Sure, the HP-85 supports floppy drives. I have a 9121 (dual 3.5" drive)
and a dual 5.25" drives that work fine with my HP-85. You will need a
Mass Storage ROM and an HP-IB interface but they work just fine.
The HP-85B have the MS ROM built-in. The 85B also has the capability of a
built-in Electronic Disc, if you add RAM cartridges.
RH writes about an HP-85.
Eventually hope to hook it up to a floopy drive
Are you sure the HP-85 supports floopy drives?
Not many machines do. :-)
Reminds me of the classified ad for a "sloppy disk drive"
that Byte reprinted many years ago. Someone commented
that the hole in the wall attested to the breakthrough
in technology.