Open-source floppy reader: the data separator/sync-er works! - test-drb@ccmp.vtda.org

10 Apr 2007

Jules Richardson wrote:
...
  I think I'd mentioned this privately to Chuck the
other week, but I'm not sure
 if "playing back" raw data to a drive will even work, given that there will be
 slight differences in drive RPM between drives: a track buffered on a "slow"
 drive would run past the end of track on a "fast" drive by a few bits. 
Besides that, there's the fact that the copy would have twice as much
peak shift and jitter as the original, and be unreadable or barely readable.

...
  It
 makes me wonder if the only way to do a 100% reliable write is to interpret
 the data that you're writing, lay down a format (which is guaranteed not to
 overflow available space), then lay down the actual data. 
Right. And you also need to verify the CRCs, and reread any sectors that
failed, in case of dropout.

-- Adam