CS80 describe of /dev/rfd9127:
  controller:   0x8001  installed unit word
                   100  max instantaneous xfr rate (Kbytes/sec)
                     4  SS/80 integrated single unit controller
  unit:              1  generic device type (flexible or removable media)
                091270  device number (6 bcd digits)
                   512  # of bytes per block
                     1  # of blocks buffered
                     0  recommended burst size
                  9872  blocktime (microseconds)
                    22  continuous average transfer rate (Kbytes/sec)
                  4500  optimal retry time (centiseconds)
                  8400  access time parameter (centiseconds)
                     8  maximum interleave factor
                  0x00  fixed volume byte
                  0x01  removeable volume byte
  volume:           39  maximum cylinder address
                     1  maximum head address
                     8  maximum sector address
                     0  maximum single-vector address
                     1  current interleave factor