using a Coco emulator, MAME/MESS has been mentioned. This emulator 
works on Linux systems which would make this a preferred emulator for some on the list.

I've been playing with the latest Windows version of MAME 1.99 which seems error free so far. I have 
found several issues that are bound to cause confusion. This version supports the HD6309 cpu on the 
following versions: coco, coco2, and coco3 NTSC. However there is no method for switching between 
the M6809 and the HD6309 as there is with VCC.
There is no HD6309 support for the coco3 PAL nor the coco3 with HDB-DOS.

Since the most direct way for MAME to work with Drivewire is to select in MAME the "Color Computer 3 
(NTSC;HDB-DOS)" from the MAMEUI menu or the MAME command line; mame coco3dw1.
If you do that, emulation will start and you can access Drivewire and even boot to a NitrOS-9 Becker 
disk as long as it is a 6809 disk.

Now there is a way to emulate the 6309 while using Drivewire. You start coco3h emulation, the 
ROM/coco3h directory needs the disk11.rom, but you mount in the active cart slot a Becker HDB-DOS 
rom. Then you can boot a Becker HDB-DOS 6309 disk mounted in Drivewire.
Just make sure to have the required $D938 offset for the .dsk or .vhd you have mounted in DW.

There are a few other tricks for using MAME to best advantage. Anyone having problems should post to 
the list or you can email me directly.

Robert