File storage system and a NAS server

• US 7,206,939 B2
• Filed: 05/30/2002
• Issued: 04/17/2007
• Est. Priority Date: 03/26/2002
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Itoh, Shinji, Miyazaki, Kunihiko, Bessho, Yoshiharu, Omoto, Narihiro
• Primary Examiner(s): Zand; Kambiz
• Assistant Examiner(s): Lanier; Benjamin E.
• Application Number:
  US10/157,042
• Publication Number:
  US 20030187885A1
• Time in Patent Office: 1,783 Days
• Field of Search: 713/178
• US Class Current: 713/193
• CPC Class Codes: G06F 16/10 File systems; File servers

Abstract

A reliably safe storage system is provided which makes provable the status of a file stored in a storage server at a time specified by a user and creates evidence information that will be effective in future. In response to a file status fixing request from the user over a network, a storage server generates file fixing guarantee data, including data publicized by a publication server, and saves the generated data with the file associated with the generated data.

Claims

1. A file storage system comprising at least one user computer, a storage server connected to said user computer over a network for storing files, and a condense server connected to at least said storage server via the network for generating file fixing guarantee data,

(A) said storage server comprising:

means for accepting a request for fixing a file status from said at least one user computer;

means for generating a request for guaranteeing file fixing in response to said file status fixing request, said file fixing guarantee request being to request file fixing guarantee data for proving a status of the file managed by said storage server at the time of the fixing request to a third party;

means for sending said file status fixing guarantee request to said condense server;

means for accepting file status fixing guarantee data generated by said condense server in response to said file status fixing guarantee request, said file status fixing guarantee data guaranteeing the status of a fixed file; and

means for storing said accepted file status fixing guarantee data so as to associate with said file;

(B) said condense server comprising;

means for receiving said file status fixing guarantee request, from said storage server;

means for generating said file status fixing guarantee data based on said file status fixing guarantee request; and

means for sending said generated file status fixing guarantee data to said storage server.

2. The file storage system according to claim 1,

further comprising a publication server which publicizes digital data as validity-guaranteed data,

wherein said file status fixing guarantee data includes the validity-guaranteed data publicized by said publication server.

3. The file storage system of claim 1, wherein said storage server comprises:

first means for generating and storing each of the files with alteration preventing information attached, the alteration preventing information being generated based on the file stored previously to form a chain of generations of the file; and

a second means for publicizing a latest generation of the file at a specified time.

4. The file storage system according to claim 3, wherein

said first means adds a hysteresis signature to the file stored previously to generate the alteration preventing information.

5. The file storage system according to claim 3, further comprising a publication server connected to said storage server over the network wherein said publication server, in response to the publication by the storage server, receives the latest file from the storage server for publication.

6. The file storage system according to claim 1, wherein

said storage server sends the file fixing guarantee data, which is sent from said condense server, to said user computer, which includes means for storing the data, to verify the file on the user computer based on the file fixing guarantee data.

7. A network attached storage (NAS) server connected to the at least one user computer over a network for storing files, wherein said NAS server is configured as the storage server in the file storage system according to claim 1.

10. The file storage system according to claim 1, wherein said file status fixing guarantee data for said file to which a status fixing request is made includes a digital signature of said condense server which said condense server generates in response to said file status fixing guarantee request for said file.

8. A file storage method in a storage server connected to at least one client computer and to a condense server over a network and including a storage, said method comprising:

accepting a request for fixing a file status from said at least one client computer;

in response to the file status fixing request from said client computer, generating a request for guaranteeing file fixing, the file fixing guarantee request being to request file fixing guarantee data for proving to a third party a status of the file at the file fixing request time;

sending the file fixing guarantee request to the condense server for generation of file status fixing guarantee data based on the file status fixing guarantee request;

receiving the generated file status fixing guarantee data from the condense server at the storage server; and

storing the generated file fixing guarantee data in said storage of the storage server, said file fixing guarantee data being correlated with the file.

9. A product comprising a computer readable medium and a computer-executable program embodied in said medium for implementing using a computer, a file storage method in a storage server connected to at least one client computer and to a condense server over a network and including a storage, said method comprising the steps, by said storage server, of:

in response to a file status fixing request received from said client computer, generating a request for guaranteeing file fixing, the file fixing guarantee request being to request file fixing guarantee data for proving to a third party a status of the file at the time of the file fixing request;

sending the file fixing guarantee request to the condense server for generation of file status fixing guarantee data based on the file status fixing guarantee request;

receiving the generated file fixing guarantee data from the condense server; and

storing the generated file fixing guarantee data in said storage of the storage server, said file fixing guarantee data being correlated with the file.