On 9/10/23 12:39, Fred Cisin via cctalk wrote:
  On Sun, 10 Sep 2023, Chuck Guzis via cctalk wrote:
  There are 40 track derivatives; used for word
processing, particularly
 on some Brother models.  No big deal; when reading those, one simply
 double-steps a "normal" drive.  In any case, as far as I recall, they
 all used Brother's proprietary GCR encoding.  I've processed a couple
 hundred of those. 
 With the exception, the Epson Geneva PX8 40 track 3.5" was MFM 
Got some of those in my rogue's gallery too.  The thing that seems to be
lost on many is that legacy (i.e. Shugart-interface) floppy drives are
very dumb devices.  Pretty much don't care what you put on them, so long
as it satisfies the bandpass requirements.
--Chuck