0040h:008Bh           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