[Coco] Hard disk image

[Robert Gault]

Mathieu,

To add to Bill's comments, you can also use MESS or VCC with RGBDOS to 
create a default .vhd hard drive. Just mount a 0-byte file such as 
test.vhd in one of these emulators and start emulation with RGBDOS. 
Enter DSKINI255 and you will get a 129Meg file with the last Basic drive 
formatted.

You will need a NitrOS-9 disk with appropriate drivers to format the 
OS-9 partition. If you use Disk Basic, you will want to run
10 FOR DR = 0 TO 255
20 DSKINI DR
30 NEXT
to format all the Disk Basic drives on the .vhd.

By changing the RGBDOS offsets at $D938-$D93A in the ROM, you can create 
.vhd drives of much larger sizes up to $1000000 sectors in the OS-9 
partition.
This applies to HDBDOS with real hardware as well as RGBDOS where 
changing the offset with a Coco3 is as easy as several POKEs. You will 
need to change the /H0 or /DD descriptors when you format the OS-9 
partition to accommodate non-standard drives. With .vhd drives mounted 
on Drivewire, you will need to either change the offset in your ROM or 
with DW4 change the offset and/or offsetdrv in the drive parameters.

Robert