13 Sep
2009
13 Sep
'09
9:56 a.m.
M2FM recording is pretty easy--the rules are less complicated than MFM; I suspect the
reason that it isn't used today is that it's inherently less reliable. For a
decent description of it,
see page 5 of the Shugard SA800/801 theory of operation manual on Bitsavers.
Intel used it on their MDS; I think HP used it for a short time as did Lanier for their WP
gear.
Other than that, it's pretty uncommon. The only monolithic floppy controller that I
know of
that supported it was the 8X330 chip for the Signetics 8X300 bipolar microcontroller.
--Chuck