On Jan 22, 12:45, dave_at_cirt.net wrote:
> Quoting pete_at_dunnington.u-net.com:
> > On Jan 18, 16:16, Philip Pemberton wrote:
> >
> > > 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:
>
> 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.
Yes, I'm aware of that. The Master Welcome Disc appears to the system as
an ADFS S disc (S means "small format", 160K), ie as 40-track single-sided
disc. It just happens to be made in such a way as to be readable in
40-track and 80-track drives.
I created a few discs like that at the time. I did it by hand, but I
believe eventually someone made a utility or ROM to do it.
Now if you think that's wierd, how about the disc I have (also for a BBC)
that has three separate sets of data on it, all in DFS format?
--
Pete Peter Turnbull
Network Manager
University of York
Received on Wed Jan 22 2003 - 15:48:00 GMT