NAME
        TD_GETDRIVETYPE -- return the type of disk drive for the unit that was
                           opened.

   FUNCTION
        This command returns the type of the disk drive to the user.
        This number will be a small integer and will come from the set of
        DRIVEXXX constants defined in <devices/trackdisk.h>.

        The only way you can actually use this command is if the trackdisk
        device understands the drive type of the hardware that is plugged in.
        This is because the opendevice() call will fail if the trackdisk device
        does not understand the drive type. To find raw drive identifiers see
        the disk.resource's DR_GETUNITID entry point.

   IO REQUEST INPUT
        io_Device       preset by the call to opendevice()
        io_Unit         preset by the call to opendevice()
        io_Command      TD_GETDRIVETYPE
        io_Flags        0 or IOF_QUICK

   IO REQUEST RESULT
        io_Error - 0 for success, or an error code as defined in
                   <devices/trackdisk.h>
        io_Actual - if io_Error is 0 this contains the drive type connected to
                    this unit.

   SEE ALSO
        td_getnumtracks, <devices/trackdisk.h>