19 Oct
2011
19 Oct
'11
8:58 a.m.
On 18 Oct 2011 at 23:25, Eric Smith wrote:
It would be interesting to see whether the 1781 with a
suitable
DEC-M2FM encoder/decoder could be used to read/write double density
RX02 format.
WD1781 chips are very uncommon, proably because they were fraught
with problems (mostly hangs). There was a reason that WD dropped it
from its product line--I think they hated it.
I've got a couple of Durango F85 systems here that use 100 tpi
drives and WD1781s to handle group encoding and get about 980K of
usable space on a floppy. I've seen a couple of other systems using
it, but don't recall what they were.
I don't see why one couldn't handle the MFM" RX02 encoding in a
similar manner using one.
--Chuck
(FWIW, the 1781 is essentially a "naked" 1771 with (IIRC) with the FM
modulation removed. The command set is the same as the 1771.)