File caching method and apparatus

• US 20030204529A1
• Filed: 04/24/2002
• Published: 10/30/2003
• Est. Priority Date: 04/24/2002
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Hertling, William Edward, Whitmarsh, Michael Dean
• Granted Patent: US 6,944,634 B2
• Time in Patent Office: Days
• US Class Current: 707/200
• CPC Class Codes: G06F 16/9574 of access to content, e.g. by caching
• CPC Class Codes: Y10S 707/99931 Database or file accessing

Abstract

A method of managing data files in a file caching server provides access to a plurality of stored data files. The method is to receive a request for a file, which is identified by a cryptographically secure checksum. The availability of the file is determined using the cryptographically secure checksum and, if said file is available, retrieving the file. If the file is not available to said file caching server, then a file request is issued to, and the file is retrieved from another file server where the file with the cryptographically secure checksum exists.

Claims

1. A method of managing data files in a file caching server that provides access to a plurality of stored data files, said method comprising:

receiving a request for a file, identified by a cryptographically secure checksum;

determining if said file is available to said file caching server using said cryptographically secure checksum and, if said file is available, retrieving said file;

if said file is not available to said file caching server, then requesting from another file server, a remote file having said cryptographically secure checksum.

2. The method of claim 1, comprising:

providing the file in response to the request.

3. The method of claim 1, comprising:

receiving the remote file from the other file server.

4. The method of claim 3, comprising:

providing the remote file in response to the request.

5. The method of claim 1, wherein the request includes a first file name, further comprising:

a string of characters.

12. The method of claim 11 wherein said step of storing a file and a file name on said network data resource includes the step of storing said file and file name on a file caching server.

6. A method of managing data files between a file caching server and a file server, operatively coupled together to provide access to a plurality of stored data files, said method comprising:

receiving at said file server, a request for a file having a file name;

determining if said file name correlates to a cryptographically secure checksum for a data file directly accessible to said file server;

if said first file name correlates to a cryptographically secure file identifier of a file accessible to said file server, then retrieving said file and sending said first file to the file caching server.

7. A method of managing data file storage in a file caching server and a file server, which provide access to a plurality of stored data files, said method comprising:

;

receiving at a file server, a request for a file from a caching server, said file being identified to said file server by a file name;

said file server calculating a cryptographically secure file identifier for said file;

said file server sending said cryptographically secure file identifier for said file to said caching server.

8. The method of claim 7, further including:

sending said file from said file server to said caching server.

9. A method of managing files on a file caching server, comprising:

receiving, at said file caching server, a file save request including a file to be saved on said file caching server and a file name associated with said file under which said file is to be saved;

determining a cryptographically secure checksum from contents of said file;

prior to saving said file, determining if said file is stored on said file caching server by the presence of the cryptographically secure checksum in said file caching server;

if the cryptographically secure checksum is not present in said file caching server, then storing the file, the file name, and the cryptographically secure checksum within the file caching server.

10. The method of claim 9, further comprising:

determining if the cryptographically secure checksum is present on a file server to which said file caching server is operatively coupled

if the cryptographically secure checksum is not present in said file server, then storing the file, the file name, and the cryptographically secure checksum within the file server.

11. A method of storing files on a network data resource that provides access to a plurality of stored data files to a plurality of network users, said method comprised of the steps of:

storing a file and said file name on a network data resource;

calculating a cryptographically-secure file identifier from the contents of said file;

storing said cryptographically-secure file identifier on said network data resource;

locating said file on said network data resource using either of said file name and said file identifier.

13. The method of claim 11 wherein said step of storing a file and a file name on said network data resource includes the step of storing said file and file name on a file server.

14. A data network comprised of:

a file caching server capable of receiving requests for files from client computers operatively coupled to said file caching server, the file caching server identifying requested files by at least one of;

a file name and a cryptographically secure checksum, said file caching server delivering to a client a locally stored copy of the requested file if said requested file is identified as being stored on said file caching server by the presence of said cryptographically secure checksum, and said file caching server delivering to the client a remotely stored copy of the requested file obtained from a file server if said requested file is not identified by said cryptographically secure checksum.

15. A data network comprised of:

a file server capable of storing files from a file caching server operatively coupled to said file server, the file server identifying a file to be stored by a cryptographically secure checksum, said file server storing said file from said file caching server if said file is not identified as being stored on said file sever by the presence in said file server of said cryptographically secure checksum.

16. Data storage media configured to store executable computer program instructions to cause a computer to:

receive a request for a file, which is identified by a cryptographically secure checksum;

determine if said file is available to said computer using said cryptographically secure checksum and, if said file is available, retrieving said file;

if said file is not available to said computer, then requesting from a second computer a remote file having said cryptographically secure checksum.

17. A method of managing the transfer of a plurality of associated data files between a server and a client having a plurality of files to send to said server, said method comprising:

said client calculating a cryptographically secure checksum for at least a first file of said plurality of files;

said client determining if said server has a file with an identical cryptographically secure checksum;

if said server has a file with an identical cryptographically secure checksum, determining that said server has a copy of said first file;

if said server does not have a file with an identical cryptographically secure checksum, sending said first file to said server by said client.

18. The method of claim 17 wherein said plurality of files are print job files.

19. The method of claim 17 wherein said server is an on-line print service provider computer.

20. The method of claim 17 wherein said client is a computer of a customer to an on-line print service provider.

21. The method of claim 17 wherein the step of said client determining if said server has a file with an identical cryptographically secure checksum comprises:

said client transmitting said checksums to said server and receiving from said server an identification of the checksums on the server that do not match checksums received from said client.

22. The method of claim 17 wherein the step of said client determining if said server has a file with an identical cryptographically secure checksum comprises:

said client transmitting said checksums to said server and receiving from said server an identification of the checksums on the server that do match checksums received from said client.

23. A method of managing the transfer of a plurality of associated data files between a server and a client having a plurality of files to send to a server, said method comprising:

said client calculating a checksum for each file of said plurality of files;

said client sending each of said plurality of files to said server;

modifying at least one of said plurality of files;

said client recalculating the checksum for each of said plurality of files;

said client determining which of the files stored on said server have checksums that do not match the recalculated checksums;

said client re-sending to said server, only the files stored on the server whose checksums do not match the recalculated checksums on the client.

24. The method of claim 23 wherein said step of modifying at least one of said plurality of files comprises:

said client modifying said at least one of said files.

25. The method of claim 23 wherein said step of modifying at least one of said plurality of files comprises:

modifying said at least one of said files by a computer other than said client and said server.

26. The method of claim 23 wherein said plurality of files are print job files.

27. The method of claim 23 wherein said server is an on-line print service provider computer.

28. The method of claim 23 wherein said client is a computer of a customer to an on-line print service provider.

29. A method of managing the transfer of a plurality of associated data files between a server and a client having a plurality of files to send to said server, said method comprising:

said server receiving said plurality of files;

said server calculating a checksum for each file and storing the server-calculated checksums in a first list;

said server receiving a second list of client-calculated checksums from said client;

said server identifying to said client, checksums in the second list that are not in the first list;

said server receiving from said client, files whose checksums were not in the second list.

30. The method of claim 29 wherein said files are print job files.

31. The method of claim 29 wherein said step of identifying to said client, checksum in the second list that are not in the first list is comprised of the steps of:

comparing the contents of said first list to the contents of said second list and identifying elements of the second list that are not in the first list.