Date   : Sun, 26 Feb 2006 13:54:52 +0000
From   : Andrew Benham <adsb@...>
Subject: ADFS 'D' format ?

Now that I've found how to read my BBC ADFS (and DFS) disks
under Linux (http://www.adsb.co.uk/bbc/linux/), I'm thinking
about writing the missing 'oldadfs' Linux kernel module
(see 
http://lists.arm.linux.org.uk/pipermail/linux-arm/2002-November/004519.html)

(The existing Linux 'adfs' kernel module only copes with 'new map'
disks, which I think are 'E' and 'F' format).

I'm quite happy with 'S', 'M', and 'L' format disks (as
used on the BBC Micro for floppies and hard disks).
However if I'm to do the job properly, I ought to handle the 'D'
format disks as well - as I understand these use the 'old map',
but the 'new catalogue'.

As I recall, 'D' format arrived with Arthur and carried on into
RiscOS, and had 5 sectors of 1024 bytes per head per track (making
them 800k disks).
It's about 15 years since I had a Archimedes, so I've been trying
to piece together what a 'D' format disk looks like.  I've found
snippets like '77 entries per directory', and the magic string is
'Nick' rather than 'Hugo', but I need to know how the disk is
laid out.

I'm really looking for the Archimedes equivalent of section J.10 of
the BBC Master's "Reference Manual Part One".

I know I should be asking on an Archimedes list, but wondering if
anyone here has the answer ?

-- 
Andrew Benham         adsb@...       
Southgate, London N14, United Kingdom

The gates in my computer are AND OR and NOT, not "Bill"