15 Sep
2009
15 Sep
'09
6:01 p.m.
On 15 Sep 2009 at 17:46, Eric Smith wrote:
The issue is that while M2FM channel encoding is
simple enough, there
isn't a *standard* for a floppy disk M2FM track format. Intel M2FM
floppy format is different from Texas Instruments TMS9909 M2FM floppy
format, etc. The marks, PLO sync fields, etc. are different. Also,
some of the systems that use M2FM actually use a *modified* M2FM
channel encoding, which arguably should be called M3FM but isn't.
No argument, but armed with the general principles of M2FM, one
should be able to suss out what the address marks, etc. are. I've
certainly that with much less to go on. (As in, "here's a diskette,
we don't know where it came from--and it isn't FM or MFM. Can you
convert it?").
--Chuck