Some thoughts on this day of working on MFM drives:
1) MFM drives are just going bad. They were always kind of meh in terms
of reliability, but I think even since 2019 (the last time I checked
these drives) things have gotten worse. Drives which were readable and
good then are now either shot or throwing errors and they have had an
easy 3+ years in my upstairs room.
2) There are at least two RQDX3 ROM sets. The earlier one does not
support the RX33 floppy and doesn't give any info during formatting. The
later version (Version 4) does support the RX33 and is a lot nicer.
3) Seagate drives seem to be pretty good, especially the 20mb ones. They
have no problems, work well, and are pretty right-sized for an RT11 system.
4) RD53 drives are weird. Their main failure is the drive head
positioner just gets stuck and needs to be worked loose. Unfortunately
that requires removing the lid. Fortunately there is a good filter in
the drive along with an air handler that runs air from inside the drive
body through the filter, then into the spindle where it is blown over
the heads. Result is a pretty clean drive on the inside and so far
opening the lid doesn't seem to be a recipe for instant destruction. Go
figure.
I may try an RD53 in one of my Pro/380's. It's about time I loaded up
the final version of P/OS, as I can use the Gotek floppy to load
everything instead of screwing with the RX50's. Or can I do that and
switch disks on the fly with a single Gotek... Hm.
5) For anything bigger, it's time to retire the MFM drives. Unlike
RL02's these things just were not that reliable when new and at this
point are kind of falling apart. I have not had any trouble with the
ESDI disks, but it might just be a matter of time. Perhaps I should look
into duplexing my 330mb CDC drive in the 11/84....
CZ
