INT 21 - DOS 2+ - IOCTL - SET DEVICE INFORMATION AX = 4401h BX = handle (must refer to character device) DX = device information word (see #01423) (DH must be zero for DOS version prior to 6.x) Return: CF clear if successful CF set on error AX = error code (01h,05h,06h,0Dh) (see #01680 at AH=59h/BX=0000h) Note: this function was not supported by Digital Research's DOS Plus SeeAlso: AX=4400h,INT 2F/AX=122Bh