[Coco] Vcc+DW4 to access real floppy drive on Coco-3 ?

[Kandur]

Thanks Gene.

Kandur

Monday, July 7, 2014, 11:10:29 AM, you wrote:
> On Monday 07 July 2014 11:59:29 Kandur did opine
> And Gene did reply:
>> Bill, what I wanted was, to access physical floppy drives on the Coco,
>> while running Nitro OS-9 on VCC. Drive ON/OFF don't seem to work
>> on the Coco's physical drives from OS-9.

>> Kandur

> That is because in nitros9, HDBDOS is not used and there are two different 
> descriptor "families".  You configure the bootfile to include the proper 
> /D0, /D1, or /D2 for the physical drives, but you have to configure /SH to 
> access the virtual drives.  If you have the drive space beyond the end of 
> the os9 "partition", then /SH, configured correctly, can access any 
> virtual disk, in however many groups of 255 that you have room for on the 
> hard drive.

> You have to dmode 3 variables in the descriptor to do this.

> The "stp", range $00 to $ff selects the vdisk within the group.
> wpc (1 hex byte) and ofs (hex int) are to be used to point at the first 
> sector of each group of 255 virtual disks.  So on my main hard drive, /SH 
> is currently set to look at the $80th, or 128th, disk in group 0, whose 
> address in wpc=1D and ofs=BB90.  Leave the dollar sign out of the dmode 
> command though, its not needed.

> Each additional group is done by adding to the $1D,BB90, the number of 
> sectors that 256 disks of 35 track, 18 sectors per track that a single 
> sided disk image would occupy.  The next group(1) then would have a 
> starting sector of $1DBB90 + $27600=$20,3190.

> Repeat, adding $27600 each time until out of drive space. ;-)

> I hope this helps.

> Cheers, Gene Heskett
> -- 
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