Date   : Sat, 13 May 2000 16:38:57 +0100 (BST)
From   : Dave Gilbert <gilbertd@...>
Subject: Re: DFS vs. ADFS

On Sat, 13 May 2000, Thomas Harte wrote:

> Hello,
> 
> I am wondering if the ADFS ROMs are meant to be able to read DFS disks? And

No they are not - the disc formats are completely differently (both at the
low level and the content)

> if not, is there a 'dfs disk image to adfs disk image' converter about? If
> not, and if I wrote one, would it be worth releasing to the public?

Yeh why not.

> I ask because I implemented WD1770 emulation in my Electron emulator
> yesterday, and tried '*cat' only to get 'Broken directory', even though I
> can verify via a small BASIC program that the first six sectors of the disk
> have been correctly read by the Electron into the area used by the Electron
> ADFS as the catalogue buffer. It then occurred to me that my only evidence
> that the disk image (downloaded from the 'net) should work came from trying
> it on a BBC emulator with only a DFS filing system.

Yeh that sounds like a reasonable problem; you should be able to tell from
the image length as well.  DFS discs tend to be multiples of 100K, ADFS
discs are multiples of 160K.

> Also, while I'm here, what filing systems for floppy disks besides DFS,
> Watford DFS 62 and ADFS exist?

Solidisk did one for the beeb which I think used the 177x.

Also I think there is a 177x DFS from Acorn somewhere, so try and get hold
of that.

Dave

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