0:48Bh                   Diskette Media Control

 Length: 1 byte

    This byte is reserved for the PC, PCjr, PC XT dated 11/8/82, and the
    PC Convertible. For all others, this byte contains the last diskette
    data rate selected and the step rate.

                      Diskette Media Control

           7 6 5 4 3 2 1 0
           x x . . . . . .      Last Diskette Drive Data Rate (see below)
           . . x x . . . .      Last Diskette Drive Step Rate
           . . . . x x x x      Reserved

               Last Diskette Drive Data Rate (bits 7 and 6)

                        00        500K per second
                        01        300K per second
                        10        250K per second
                        11        Reserved