Virtual file system and method

• US 6,895,591 B1
• Filed: 10/18/1999
• Issued: 05/17/2005
• Est. Priority Date: 10/18/1999
• Status: Expired due to Term

• Current Assignee: Unisys Corporation
• Original Assignee: Unisys Corporation
• Inventors: Kogen, Clark C., Prestifilippo, James C., Clarke, Steven E., Russ, Craig F.
• Primary Examiner(s): BULLOCK JR, LEWIS ALEXANDER
• Application Number:
  US09/420,210
• Time in Patent Office: 2,038 Days
• Field of Search: 707 1- 10, 719/310, 719/319, 719/328, 719/331, 719/332, 710/1, 710/5
• US Class Current: 719/332
• CPC Class Codes: G06F 16/10 File systems; File servers
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]
• CPC Class Codes: H04L 67/10 in which an application is distributed across nodes in the network software deployment G06F8/60; multiprogramming arrangements G06F9/46
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]

Abstract

A file accessing scheme allows logical files to be processed outside of the native operating system and its logical I/O subsystem. When an application program wants to process a file outside of the native operating system, a file information block is built with a special type of file designated as “virtual.” A pointer is provided within the file information block to a handler. The handler is a library that is external to the native operating system. The library processes the file without using the native operating system. Upon completion of the processing, the handler returns the operation results to the file information block and control is transferred back to the application program.

Claims

1. In a data processing system having a native operating system including a logical I/O subsystem which interacts with one or more files of an application program, a method comprising:

the application program requesting by a predesignated operating system method to perform one or more operations on a file;

creating a data structure when the predesignated operating system method is indicated which allows logical I/O routines to communicate with a handler, wherein the handler comprises a library, and wherein the handler is external to a native operating system kernel but within the data processing system;

the handler performing the one or more operations on the file;

the data structure returning completed operation results from the handler to the application program, and returning control of file operations to the application program; and

building a file information block when the application program opens a specified file, the file information block including attributes of the specified file, wherein the data structure is part of the file information block, and wherein the completed operation results from the handler are returned to the file information block.

2. The method of claim 1 wherein the files include data and the library performs a data processing function on the data.

3. The method of claim 1 wherein the file requires data from a resource type and the library performs a data retrieval function to obtain the required data.

4. The method of claim 1 wherein the predesignated operating system method is indicated by invoking a predesignated attribute specification.

5. The method of claim 4 wherein the predesignated attribute specification is KIND=VIRTUAL.

6. The method of claim 1 wherein the operation results include file attribute information, file data, and the result of the operation, the result indicating success or failure of the operation or the number of bytes transferred.

7. The method of claim 1 wherein the handler accesses one or more resource types which are not supported by the native operating system.

8. The method of claim 1 wherein the logical I/O subsystem interacts with the application program files using native logical I/O requests, and the handler receives from the data structure and understands and executes the same native logical I/O requests as the native operating system, while remaining external to the native operating system kernel.

9. An article of manufacture for use in a data processing system having a native operating system including a logical I/O subsystem which interacts with one or more files of an application program, the article of manufacture comprising a computer-readable medium holding computer-executable instructions for performing a method comprising:

providing a predesignated operating system method by which an application program can request to perform one or more operations on a file;

creating a data structure when the predesignated operating system method is indicated which allows logical I/O routines to communicate with a handler, wherein the handler comprises a library, and wherein the handler is external to a native operating system kernel but within the data processing system; and

building a file information block when the application program opens a specified file, the file information block including attributes of the specified file, wherein the data structure is part of the file information block, and wherein the completed operation results from the handler are returned to the file information block.

10. The article of manufacture of claim 9 wherein the files include data and the library performs a data processing function on the data.

11. The article of manufacture of claim 9 wherein the file requires data from a resource type and the library performs a data retrieval function to obtain the required data.

12. The article of manufacture of claim 9 wherein the predesignated operating system method is indicated by invoking a predesignated attribute specification.

13. The article of manufacture of claim 12 wherein the predesignated attribute specification is KIND=VIRTUAL.

14. The article of manufacture of claim 9 wherein the operation results include file attribute information, file data, and the result of the operation, the result indicating success or failure of the operation or the number of bytes transferred.

15. The article of manufacture of claim 9 wherein the handler accesses one or more resource types which are not supported by the native operating system.

16. The article of manufacture of claim 9 wherein the logical I/O subsystem interacts with the application program files using native logical I/O requests, and the handler receives from the data structure and understands and executes the same native logical I/O requests as the native operating system, while remaining external to the native operating system kernel.

17. In a data processing system having a native operating system including a logical I/O subsystem which interacts with one or more files of an application program, a file processing system comprising:

the application program requesting by a predesignated operating system method to perform one or more operations on a file;

a handler, wherein the handler comprises a library, and which is external to a native operating system kernel but within the data processing system, wherein the data structure allows logical I/O routines to communicate with the handler, the handler performing the one or more operations on the file, the data structure returning completed operation results from the handler to the application program, and returning control of file operations to the application program; and

a file information block which is built when the application program opens a specified file, the file information block including attributes of the specified file, wherein the data structure is part of the file information block, wherein the completed operation results from the handler are returned to the file information block.

18. The system of claim 17 wherein the files include data and the library performs a data processing function on the data.

19. The system of claim 17 wherein the file requires data from a resource type and the library performs a data retrieval function to obtain the required data.

20. The system of claim 17 wherein the application program indicates that it wants to perform one or more operations on an application program file in an environment external to the native operating system kernel by invoking a predesignated attribute specification.

21. The system of claim 20 wherein the predesignated attribute specification is KIND=VIRTUAL.

22. The system of claim 17 wherein the operation results include file attribute information, file data, and the result of the operation, the result indicating success or failure of the operation or the number of bytes transferred.

23. The system of claim 17 wherein the handler accesses one or more resource types which are not supported by the native operating system.

24. The system of claim 17 wherein the logical I/O subsystem interacts with the application program files using native logical I/O requests, and the handler receives from the data structure and understands and executes the same native logical I/O requests as the native operating system, while remaining external to the native operating system kernel.