Disk image in NADOL format

CATALOG will be at track $00, sector $03 to track $00, sector $09 each entry consists of $10 bytes, which are:

 00-0B - filename - if file is deleted, first byte will be FF
 0C-0D - filesize (low byte first)
 0E - track of track sector list sector
 0F - sector of track sector list sector

TRACK/SECTOR LIST FORMAT

 pairs of track/sectors in order. up to 128 entries [assumes that no file can be > 128 sectors]

SECTOR USAGE BITMAP is at Track $00, Sector $2, from bytes $20 .. $65 bitmap is of form:

 ----hi bit--
 |             |
 01234567 89ABCDEF
  ^^^^^^      ^^^^^^^
   low byte    hi byte