[Coco] Another Coco Virtual Disk Util

Robert Gault robert.gault at att.net
Sat Oct 19 15:32:19 EDT 2013


Walt,

There are a few more problems with EmuDisk.

With a .vhd disk, the Disk Basic drives are numbered 0-255 not 1-256 as in your 
program.
There does not seem to be any provision in your program (at least I can't figure 
it out) for creating a standard .vhd image which has the initial $5A000 sectors 
formatted for OS-9 and the remaining 256 drives of 18-sector, 35-track for Disk 
Basic. It doesn't seem possible to make a disk that large.

Much of this would normally be taken care of by the emulator ROMs (RGBDSO) which 
defaults to a $5A000 sectors offset before the Basic disk commands access the 
.vhd drive. HDBDOS for Drivewire has been causing problems as the offset is 
$000000. You can't create hybrid disks unless you POKE memory with the required 
offset value or tell Drivewire to use an offset.

Still, your program is looking very good and will be very useful.

Robert

PS. The source of the bad DD.FMT values seems to be the NitrOS-9 format command. 
The current version is using $03 even when it claims to be formatting a hard 
drive when it should be $82.



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