22 Jan
2003
22 Jan
'03
6:44 a.m.
At 12:45 22/01/2003 -0500, you wrote:
Quoting pete(a)dunnington.u-net.com:
From what I recall from doing it many years ago, one could achieve a (low
capacity) dual-format disc by formatting and copying the files over on a 40
track drive, then putting the disc in an 80 track drive, and formatting *as
40 tracks* (so that it only did the first 40) and copying over the same files
in the same order. Oh, you had to copy over a suitably sized dummy file first
on each occasion (to skip the first half of the 40-track disc).
does that make sense?
On Jan 18, 16:16, Philip Pemberton wrote:
One has to be very careful with the formatting - there where several
different
FS formats - some with varying compatibility. (Talking about the file system
side here) The Master welcome disc used ADFS which was slightly more advanced
than the more common DFS that was used on the earlier Acorns.
I do have some scribbled documents which describe Acorn DFS in enough detail,
plus some sample code which will extract and create disc images which I can
send on (IIRC the code is actually on the web on one of the Acorn web
sites - I
can't remember which one though!)
dave Finally, does anyone know how some discs were
formatted so they were
compatible with 40-track and 80-track disc drives?
The way Acorn did that with
things like the Master 128 Welcome Disc was to
make all the directory entries (on track 0) point to tracks between 5 and
9, and 20 and 39. Track 20 on a 48-tpi drive is where track 40 would be on
a 96-tpi drive: