File system conversion

• US 6,377,958 B1
• Filed: 07/07/2000
• Issued: 04/23/2002
• Est. Priority Date: 07/15/1998
• Status: Expired due to Term

• Current Assignee: Veritas Technologies, LLC (Whitehouse Group Ltd.)
• Original Assignee: Powerquest Corporation (NortonLifeLock Inc.)
• Inventors: Orcutt, Niel
• Primary Examiner(s): Alam, Hosain T.
• Assistant Examiner(s): Kindred, Alford W.
• Application Number:
  US09/612,581
• Time in Patent Office: 655 Days
• Field of Search: 707/200-206, 707/100-102, 707/7, 711/100, 711/129, 711/130-132, 711/173, 711/208
• US Class Current: 707/690
• CPC Class Codes: G06F 16/116 Details of conversion of file system types or formats

Abstract

Methods and systems are provided for converting from a complex file system such as a Microsoft NTFS file system or a Linux ext2fs file system, to a simpler FAT file system. Features of the advanced file system are identified and handled. Depending on the circumstances, some features are carried over to the resulting FAT file system, while other features carry over only partially or not at all.

Claims

1. A method for converting an advanced file system to a simpler file system in-place while preserving user data, the method comprising the steps of:

checking for sufficient space to hold file system structures of the simpler file system;

creating file system structures of the simpler file system using data values from file system structures of the advanced file system; and

updating file system identification information to identify the simpler file system to an operating system rather than identifying the advanced file system to the operating system.

2. The method of claim 1, wherein the creating step creates file system structures of-the simpler file system in part of a partitionable storage medium that is treated by the advanced file system as free space.

3. The method of claim 1, wherein the method further comprises vacating space, and the creating step creates file system structures of the simpler file system at least partially in such vacated space.

4. The method of claim 1, wherein the method comprises deleting at least one advanced file system feature without user permission, such that the simpler file system produced by the method lacks a feature corresponding to the deleted feature.

5. The method of claim 1, wherein the method comprises deleting at least one advanced file system feature after obtaining user permission, such that the simpler file system produced by the method lacks a feature corresponding to the deleted feature.

6. The method of claim 1, wherein the advanced file system includes a file that has a short file name and lacks a long file name, and the method comprises creating a FAT long file name corresponding to the short file name.

7. The method of claim 1, wherein the advanced file system includes a first volume label that contains more than eleven characters, and the method comprises creating from the first volume label a FAT volume label of no more than eleven characters.

8. The method of claim 1, wherein the advanced file system includes at least one NTFS index, and the method comprises deleting that index such that no corresponding index appears in a FAT file system produced by the method.

9. The method of claim 1, wherein the advanced file system includes at least one NTFS named data stream, and the method comprises deleting that named data stream such that no corresponding data appears in a FAT file system produced by the method.

10. The method of claim 1, wherein the advanced file system includes at least one NTFS named data stream, and the method comprises saving the data of that named data stream so it appears in a file in a FAT file system produced by the method.

11. The method of claim 1, wherein the advanced file system includes at least one NTFS file having two or more versions, and the method comprises deleting all but one of the versions so that only one version appears in a FAT file system produced by the method.

12. The method of claim 1, wherein the advanced file system includes at least one NTFS file having two or more versions, and the method comprises saving the data from each of at least two of the versions so that each version'"'"'s data appears in a FAT file system produced by the method.

13. The method of claim 1, wherein the advanced file system includes at least one access control list restricting access to a file, and the method comprises deleting that access control list such that no corresponding access restrictions appear in a FAT file system produced by the method.

14. The method of claim 1, wherein the advanced file system includes at least one NTFS user storage quota for a file, and the method comprises deleting that storage quota such that no corresponding storage restriction appears in a FAT file system produced by the method.

15. A computer storage medium having a configuration that represents data and instructions which will cause performance of the method steps in claim 1.

16. A method for at least attempting conversion of an advanced file system to a simpler file system, the method comprising the steps of:

checking for at least one preventive condition in the advanced file system that prevents an implementing program from completing a file system conversion from the advanced file system to the simpler file system;

discontinuing an attempted file system conversion by the implementing program without completing the file system conversion if such a preventive condition is found; and

completing the file system conversion if no such preventive condition is found, wherein completing the conversion comprises creating file system structures of the simpler file system using data values from file system structures of the advanced file system and updating file system identification information to identify the simpler file system to an operating system rather than identifying the advanced file system to the operating system.

17. The method of claim 16, wherein the condition checking step checks for the following preventive condition:

a lack of sufficient space to hold file system structures of the simpler file system.

