Dynamic information format conversion

• US 6,549,918 B1
• Filed: 09/21/1998
• Issued: 04/15/2003
• Est. Priority Date: 09/21/1998
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Liu, Chao-chia, Probert, David Bradley Jr.
• Primary Examiner(s): Rones, Charles
• Application Number:
  US09/157,698
• Time in Patent Office: 1,667 Days
• Field of Search: 360/49, 707/1, 707/10, 707/203, 709/301, 709/232, 709/206, 395/200.33
• US Class Current: 1/1
• CPC Class Codes: G06F 16/258 Data format conversion from or to a database
• CPC Class Codes: Y10S 707/99932 Access augmentation or optimizing
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99954 Version management

Abstract

A software layer (filter driver) residing between software components or application programs running locally or on a client across a network and a persistent store of an operating system provides on-the-fly conversions of persistent information formats. The filter driver determines which format a program expects, and dynamically converts the information from its storage format to the format expected by the program. Conversion includes both data format conversion, and conversion of access semantics. Loadable conversion modules are provided for converting application specific formats due to the potential large number of such formats which can be encountered. The filter driver may change the format that information is stored in based on access history or other system requirements. The software components or application programs may be ignorant of the true storage format used by the system, and thus the filter driver can be used to transparently give old versions of software access to information stored in newer formats.

Claims

1. In a computer system having an application program, a data storage system, and a filter driver residing outside of the application program and operable for converting file formats, a method of providing the application program access in a first format portions of files stored in the data storage system in a second format, the method comprising:

intercepting at the filter driver a request sent by the program to access in the first format portions of a file stored in the data storage system in the second format, the requested portions of the file comprising less than the entire file;

retrieving the requested portions of the file;

invoking in the filter driver a conversion module selected from a plurality of conversion modules to convert the requested portions of the file from the second format to the first format; and

providing the application program access to the requested portions of the file in the first format.

2. The method of claim 1 wherein one of the first and second formats is a single stream structured storage format and the other format is a multi stream structured storage.

3. The method of claim 1 further comprising changing one of the portions of the file converted to the first format and converting the changed portion of information back to the second format.

4. The method of claim 1 further comprising creating an intermediate format to encapsulate a format and semantic difference between the first and second formats.

5. The method of claim 4 wherein the intermediate format includes persisted cached information for use during a subsequent format change.

6. In a standalone or networked computer system having at least a data storage system, a program for accessing files stored in the data storage system, and a filter driver residing outside the program for converting file formats, a method of accessing in a desired format portions of files stored in the data storage system in formats different than desired by the program, the method comprising:

intercepting at the filter driver a request sent by the program to access in a first format portions of a file stored in a second format in the data storage system, the portions of the file comprising less than the entire file;

retrieving the requested portions of the file stored in the second format;

invoking in the filter driver a loadable conversion module selected from a plurality of conversion modules to convert the portions of the file stored in the second format to the first format; and

providing a view of the requested portions of the file from the conversion module such that the portions of the file stored in the second format can be accessed as though they were stored in the first format.

7. The method of claim 6 wherein the filter driver resides in the operating system and wherein the act of invoking further comprises loading the conversion module from an operating system.

8. The method of claim 6 further comprising changing one of the portions of the file converted to the first format and converting the changed portion of information back to the second format.

9. The method of claim 6 wherein the loadable conversion module is selected based on the first format and the second format.

10. The method of claim 6 further comprising creating an intermediate format to encapsulate a format and semantic difference between the first and second formats.

11. The method of claim 10 wherein the intermediate format includes persisted cached information for use during a subsequent format change.

12. The method of claim 6 wherein one of the first and second formats is a single stream structured storage format and the other format is a multi stream structured storage.

13. The method of claim 6, further comprising concurrently providing a view of the requested portions the file in the second format.

14. The method of claim 13 wherein the method is performed by instructions stored on a computer readable medium.

15. The method of claim 14 wherein the instructions are part of a kernel of an operating system on a computer.

16. The method of claim 6 wherein the filter driver resides in the operating system, and the act of invoking further comprises loading the conversion module from the program.

17. The method of claim 6 wherein one of the first and second formats is a format according to one operating system and the other is a format according a different operating system.

18. The method of claim 6 wherein one of the first and second formats is a format according to one version of the program and the other is a format according to a different version of the program.

19. The method of claim 6 wherein one of the first and second formats is a format according to one program and the other is a format according to a different program.

20. The method of claim 19 wherein one of the two programs is tag-based and the other is not tag-based.

21. The method of claim 19 wherein one of the two programs is a data processing program adhering to a data processing protocol and the other program is another data processing program adhering to a different data processing protocol.

22. The method of claim 21 wherein the data processing protocol is an image processing protocol.

23. The method of claim 21 wherein the data processing protocol is a sound processing protocol.

24. In a standalone or networked computer system having at least a data storage system, a program for accessing in a desired format a file stored in the data storage system, and a filter driver that resides outside the program and converts the format of the file to the format desired by the program, a machine readable medium having instructions stored thereon for causing a computer to perform a method of accessing in the desired format the file in a different format than desired, the method comprising:

receiving at the filter driver a request sent by the program to access in a first format portions of the file stored in a second format in the data storage system, the portions of the file comprising less than the entire file;

retrieving the portions of the file stored in the second format;

invoking in the filter driver a loadable conversion module selected from a plurality of conversion modules to convert requested portions of the file to the first format; and

providing a view of the requested portions of the file from the conversion module such that the portions of the file stored in the second format can be accessed as though they were stored in the first format.

25. The medium of claim 24 further comprising instructions for causing the filter driver to invoke the loadable conversion module.

26. The medium of claim 24 further comprising instructions for causing the filter driver to maintain semantics of the second format.

27. The medium of claim 24 wherein one of the first and second formats is a single stream structured format and the other format is a multi stream structured format.

28. In a standalone or networked computer system having at least a data storage system, a program for accessing in a desired format data stored in a binary data files in the data storage system, and a filter driver that resides outside the program for converting the format of the data stored in the binary data file to the format desired by the program, a method of accessing in the desired format portions of a binary data file stored in a different format than desired in comprising:

receiving at the filter driver a request sent by the program to access in a first format portions of the binary data file stored in a second format, the portions of the binary data file comprising less than the entire binary data file;

retrieving the requested portions of the binary data file stored in the second format;

invoking in the filter driver a loadable conversion module selected from a plurality of conversion modules to convert the requested portions of the binary data file to the first format, the loadable conversion module being selected based on the first format and the second format;

providing a view of the requested portions of the binary data file from the conversion module such that the portions of the binary data file stored in the second format can be accessed as though they were stored in the first format; and

changing one of the portions of the binary data file converted to the first format and converting the changed portion of information back to the second format.