Date   : Sat, 02 Sep 2006 17:04:18 +0100 (BST)
From   : Greg Cook <debounce@...>
Subject: Re: *INFO

On Sat, 2 Sep 2006 10:03:23 +0100, Mike Tomlinson
<mike@...> wrote:

> 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.

Wouldn't you also want to check the first catalogue doesn't have a file
 starting before sector 4? (apart from the special !.!!!!!!!)
E.g. A screendump featuring vertical pinstripes, or an SSD file with a
badly-chosen disc title... *kaboom*
It also saves you from mangling DDOS discs.

Greg Cook
debounce@...
http://homepages.tesco.net/~rainstorm/



               
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