Int 13h, 17h            Set DASD Type for Format                         many

    This service sets the type of diskette for a particular type of
    drive in order that the disk is properly formatted. This service
    can be performed on diskettes only.

        Entry   AH = 17h
                AL = Diskette/drive combination (see below)
                DL = Drive number (bit 7 must be clear)

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

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                Diskette/Drive Combination
                AL      Meaning
                01h     Diskette 320/360K in 360K drive
                02h     Diskette 360K in 1.2M drive
                03h     Diskette 1.2M in 1.2M drive
                04h     Diskette 720K in 720K drive

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    This service is not available for PCs, PCjrs, and XTs dated before
    1/10/86.

    A diskette/drive combination value of 04h is not valid for ATs
    before 6/10/85.

    For the AT, XT-286, and PC Convertible, the BIOS executes Int 15h,
    Service 90h (Device Busy), for the diskette (Type = 01h) prior to
    waiting for the interrupt. Int 15h, Service 91h (Interrupt
    Complete), is executed upon completion. 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.