Date   : Sat, 29 Aug 1998 16:35:30 +0100 (BST)
From   : Dave Gilbert <gilbertd@...>
Subject: Re: Difference between ADFS and DFS

On Sat, 29 Aug 1998, Alan wrote:

> Could somebody tell me te difference between ADFS and DFS please!

Quite a bit!

DFS uses a very simple non-hierarchical directory structure capable
of storing 31 files in the directory (there are hacks to have a small
handful of directories).
DFS uses a single-density disc format storing 100K on a 40-track/single
sided disc. You can also run it at 200K for 80-track and you can use two
sides of a double sided disc as effecitvly independent discs.
File names are 9.1 (or was it 7.1)

ADFS uses a hierarchical directory structure; although it is still
limited to a fixed number of entries per directory. (Traditionally 87 I
think, but I think there is a new version on the latest version of RiscOS
capable of more).
It uses a higher density format capable of storing 160K on a
40-track/single sided disc.  A double sided disc is treated as a single
entity and can hold 640K on the beeb version of ADFS. (On Archimedes the
ADFS can store 800K on a double sided 80-track floppy in one of two
different formats).
I think its names are 10 character long.

ADFS was available for Model-B's to run the Hard drives, but not for
floppies until the advent of the 177[02] based controllers (for Model-B's
, B+'s, and Masters).

Dave

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