Storage system storing a file with multiple different formats and method thereof

• US 7,185,030 B2
• Filed: 03/18/2004
• Issued: 02/27/2007
• Est. Priority Date: 03/18/2004
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kodama, Shoji
• Primary Examiner(s): Rimell; Sam
• Assistant Examiner(s): Mahmood; Rezwanul
• Application Number:
  US10/802,852
• Publication Number:
  US 20050210083A1
• Time in Patent Office: 1,076 Days
• Field of Search: 707/10, 707/200, 707/203, 707/204, 707/101, 707/104.1
• US Class Current: 1/1
• CPC Class Codes: G06F 16/10 File systems; File servers
• CPC Class Codes: Y10S 707/99954 Version management

Abstract

A storage system, method and system for storing an original file and at least one format converted file of the original file. The storage system includes a storage medium and a file conversion unit which, in response to a request to store an original file, converts the original file to at least one format converted file. The file conversion unit alternatively could be external of the storage system forming a storage system. The storage system stores the original file and the at least one format converted file on said storage medium and manages a relationship between the original file and the format converted file to permit retrieval of either of the original file and the format converted file.

Claims

1. A storage system for storing an original file and at least one format converted file of the original file comprising:

a storage media; and

a file conversion unit which, in response to a request to store an original file is configured to convert the original file to at least one format converted file,

wherein said storage system is configured to store the original file and the at least one format converted file on said storage media, and is able to manage a relationship between the original file and the at least one format converted file to permit retrieval of either of the original file and the at least one format converted file,

wherein said file conversion unit is configured to calculate a first hash value of the original file and a second hash value for each of the at least one format converted files, and

wherein said storage system is configured by instructions to determine whether the original file has changed or whether the at least one format converted file has changed by reading one of said files, calculating a new hash value for the read file, and comparing said new hash value with a respective one of said first hash value if said original file is read, or comparing the new hash value with a corresponding second hash value if one of said format converted files is read.

2. A storage system according to claim 1, wherein the relationship between the original file and the format converted file is managed by including a first inode that includes the first hash value stored therein, said first inode further including, for each at least one format converted file, an inode number of a second inode that stores the second hash value and that points to a corresponding format converted file.

3. A storage system according to claim 1, wherein said file conversion unit is external of said storage system.

4. A storage system according to claim 1,

wherein said first hash value is used to determine whether the original file has changed by

reading the original file pointed to by a first inode that stores the first hash value,

calculating a first new hash value from the original file as read, and

comparing the, first hash value stored in the first inode with the first new hash value to determine whether the original file has changed;

and

wherein said second hash value is used to determine whether the format converted file has changed by

reading a second inode listed in said first inode for said format converted file,

reading the format converted file pointed to by the second inode,

calculating a second new hash value from the format converted file as read, and

comparing the second hash value stored in the second inode with the second new hash value to determine whether the format converted file has changed.

5. A storage system according to claim 1, wherein a directory list is maintained indicating a corresponding relation between the original file, formats to which the original file has been converted, information based on hash checks indicating whether the original file or the format converted file has changed, and information indicating a status of the change.

6. A storage system according to claim 1, wherein checked hash values of original files and format converted files are used to create a status table of the original files and format converted files, indicating whether the files are changed or unchanged and whether an unchanged format converted file is able to be reconverted to an original file format.

7. A storage system according to claim 1, wherein a file is able to be stored at different locations on said storage media, on other storage media, or on other storage media of a remote storage system which is able to be accessed via a network based on a format of said file or a directory in which files are located.

8. A storage system according to claim 7, wherein storing of a file based on its format is conducted based on a file storing rule.

9. A storage system according to claim 1, wherein a list of formats in which a file is stored is able to be obtained.

10. A method of storing an original file and at least one format converted file of the original file in a storage system which includes a storage media, said method comprising the steps of:

in response to a request to store an original file, converting the original file to at least one format converted file;

storing the original file and the at least one format converted file on the storage media;

managing a relationship between the original file and the format converted file to permit retrieval of either of the original file and the format converted file using an original inode that points to the original file, and by including in said original inode, for each said at least one format converted file, an inode number of a secondary inode corresponding to each said at least one format converted file;

calculating a first hash value for the original file and storing said first hash value in said original inode;

calculating a second hash value for each said at least one format converted file and storing each second hash value in the secondary inode corresponding to that format converted file; and

using said first hash value to determine whether the original file has changed and/or using said second hash value to determine whether the corresponding format converted file has changed.

