Date   : Thu, 21 Jan 2010 02:00:26 +0000
From   : philpem@... (Philip Pemberton)
Subject: Disc formats -- DFS/ADFS and the Master Welcome Disc

Hi guys,
I'm not sure if I've mentioned my disc analyser project here, but 
basically it's a "magic box" (plus software) that plugs into a USB port 
and makes a transition-timing-level image of a floppy disc, which can 
then be decoded, written back, etc.

I've just read in a BBC Micro disc -- specifically the dual 40/80 track 
Master Welcome Disc. Oddly enough, track 0, head 0 seems to be utterly 
mangled -- DiscTool IDs it as "noise". Tracks 1 and 2 (both heads) seem 
to be fine -- they're ID'd as "MFM, modified IBM System 34/ECMA format". 
I haven't tried decoding any of the other tracks.

Does anyone know if t00h0 is formatted differently on the Master welcome 
disc?

I'm also interested in any information folks might have on the DFS and 
ADFS formats (especially the 800K and 1.6MB ADFS "E" formats used on the 
Acorn Archimedes/RiscPC systems). I noticed JGH has some info on DFS and 
the earlier versions of ADFS, but ADFS-E info seems to be a bit thin on 
the ground.... :-/

Thanks,
-- 
Phil.
philpem@...          
http://www.philpem.me.uk/