PURPOSE: To simplify an operation and to shorten restoration time by previously managing information required for restoration work when a disk fault occurs during a job processing.

CONSTITUTION: Control information required for operating a medium restoration processing for restoration-processing a fault disk and a file restoration processing is stored in a restoration information management file 1 when a medium is saved. When a medium fault occurs, the display of restoration information is requested from an operator to a medium restoration information management system 7. When the display of restoration information is requested, a saving medium control part 5 is started from a restoration information display part 3 and a saving medium name for the medium being the object of restoration is retrieved. A file restoration information control part 4 is started at the same time as the starting of the saving medium control part 5, and file restoration information for the medium being the object of restoration is retrieved. The restoration information display part 3 displays information which is obtained last to the operator. Thus, the accuracy of the restoration processing when the medium fault occurs can be improved and efficiency can be improved.