Patent ID: 8423556

Claim:
An archive device comprising: a storage to store divided data and attribute information, the divided data being received from an external device and divided from original data by a predetermined size, the attribute information being associated with a hash value and identification information, the hash value being calculated from the divided data, the identification information identifying the original data before being divided; and a processor to calculate a hash value for the divided data that is received from the external device, write the divided data and the attribute information corresponding to the divided data to the storage when the calculated hash value for the divided data does not match the hash value included in the attribute information stored in the storage, and add the identification information corresponding to the calculated hash value to the attribute information when the calculated hash value matches the hash value included in the attribute information stored in the storage, the processor writes information indicating that a plurality of the original data includes a plurality of common divided data, respectively, the processor combines the plurality of common divided data and stores a hash value calculated from the combined divided data in the storage if a number of the original data including the plurality of common divided data is not less than a predetermined value.