[Coco] Vcc and real floppy disks

[Robert Gault]

Darren A wrote:
> On 9/26/08, Robert Gault  wrote:
>>  < snip >
>>
>> I should also point out that one can (and I have) expand the OS-9 drive
>> tables in the same manner so that both true double sided disks and dual
>> singles can be used at the same time.
>>
> 
> ---
> 
> Looking at the source code for the WD1773 driver in Nitros-9 reveals
> that the "Side Compare" bits are not being used when commands are
> issued to the FDC. I imagine the same is probably true for OS-9
> drivers. If those drivers had been implemented 'properly', VCC could
> simply use the command bits to determine how to specify the target
> sector.
> 
> Since this isn't the case, it looks as though some kind of
> configuration setting would have to be in place to tell VCC whether a
> disk is true double-sided or has single-sided formats on each side.
> VCC could perform the configuration automatically by issuing an
> IOCTL_FDCMD_READ_ID to fdrawcmd.sys and examine the contents of the ID
> field returned.
> 
> Darren
>

If you look at the latest code for rb1773 you will find

* Drive control register bit mask table
* May want an option here for double sided SDDD disks ex. RG
*        fcb   $1      drive0
*        fcb   $2      drive1
*        fcb   $41     drive2
*        fcb   $42     drive3
*        fcb   $4      drive4
*        fcb   $44     drive5

L0372    fcb   $01            Drive 0
          fcb   $02            Drive 1
          fcb   $04            Drive 2
          fcb   $40            Drive 3 / Side select

The side select is being used correctly in the current code but Boisy 
has not bought into the need for treating the back side of disks as 
separate singles. Nevertheless, anyone with the source could create a 
custom floppy driver.
It is even easier to make the change in DOS under Basic. All you need is 
to change the drive table without checking the rest of the code to see 
if it will work.