Int 6F Fn 11 - 10net - Lock Fcb [N] AH = 11h AL = mode 01h sequential 02h random 03h random block CX = number of records DS:DX -> FCB (see INT 21/AH=0Fh) Return: CF clear if successful CF set on error AX = error code (see also AH=00h) 0002h file not found See Also: AH=12h