I personally doubt it's a floppy controller, as the parts list seems wrong. Why would a floppy controller have a RAM chip on it unless it also had a microcontroller, which this lacks? And if it were a controller designed to drive MFM floppies wouldn't it be logical for it to incorporate an FDC controller chip? It doesn't look to me as if there's enough discrete logic on that board to run a floppy drive otherwise. (There's no UART so it'd have to "bit-bang" the data stream, which I guess might be possible given that's essentially what the Disk ][ controller does, but then what's the RAM chip for again?) The use of a 34 pin ribbon cable doesn't really shed any light on the subject, as it was a terribly common connector. (TRS-80s, for instance, have identical looking 34 pin card edge connectors for parallel printers and disk drives. You had to know which port was which.)

Here's a link to an MFM controller card for Apple IIs. Note the use of an FDC chip, in this case an Intel 82077

The card makes more sense interpreted as a parallel I/O port, but not necessarily for a printer. As to exactly *what* went on the other end of that cable... perhaps examining the contents of the onboard ROM would provide some hits.