[BBC-Micro] Some ADFS / WDC 1770 questions.

[Chris Johns]

On Fri, 10 Nov 2006, Jonathan Graham Harston wrote:

> Drive 4/5/6/7 are always floppy drives 0/1/2/3
>
> If (configured HARD) AND (hard drive interface present) THEN
> Drive 0/1/2/3 are hard drive 0/1/2/3
> ELSE
> Drive 0/1/2/3 are mapped onto 4/5/6/7
>
> In other words, with no hard drive present, drive 0 is the first
> floppy drive, as is drive 4. With a hard drive present, drive 0 is
> the first hard drive.

I guess this is all so that on a beeb (where you can't configure the 
drive) if you shift-break on a hard disc system, you'll boot from that, 
and if you have no hard disc, you'll boot from floppy.

> This is oddly the opposite way around to 32-bit ADFS, where
> 0/1/2/3 are floppies and 4/5/6/7 are hard drives.

Yeah, having used RISC OS with hard drives before I used a beeb with hard 
drives, this seemed odd. I guess at the time most machines were floppy 
only, so they went with :0 as the first floppy drive.

Cheers

Chris
-- 
  Chris Johns <chris at lessthan3.org.uk>