18. The method of claim 16, wherein the condition checking step checks for the following preventive condition:

files compressed by a file system driver.

19. The method of claim 16, wherein the condition checking step checks for the following preventive condition:

sparse files.

20. The method of claim 16, wherein the condition checking step checks for the following preventive condition:

a file with more than one short name and one long name, both in the same directory.

21. The method of claim 16, wherein the condition checking step checks for the following preventive condition:

clusters which are at least sixty-four kilobytes in size.

22. The method of claim 16, wherein the condition checking step checks for the following preventive condition:

a file which is larger than four gigabytes in size.

23. The method of claim 16, wherein the condition checking step checks for the following preventive condition:

a bad cluster at a location that would be used by a file system structure of the simpler file system.

24. A computer storage medium having a configuration that represents data and instructions which will cause performance of the method steps in claim 16.

25. A system comprising:

at least one computer having a processor in operable connection with a memory;

a partitionable storage medium having at least one partition, the partition identified by file system identification information and containing an advanced file system, the advanced file system accessible for manipulation by use of the processor;

wherein the system is configured to perform a method to at least attempt conversion of an advanced file system to a simpler file system, the method including the steps of;

checking for at least one preventive condition in the advanced file system that prevents completion of a file system conversion from the advanced file system to the simpler file system;

discontinuing an attempted file system conversion without completing it if such a preventive condition is found; and

completing the file system conversion if no such preventive condition is found.

26. The system of claim 25, configured so the creating step at least partially overwrites a file system structure of the advanced file system with a file system structure of the simpler file system.

27. The system of claim 25, configured so the method further comprises vacating space, and the creating step creates file system structures of the simpler file system at least partially in such vacated space.

28. The system of claim 25, wherein the advanced file system includes at least one NTFS index, and the method comprises deleting that index such that no corresponding index appears in a FAT file system produced by the method.

29. The system of claim 25, wherein the advanced file system includes at least one NTFS named data stream, and the method comprises at least one of:

deleting a named data stream such that no corresponding data appears in a FAT file system on the system, and saving the data of a named data stream so it appears in a file in a FAT file system on the system.

30. The system of claim 25, wherein the advanced file system includes at least one NTFS file having two or more versions, and the method comprises at least one of:

deleting at least one version'"'"'s data such that no corresponding data appears in a FAT file system on the system, and saving the data from each of at least two of the versions so that each version'"'"'s data appears in a FAT file system on the system.

31. The system of claim 25, wherein the file system identification information identifies an NTFS advanced file system.

32. The system of claim 25, wherein the file system identification information identifies an ext2fs advanced file system.

33. The system of claim 25, wherein the advanced file system includes at least one access control list restricting access to a file, and the method comprises deleting that access control list such that no corresponding access restrictions appear in a FAT file system produced by the method.

34. The system of claim 25, wherein the advanced file system includes at least one NTFS user storage quota for a file, and the method comprises deleting that storage quota such that no corresponding storage restriction appears in a FAT file system produced by the method.

35. The system of claim 25, wherein the condition checking step checks for at least one of the following preventive conditions:

a lack of sufficient space to hold file system structures of the simpler file system;

files compressed by a file system driver;

sparse files;

a file with more than one short name and one long name, both in the same directory;

clusters which are at least sixty-four kilobytes in size;

a file which is larger than four gigabytes in size;

a bad cluster at a location that would be used by a file system structure of the simpler file system.

36. The system of claim 25, wherein the condition checking step checks for at least two of the following preventive conditions:

a lack of sufficient space to hold file system structures of the simpler file system;

files compressed by a file system driver;

sparse files;

a file with more than one short name and one long name, both in the same directory;

clusters which are at least sixty-four kilobytes in size;

a file which is larger than four gigabytes in size;

a bad cluster at a location that would be used by a file system structure of the simpler file system.

37. The system of claim 25, wherein the condition checking step checks for at least three of the following preventive conditions:

a lack of sufficient space to hold file system structures of the simpler file system;

files compressed by a file system driver;

sparse files;

a file with more than one short name and one long name, both in the same directory;

clusters which are at least sixty-four kilobytes in size;

a file which is larger than four gigabytes in size;

a bad cluster at a location that would be used by a file system structure of the simpler file system.

38. The system of claim 25, wherein the system comprises:

at least two computers, each having at least a memory, a processor, and I/O devices, the computers being connected for communication between the computers;

a means for deleting at least one predetermined advanced file system feature from a selected partition on one of the computers without user feedback; and

a means for deleting at least one other predetermined advanced file system feature from the selected partition after user feedback agreeing to the deletion.