Int 13h, 00h            Reset Fixed Disk/Diskette System                  all

    Resets the fixed disk or diskette controller and drive, forcing
    recalibration of the read/write head.

        Entry   AH = 00h
                DL = Drive number

        Return  AH = Status of operation (See Service 01h)
                CF   Set if error, cleared otherwise

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    If DL is greater than or equal to 80h, the floppy diskette
    controller is reset, and then the fixed disk controller is reset.
    The status returned in AH in this case is the status of the fixed
    disk; to get the status of the floppy diskette controller, examine
    memory location 0040h:0041h.

    If an error is reported by the disk BIOS routines, use this
    service to reset the floppy and/or fixed disk controllers, and
    retry the operation.

    A fixed disk reset is executed only if the value in DL is less
    than or equal to the last fixed disk on the system. That is, the
    lower 7 bits of DL should be less than or equal to the number of
    fixed disks.

    For the AT, XT-286, and PC Convertible, the BIOS executes Int 15h,
    Service 90h (Device Busy), for the diskette (Type = 01h) and the
    fixed disk (Type = 00h) prior to waiting for the interrupt. Int
    15h, Service 91h (Interrupt Complete), is executed upon
    completion. Also diskette operations that require the diskette
    motor to be on will call Int 15h, Service 90 (Device Busy), with
    the type equal to "Diskette Drive Motor Start" (Type = FDh). This
    allows the system to perform another task while the drive motor is
    waiting to get up to speed.