21 Nov
2014
21 Nov
'14
1:04 p.m.
My understanding (perhaps incorrect, if so, someone please correct me) is that
the wart-level-detail answer to this question is that '_blank_ RX02 floppies
can be created on anything that can create RX01 floppies', but that RX02
floppies _with data on them_ can only be created on RX02 drives. I.e. an RX02
is fed RX01 floppies, which it then writes in the unique-to-DEC double density
RX02 format. (As Chuck explained, the _headers_ are in the standard IBM form,
but the _data_ part of the sectors is written in a DEC-specific double-density
format.)
Almost, at least to the user.
An RX02 drive can reformat an RX01 disk as RX02. What it can't do is format
a blank disk. So if you make an RX01 formatted disk (essentially possible on
any machine with 8" drives that supports an FM (single density) format, then
the RX02 can turn it into an RX02 disk.
Incidentally, there were Qbus cards (I have never seen a Unibus one) to
handle RX02 disks using normal 8" (Shugart 800, etc) drives. Some of those
I think could format a totally blank disk.
-tony