PURPOSE: To effectively use an area on a medium by updating a final data address in a label, writing the label into an unwritten area on the VTOC area and completing the recovery of a file for the file whose data writing processing is stopped by the trouble of a system, etc.

CONSTITUTION: A job A decides the completion of output processing to a file 5 and stops the processing when it is informed that the output processing to the file 5 is abnormally terminated. When a final data address updating means 8 receives the close processing request of the file 5, it stores a final data address 4' transmitted from a data output processing means 7 in a label 4, writes the label 4 into the unwritten area on a VTOC area 3 on a unrewritable medium 2 and thus, terminates the recovery processing of the file 5. Thus, by only executing the same job again, the file can be recovered without wasting the area on the medium.