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