[Coco] Load .vhd image into Drivewire3

[Robert Gault]

Earl Casper wrote:
> How do you load a virtual hard drive image into Drivewire3?
>

Let's assume for the sake of argument that you have a Windows system. The 
Drivewire3 server has two default disk types in the selection window, .dsk and 
os9. No other images will be visible in the directory.
No problem! Either enter *.* or better *.vhd and you will see all or just the 
.vhd images in a directory. Highlight the desired image and it will mount 
exactly as a .dsk or .os9 image would.

Perhaps you meant to ask, how do you use a .vhd image with DW3, which is a 
different issue. The Disk Basic offset value in the HDBDOS rom MUST match the 
offset in the .vhd image. If there is a match, then you can use the .vhd image 
exactly as you would in MESS, VCC, or a real Coco with a hard drive.
If the offset values do not match, then you are stuck unless you are using a 
Coco3 or can burn an alternate EPROM.

With a Coco3, you can just POKE into memory the required offset value so that 
the EPROM matches the .vhd image. The default value for .vhd images is $5A000 
bytes to the beginning of the Disk Basic section.
POKE&HD938,5:POKE&HD939,&HA0 with a Coco3 will make the ROM match the default 
.vhd format.

If you use a Coco3 with a standard DOS and LOADM"HDBDOS" from a disk or CLOADM 
from tape, the procedure is a bit more complex but you still must have the 
offset values match.