Patent ID: 7249119

Claim:
A storage system, comprising: a client that issues a file write request or a file read request; an archive server that is connected to the client via a network, and processes the request issued from the client; a storage device that is connected to the archive server, and records files; and a disk drive connected to the client, wherein: the client comprises at least one client process and an archive client library; the client process sends a first file read request containing at least one of a first file identifier and a combination of a first file name and an archived date to the archive server; the archive server: when the archive server receives the first file read request sent from the client process, referring to a file information table stored beforehand in the archive server, identifies the first file, based on the at least one of the file identifier and the combination of the first file name and the archived date contained in the first file read request, obtains the identified first file from the storage device, and sends the obtained first file to the client process; the archive client library: extracts a file archived date from the first file sent from the archive server, obtains a process identifier of the client process that requested the first file; stores in the disk drive a combination of the extracted archived date and the obtained process identifier, in an archived date management table for processes; when the archive client library receives a second file read request containing a second file name of a second file relating to the first file obtained from the archive server, obtains an archived date stored in the archived date management table for processes, appends the obtained archived date to the second file read request, and sends the second file read request to the archive server; and the archive server: when the archive server receives the second file read request sent from the client process, obtains the second file name and the archived date from the second file read request, identifies a latest archived file having the obtained second file name that was recorded before the obtained archived date, from among the files recorded in the storage device, referring the file information table recorded in the archive server, obtains the identified second file from the storage device, and sends the obtained second file to the client process.