Int 21 Fn 4401  - DOS 2+ - Ioctl - Set Device Information                  [D]

   AX = 4401h
   BX = handle (must refer to character device)
   DX = device information word (see AX=4400h)
       (DH must be zero)

Return: CF clear if successful
   CF set on error
       AX = error code (01h,05h,06h,0Dh) (see AH=59h)

See Also: AX=4400h,INT 2F/AX=122Bh