This formatter is a version of HForm, hacked to support IDE drives during
development of the IDE driver, and was not intended to be used other than
during development. It consequently has all the problems of previous
versions of HForm.

If the program bombs out when initialising the disc with "Unknown or missing
variable", it is because the drive is too big for Buf%. Simply increasing
the size of the buffer fixes this. Ideally, the code would check the size
before writing beyond its limit!

WimpSlot needs to be big to accomodate drives with large cylinder size. It
may be necessary to reduce it for 1MB machines and rely on the next slot
being large on machines with large drives.

Defects are currently handled in the standard way: they are stored in the
defect list for FileCore to avoid. A better version would use the format
code to map alternate sectors for bad ones if the drive supports it.
