Date   : Sat, 02 Sep 2006 15:12:24 +0100
From   : "Ian Wolstenholme" <BBCMailingList@...>
Subject: Re: *INFO

Thanks for that, this has reminded me of my first Beeb back in
1991.  It was a US BBC B complete with Faraday cage and came with
a Viglen drive and Viglen Utilities Disc.  This had a dual catalogue
facility activated with the *SWAP command which then accessed
a dummy file called "!.!!!!!!!" which presumably wrote the second
catalogue to the beginning of the disc and saved the other catalogue
in the file.

The good thing about it was that it would work with ordinary Acorn
DFS and you could copy the SWAP utility onto the disc instead of
reaching for the Viglen disc every time.

Has anyone else used this or even got a copy of it?

Best wishes,



Ian

----- Original Message -----
From: Mike Tomlinson
To:  bbc-micro@...
Sent:  Sat, 2 Sep 2006 10:03:23 +0100
Subject: Re: [BBC-Micro] Re: *INFO

In article <3B2E642150A34C0DB690644B5CD8094C.MAI@...>, Ian
Wolstenholme <BBCMailingList@...> writes

>But how does Watford DFS store the catalogue with 62 entries, presumably
>it needs twice as much space for it as an Acorn DFS disc?

Watford disks have two catalogues if formatted with 62 files - otherwise
they look just like Acorn discs. The second catalogue is in the two
sectors immediately following the first catalogue.

The disk title in the second catalogue has 8 x &AA bytes - this is how
you identify that the disk has two catalogues.

More at http://www.mdfs.net/Docs/Comp/Disk/Format/DFS

M.

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