Method and apparatus for data versioning and recovery using delta content save and restore management

• US 7,395,386 B2
• Filed: 01/18/2005
• Issued: 07/01/2008
• Est. Priority Date: 01/18/2005
• Status: Active Grant

• Current Assignee: Lenovo PC International Limited (Lenovo Group Ltd.)
• Original Assignee: Lenovo Singapore Pte Limited (Lenovo Group Ltd.)
• Inventors: Williamson, Paul Stuart, Brown, Michael Wayne, Barrs, John William
• Primary Examiner(s): Thai; Tuan V.
• Assistant Examiner(s): DARE, RYAN A
• Application Number:
  US11/037,157
• Publication Number:
  US 20060161598A1
• Time in Patent Office: 1,260 Days
• Field of Search: 711/161
• US Class Current: 711/161
• CPC Class Codes: G06F 16/219 Managing data history or versioning querying versioned data G06F16/2474; querying temporal data G06F16/2477

Abstract

A method, apparatus, and computer instructions for managing versioning data for memory segments. Responsive to a request from a requester to allocate a memory segment, the memory segment is allocated. A versioning data structure is created for the memory segment. The versioning data structure is used to store changes in data for the memory segment, and the memory segment includes a pointer to the versioning data structure. When a change in the data is detected for the memory segment, wherein the change in the data forms the delta data. Responsive to detecting the change in the data for the memory segment, the delta data is stored in the versioning data structure, wherein the versioning data structure is used to return the data in the memory segment to a prior state.

Claims

1. A method in a data processing system for managing versioning data for memory segments, the method comprising:

allocating a memory segment for data in response to a request from a requestor to allocate the memory segment;

creating within the memory segment a versioning data structure for the memory segment, wherein the versioning data structure is used to store delta data for changes in the data for the memory segment, and wherein the memory segment is associated with the versioning data structure;

detecting a change in the data for the memory segment;

responsive to detecting the change in the data for the memory segment, storing the delta data in the versioning data structure within the memory segment, wherein the delta data is the change in the data between a prior version and a current version of the data in a changed form; and

returning a reference to the memory segment containing the versioning data structure to the requestor that requested allocation of the memory segment.

2. The method of claim 1 further comprising;

returning the memory segment to the prior state using the versioning data structure.

3. The method of claim 1, wherein the memory segment is associated with the versioning data structure using at least one of a pointer and an offset.

4. The method of claim 1, wherein the allocating step, the creating step, the detecting step, and the storing step are located in a memory management subsystem.

5. The method of claim 1, wherein the memory management subsystem is located in a virtual machine.

6. The method of claim 5, wherein the virtual machine is a Java virtual machine.

7. The method of claim 1, wherein the allocating step comprises:

allocating the memory segment to include space for the versioning data structure.

8. The method of claim 1, wherein the versioning data structure is a linked list.

9. The method of claim 1, wherein a versioning data structure is created for each allocated memory segment.

10. The method of claim 3, wherein the pointer is an offset to the versioning data structure.

11. The method of claim 3, wherein the pointer is located in a memory segment header in the memory segment.

12. The method of claim 1, wherein the memory segment is allocated prior to creation of the versioning data structure.

13. A computer program product having a computer recordable type medium for managing versioning data for memory segments, the computer program product comprising:

first instructions for allocating a memory segment for data in response to a request from a requestor to allocate the memory segment;

second instructions for creating within the memory segment a versioning data structure for the memory segment, wherein the versioning data structure is used to store delta data for changes in the data for the memory segment and wherein the memory segment is associated with the versioning data structure;

third instructions for detecting a change in the data for the memory segment;

fourth instructions, responsive to detecting the change in the data for the memory segment, storing the delta data in the versioning data structure within the memory segment, wherein the delta data is the change in the data between a prior version and a current version of the data in a changed form; and

fifth instructions for returning a reference to the memory segment containing the versioning data structure to the requestor that requested allocation of the memory segment.

14. The computer program product of claim 13 further comprising;

sixth instructions for returning the memory segment to the prior state using the versioning data structure.

15. The computer program product of claim 13, wherein the memory segment is associated with the versioning data structure using at least one of a pointer and an offset.

16. The computer program product of claim 13, wherein the first instructions, the second instructions, the third instructions, the fourth instructions, and the fifth instructions are executed in a memory management subsystem.

17. The computer program product of claim 13, wherein the memory management subsystem is located in a virtual machine.

18. The computer program product of claim 17, wherein the virtual machine is a Java virtual machine.

19. The computer program product of claim 13, wherein the first instructions comprises:

sub instructions for allocating the memory segment to include space for the versioning data structure.

20. The computer program product of claim 13, wherein the versioning data structure is a linked list.

21. The computer program product of claim 13, wherein a versioning data structure is created for each allocated memory segment.

22. The computer program product of claim 15, wherein the pointer is an offset to the versioning data structure.

23. A data processing system for managing versioning data for memory segments, the data processing system comprising:

allocating means for allocating a memory segment for data in response to a request from a requestor to allocate the memory segment;

creating means for creating within the memory segment a versioning data structure for the memory segment, wherein the versioning data structure is used to store delta data for changes in the data for the memory segment and wherein the memory segment is associated with the versioning data structure;

detecting means for detecting a change in the data for the memory segment;

storing means, responsive to detecting the change in the data for the memory segment, for storing the delta data in the versioning data structure within the memory segment, wherein the delta data is the change in the data between a prior version and a current version of the data in a changed form; and

returning means for returning a reference to the memory segment containing the versioning data structure to the requestor that requested allocation of the memory segment.

24. The data processing system of claim 23 further comprising;

returning means for returning the memory segment to the prior state using the versioning data structure.

25. The data processing system of claim 23, wherein the memory segment is associated with the versioning data structure using at least one of a pointer and an offset.

26. The data processing system of claim 23, wherein the allocating means, the creating means, the detecting means, and the storing means are located in a memory management subsystem.

27. The data processing system of claim 23, wherein the memory management subsystem is located in a virtual machine.

28. The data processing system of claim 27, wherein the virtual machine is a Java virtual machine.

29. A data processing system for managing versioning data for memory segments, the data processing system comprising:

a bus system;

a communications unit connected to the bus system;

a memory connected to the bus system, wherein the memory includes a set of instructions; and

a processing unit connected to the bus system, wherein the processing unit executes the set of instructions, responsive to a request from a requestor to allocate a memory segment, to allocate the memory segment for data;

create within the memory segment a versioning data structure for the memory segment, in which the versioning data structure is used to store changes in the data for the memory segment and in which the memory segment includes a pointer to the versioning data structure;

detect a change in the data for the memory segment, in which the change in the data forms delta data;

responsive to detecting the change in the data for the memory segment, store the delta data in the versioning data structure within the memory segment, in which the delta data is the change in the data between a prior version and a current version of the data in a changed form; and

return a reference to the memory segment containing the versioning data structure to the requestor that requested allocation of the memory segment.