Patent ID: 7549031

Claim:
A method for performing a backup and restore job of an entire or a portion of data, which is a subject for a backup storage of the data, to a storage medium by a computer, comprising steps of: storing management information having a correspondence relationship between a portion of the data and an identification information of the backup job when the portion of the data has been copied to the medium, by the computer; acquiring the identification information of the backup job by the computer, including a version number, and storing the version number in a version number storage unit; identifying a portion of the data, which has not been copied to the media during a predetermined period, based upon the identification information of the backup job; determining whether to backup the portion of the data to the medium, by the computer; calculating the version number of a backup job by subtracting a predetermined expiration period from the version number of the current backup job; backing up the portion of the data by copying the portion of the data to the medium by the computer; and restoring the portion of the data from the medium by the computer by the steps of: acquiring a latest version number from the version number storage unit; acquiring the predetermined expiration period for backed-up data; determining a version number for restoration by subtracting the predetermined expiration period from the latest version number; and reading the portion of the data from the medium by the computer.