Zymbolic history management system

• US 5,706,510 A
• Filed: 03/15/1996
• Issued: 01/06/1998
• Est. Priority Date: 03/15/1996
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Burgoon, David A.
• Primary Examiner(s): Kulik, Paul V.
• Application Number:
  US08/617,989
• Time in Patent Office: 662 Days
• Field of Search: 395/619, 395/701-703, 395/712, 395/601, 395/608, 395/617, 395/772
• 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 zymbolic history management system (ZHMS) allows a user to create annotated symbolic links (zymlinks) to files in a shared file system. A single link is created to each file of the shared file system which a user wishes to access. A zymlink to the shared file system may be updated via a zupdate command. Rather than selectively updateing individual files, a user simply zupdate'"'"'s whole trees of files. When it comes time to edit files, a user makes use of standard history managed file system commands to obtain a writable copy of a file. Use of one of these commands destroys a zymlink corresponding to the file, and substitutes a privately owned copy of the file on a user'"'"'s disk. When the edited file is checked back into the history managed file system, a read-only copy of the file remains on a user'"'"'s disk. When a user updates his or her file system, the read-only file copy may be replaced with a new zymlink. A user will normally view current versions of shared files. Rather than viewing current versions of shared files, a user may wish to maintain a static view of file versions by issuing a zreset command. The system provides a user with more free disk space than in conventional history managed systems.

Claims

1. A computer implemented method for allowing a user to access a plurality of files stored in one or more computer accessible storage medias, and more specifically, a method for allowing a user to access specific versions of the plurality of files, the method comprising:

a) constructing a plurality of file versions to be stored within a shared file system, said file versions being constructed from a plurality of file revision archives stored in a history managed file system, said shared and history managed file systems being logically separate from one another;

b) providing a plurality of user file systems with read-only access to the shared file system, said plurality of user file systems being logically separate from both the shared file system, the history managed file system, and each other, and said plurality of user file systems already having read/write access to the history managed file system;

c) mapping directory hierarchies of the plurality of user file systems into directory hierarchies of the shared file system;

d) creating a plurality of files under the directory hierarchies of a user file system wherein each of the created files is a symbolic link corresponding to a file version comprising the shared file system, said correspondence of symbolic links and file versions being based on the mappings of directory hierarchies;

e) creating first revision information files, said first revision information files being derived from said file revision archives, each first revision information file comprising file revision information corresponding to the file versions of one or more directories of the shared file system'"'"'s directory hierarchies; and

f) creating second revision information files, said second revision information files being initially derived from said first revision information files, each second revision information file comprising file revision information corresponding to the symbolic links of one or more of a user file system'"'"'s directory hierarchies.

2. A method as in claim 1, further comprising the steps of:

a) destroying a symbolic link when one of the plurality of user file systems requires a writable copy of a file; and

b) replacing said destroyed symbolic link with a proprietary copy of a file obtained from one of the plurality of file revision archives, said writable copy of the file possibly comprising a file version which differs from the file version with which the destroyed symbolic link corresponded.

3. A method as in claim 2, further comprising the step of updating the plurality of file versions and first revision information files of the shared file system.

4. A method as in claim 3, wherein the step of updating the shared file system comprises issuing a zrevfupdate command.

5. A method as in claim 3, further comprising the step of updating the symbolic links of a user file system.

6. A method as in claim 5, wherein the step of updating the symbolic links in a user file system comprises:

a) replacing, if possible, a proprietary copy of a file in the user file system with a new symbolic link to a version of the proprietary file comprising the second file system; and

b) updating file revision information in second revision information files corresponding to the updated symbolic links.

7. A method as in claim 6, wherein the step of updating the symbolic links of a user file system comprises issuing a zupdate command.

8. A method as in claim 3, further comprising the step of resetting the symbolic links of a user file system in order to circumvent an update to the shared file system.

9. A method as in claim 8, wherein the step of resetting the symbolic links of a user file system comprises:

a) acknowledging, from the standpoint of a user file system, that the shared file system has been updated; and

b) obtaining for the user file system, a read-only proprietary version of a file version which no longer exists as part of the shared file system.

10. A method as in claim 9, wherein the step of resetting the symbolic links of a user file system comprises issuing a zreset command.

11. A system stored in one or more computer readable storage medias for allowing a user to access a plurality of files, and more particularly, specific versions of the plurality of files, the system comprising:

a) a shared file system, and a plurality of user file systems, all of said file systems being physically stored within the one or more computer readable storage medias as logically separate file systems,

i) said shared file system employing read-only access to a number of file revision archives stored in a history managed file system which is logically separate from said shared and plurality of user file systems, said shared file system comprising,

A) a plurality of file versions, organized in directory hierarchies and derived from said file revision archives; and

B) first revision information files, also derived from said file revision archives, each first revision information file comprising file revision information corresponding to the file versions of one or more directories of the shared file system'"'"'s directory hierarchies;

ii) said plurality of user file systems having read-only access to said plurality of file versions, and read/write access to said file revision archives;

b) a number of map entries, the number of map entries indicating which directory hierarchies comprising any of said plurality of user file systems correspond with the directory hierarchies of the shared file system;

c) a plurality of symbolic links stored as files in the directory hierarchies comprising any of the plurality of user file systems, each of said symbolic links corresponding to a file version comprising the shared file system, said correspondence of symbolic links and file versions being based on the number of map entries; and

d) second revision information files, initially derived from said first revision information files, each second revision information file comprising file revision information corresponding to the symbolic links of one or more of a user file system'"'"'s directory hierarchies.

12. A system as in claim 11, further comprising:

a) means for each of the plurality of user file systems to simultaneous read, via its symbolic links, the file versions comprising said second file system; and

b) means for each of the plurality of user file systems to obtain its own proprietary version of a file from said file revision archives.

13. A system as in claim 12, wherein the means for each of the plurality of user file systems to obtain its own proprietary version of a file from said file revision archives comprises means to destroy a symbolic link and replace it with a proprietary file version which may or may not be identical to the file version which was previously accessible via the symbolic link.

14. A system as in claim 13, further comprising:

a) means to update the plurality of file versions and first revision information files of the shared file system, said means being responsive to updates checked into the file revision archives;

b) means to update the symbolic links between a user file system and the shared file system, said means being independent of said means for updating the shared file system; and

c) means to reset the symbolic links of a user file system in order to circumvent an update to the shared file system.

15. A system as in claim 14, wherein said means for updating the shared file system comprises a zrevfupdate command.

16. A system as in claim 14, wherein said means for updating symbolic links comprises:

a) means to replace, if possible, a proprietary version of a file with a new symbolic link to a version of the proprietary file comprising the second file system; and

b) means to update file revision information in a second revision information file corresponding to an updated symbolic link.

17. A system as in claim 16, wherein said means for updating symbolic links comprises a zupdate command.

18. A system as in claim 14, wherein said means for resetting symbolic links comprises:

a) means for a user file system to acknowledge an update to the shared file system; and

b) means for a user file system to obtain a read-only proprietary version of a file version which no longer exists as part of the shared file system.

19. A system as in claim 18, wherein said means for resetting symbolic links comprises a zreset command.

20. A system as in claim 11, wherein:

a) said file systems exist as a network of servers and clients;

b) said shared and plurality of user file systems exist as clients of a first server servicing the file revision archives of a history managed file system;

c) said shared file system exists as a second server; and

d) said plurality of user file systems exist as clients of said second server.