[BBC-Micro] Some ADFS / WDC 1770 questions.
chris at lessthan3.org.uk
Fri Nov 10 10:23:12 GMT 2006
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
> 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.
Chris Johns <chris at lessthan3.org.uk>
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