Patent ID: 8051041

Claim:
A file difference management apparatus comprising: a storage unit in which a group data table and a difference detection data table are stored; a difference data detection module configured to search a previous difference detection file which is an original file of an difference management object file and detect a difference between said previous difference detection file and said difference management object file; and a difference data management module configured to record a difference detection data used to detect the difference on said difference detection data table, wherein said difference data detection module: selects a group to which said difference management object file belongs, based on a group condition registered on said group data table, the group including a plurality of object files including said difference management object file, the group specified by at least a date and time in which said object files have been generated, such that said object files are not specified a priori by filename, where a first type of processing is specified, extracts the difference detection data related to said group from said difference detection table without comparing the extracted difference detection data and a file data of said difference management object file, where a second type of processing is specified, extracts the difference detection data related to said group from said difference detection table by locating difference extraction start data within said difference object file and extracting the difference detection data starting at the difference extraction start data, detects the difference between said difference management object file and said previous difference detection file, based on a comparing result of the extracted difference detection data and the file data of said difference management object file, and said difference data management module records a set of said file data and said group as a new difference detection data on said difference detection data table, when the difference is detected, wherein data necessary for a next difference detection operation is stored in said difference detection table, and wherein a filename of each object file in the group is dynamic, and includes the date and time at which said object file has been generated.