11. A method according to claim 10, wherein said storage system determines whether the original file has changed or whether the format converted file has changed by reading a file pointed to by said first inode or said second inode, respectively, calculating a new hash value for the read file, and comparing said new hash value with a respective one of said first hash value or said second hash value.

12. A method according to claim 10, wherein a file conversion unit performs the converting and said file conversion unit is external of said storage system.

13. A method according to claim 10, wherein a file conversion unit performs the converting and said file conversion unit calculates the first hash value of the original file and the second hash value of the format converted file, and

wherein said first hash value is used to determine whether the original file has changed by

reading the original file pointed to by a first inode that stores the first hash value,

calculating a first new hash value from the original file as read, and

comparing the first hash value stored in the first inode with the first new hash value to determine whether the original file has changed;

and

wherein said second hash value is used to determine whether the format converted file has changed by

reading a second inode listed in said first inode for said format converted file,

reading the format converted file pointed to by the second inode,

calculating a second new hash value from the format converted file as read, and

comparing the second hash value stored in the second inode with the second new hash value to determine whether the format converted file has changed.

14. A method according to claim 10, wherein a directory list is maintained indicating a corresponding relation between the original file, formats to which the original file has been converted, information based on hash checks indicating whether the original file or the format converted file has changed, and information indicating a status of the change.

15. A method according to claim 10, wherein checked hash values of original files and format converted files are used to create a status table of the original files and format converted files, indicating whether the files are changed or unchanged and whether an unchanged format converted file is able to be reconverted to an original file format.

16. A method according to claim 10, wherein a file is able to be stored at different locations on said storage media or on other storage media based on a format of said file.

17. A method according to claim 16, wherein storing of a file based on its format is conducted based on a file storing rule.

18. A method according to claim 10, wherein a list of formats in which a file is stored is able to be obtained.

19. A system comprising:

a storage system which includes a storage media for storing files; and

a file conversion unit, which is connected to said storage system and which in response to a request to store an original file, is configured to convert the original file to at least one format converted file,

wherein said storage system stores the original file and the at least one format converted file on said storage media and manage a relationship between the original file and the format converted file to permit retrieval of either of the original file and the at least one format converted file by storing in a first inode a pointer to said original file and an inode number of a second inode, said second inode pointing to a corresponding format converted file,

wherein said file conversion unit is configured to calculate a first hash value of the original file and, for each at least one format converted file, a second hash value corresponding to the format converted file, and

wherein said first hash value is stored in said first inode, and is used to determine whether the original file has changed, and

wherein each said second hash value is stored in the corresponding second inode, and is used to determine whether the corresponding format converted file has changed.

20. A system according to claim 19, wherein said storage system determines whether the original file has changed or whether the format converted file has changed by reading a file pointed to by said first inode or said second inode, respectively, calculating a new hash value for the read file, and comparing said new hash value with a respective one of said first hash value or said second hash value.

21. A system according to claim 19, wherein said file conversion unit is external of said storage system.

22. A system according to claim 19, wherein said file conversion unit calculates a first hash value of the original file which is stored with said first inode and a second hash value of the format converted file which is stored with said second inode, and

wherein said first hash value is used to determine whether the original file has changed by

reading the original file pointed to by the first inode that stores the first hash value,

calculating a first new hash value from the original file as read, and

comparing the first hash value stored with the first inode with the first new hash value to determine whether the original file has changed;

and

wherein said second hash value is used to determine whether the format converted file has changed by

reading the second inode whose inode number was stored in said first inode for said format converted file,

reading the format converted file pointed to by the second inode,

calculating a second new hash value from the format converted file as read, and

comparing the second hash value stored with the second inode with the second new hash value to determine whether the converted format file has changed.

23. A system according to claim 19, wherein a directory list is maintained indicating a corresponding relation between the original file, formats to which the original file has been converted, information based on hash checks indicating whether the original file or the format converted file has changed, and information indicating a status of the change.

24. A system according to claim 19, wherein checked hash values of original files and format converted files are used to create a status table of the original files and format converted files, indicating whether the files are changed or unchanged and whether an unchanged format converted file is able to be reconverted to an original file format.

25. A system according to claim 19, wherein a file is able to be stored at different locations on said storage media or on other storage media based on a format of said file.

26. A system according to claim 25, wherein storing of a file based on its format is conducted based on a file storing rule.

27. A storage system according to claim 19, wherein a list of formats in which a file is stored is able to be obtained.