INT 2F - SMARTDRV v4.00+ - GET DEVICE DRIVER FOR DRIVE
        AX = 4A10h
        BX = 0007h
        BP = drive number
Return: DL = ???
        ES:DI -> device driver header for drive
Note:   this function is also supported by PC-Cache v8.0.
SeeAlso: AX=4A10h/BX=0000h,AX=4A11h/BX=0003h,AX=4A11h/BX=0004h

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