Patent ID: 8660998

Claim:
A duplicate file detection device comprising: a storage unit that stores information defining data used for calculating hash values of files for each extension of the files; a calculation unit that acquires information corresponding to extensions of each of a plurality of files to be examined from the storage unit and uses the acquired information to calculate hash values of each of the plurality of files to be examined; and a detection unit that detects duplicated files by comparing the hash values of each of the plurality of files to be examined that are calculated by the calculation unit; and a mediation unit that receives an examination request containing information regarding the file servers that hold the plurality of files to be examined from an external device and sends the received examination request to the calculation unit, wherein said data used for calculating said hash values is set for said each extension of the files in advance, wherein the storage unit stores information comprising a complete version of a file as information used when a data size of said file does not exceed a threshold value and stores information defined as a specific portion of a file as information used when the data size of said file exceeds the threshold value, wherein the calculation unit acquires the plurality of files to be examined from the file servers identified in the examination request and calculates hash values for each of the acquired plurality of files, wherein the detection unit, upon detection of duplicated files, sends the detection results to the mediation unit, and wherein the mediation unit transmits examination results containing the detection results sent from the detection unit to the external device.