[fdutils] Need help with weird floppy issue

Simon Owen snowen at gmail.com
Mon Mar 13 12:31:21 CET 2006

On 3/8/06, I wrote:
> Another possibility is to use multi-pass interrupted formatting.

I tried just that, and it can indeed be written in the following 5 stages:

  sectors=12, size=3, gap3=15
  sectors=21, size=2, gap3=2
  sectors=19, size=2, gap3=5
  sectors=30, size=1, gap3=4
  sectors=2,  size=6, gap3=1

The track is written back-to-front, with later sectors positioned
first.  In each case, the format is terminated shortly after the
controller starts writing the final sector, so that later sectors are
not overwritten.  The first 4 entries create sectors 6-5-4-3 with the
final one creating sectors 1-2.

The formatting leaves filler sectors on the track, so data must be
written to each of the normal sectors to cover them.  As a final
precaution I'm verifying that all sectors still exist, as even small
variations in format positioning can cause overlaps.  I've got a
Windows (2000/XP/2003) sample showing this in action, if anyone is
interested.  I'm not sure it's currently possible to do it under

Despite the disk format matching the 1880K MAME description, it's
still not fully working in the real System 24 machines yet.  Something
fails later in the boot process for as-yet unknown reasons...


fdutils mailing list
fdutils at tux.org

More information about the Fdutils mailing list