Disk: Acorn DFS
===============

Acorn DFS disks are pretty standard FM encoded IBM scheme disks, with
256-sectors and 0-based sector identifiers. There's nothing particularly
special here.

DFS disks are all single-sided, but allow the other side of the disk to be
used as another drive. FluxEngine supports these; read one side at a time
with `--heads 0` or `--heads 1`.

DFS comes in two varieties, 40 track and 80 track. These should both work.  For
40 track you'll want `--cylinders 0-79x2`. Some rare disks are both at the same
time. FluxEngine can read these but it requires a bit of fiddling as they have
the same tracks on twice.

Reading discs
-------------

Just do:

```
fluxengine read acorndfs
```

You should end up with an `acorndfs.img` of the appropriate size for your disk
format. This is an alias for `fluxengine read ibm` with preconfigured
parameters.

References
----------

  - [The Acord DFS disc format](https://beebwiki.mdfs.net/Acorn_DFS_disc_format)

