Method and apparatus for protecting user data during power failures in a data processing system

• US 6,535,996 B1
• Filed: 10/07/1999
• Issued: 03/18/2003
• Est. Priority Date: 10/07/1999
• Status: Expired due to Fees

• Current Assignee: Lenovo Singapore Pte Limited (Lenovo Group Ltd.)
• Original Assignee: International Business Machines Corporation
• Inventors: Gupta, Sanjay, Brewer, James Arthur
• Primary Examiner(s): Baderman, Scott
• Assistant Examiner(s): LOHN, JOSHUA A
• Application Number:
  US09/414,332
• Time in Patent Office: 1,258 Days
• Field of Search: 714/14, 714/22, 714/24
• US Class Current: 714/14
• CPC Class Codes: G06F 11/1441 Resetting or repowering
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery

Abstract

A method and system for protecting user data during power failures on a network-computer-class data processing system is provided. The network-computer-class data processing system is integrated with a power supply having an early power fail warning signal to ensure that unsaved changes to user data files are saved before a complete power failure strikes the data processing system. As a user employs one or more applications to create or modify data files, a table of file changes is created for each user data file that is opened by the user. This table is kept in non-volatile media, preferably on the user'"'"'s network computer but possibly on a server located on a network connected to the network computer if the network computer lacks non-volatile memory. The entire contents of the table are saved to non-volatile storage in the time interval between the early power fail warning signal going active and the power completely failing. The table of user data changes can then be applied to recreate the user'"'"'s data after power is restored.

Claims

1. A method of preserving data integrity during periods of unstable power supply in a data processing system, the method comprising the computer-implemented steps of:

tracking changes made by a user to data files;

receiving an early power fail warning signal, wherein the early power fail warning signal provides an indication that a power supply in the data processing system has become unstable;

in response to the early power fail warning signal, storing the tracked changes in non-volatile memory;

creating a change record file for a data file modified by a user; and

generating a change record in the change record file for each change to the data file.

2. The method of claim 1 wherein the non-volatile memory is flash or hardfile memory in the data processing system.

3. The method of claim 1 wherein the non-volatile memory is permanent storage in a server on a network connected to the data processing system.

4. The method of claim 1 further comprising:

providing the early power fail warning signal in response to a determination that the power supply has dropped below a configurable level.

5. The method of claim 1 wherein the step of storing the tracked changes in non-volatile memory is completed within a predetermined period of time.

6. The method of claim 1 wherein a plurality of change record files are created for each data file modified by a user.

7. The method of claim 1 further comprising:

storing the change record file in non-volatile memory in response to a number of change records in the change record file equaling a predetermined value.

8. The method of claim 1 further comprising:

storing the change record file in non-volatile memory at predetermined time intervals.

9. The method of claim 1, wherein the tracked changes are stored using power from the power supply.

10. An apparatus for preserving data integrity during periods of unstable power supply in a data processing system, the apparatus comprising:

tracking means for tracking changes made by a user to data files;

receiving means for receiving an early power fail warning signal, wherein the early power fail warning signal provides an indication that a power supply in the data processing system has become unstable;

first storming means for storing, in response to the early power fail warning signal, the tracked changes in non-volatile memory;

creating means for creating a change record file for a data file modified by a user; and

generating means for generating a change record in the change record file for each change to the data file.

11. The apparatus of claim 10 wherein the non-volatile memory is flash or hardfile memory in the data processing system.

12. The apparatus of claim 10 wherein the non-volatile memory is permanent storage in a server on a network connected to the data processing system.

13. The apparatus of claim 10 further comprising:

providing means for providing the early power fail warning signal in response to a determination that the power supply has dropped below a configurable level.

14. The apparatus of claim 10 wherein the first storing means operates within a predetermined period of time.

15. The apparatus of claim 10 wherein a plurality of change record files arc created for each data file modified by a user.

16. The apparatus of claim 10 further comprising:

second storing means for storing the change record file in non-volatile memory in response to a number or change records in the change record file equaling a predetermined value.

17. The apparatus of claim 10 further comprising:

third storing means for storing the change record file in non-volatile memory at predetermined time intervals.

18. A computer program product in a computer-readable medium for use in a data processing system for preserving data integrity during periods of unstable power supply in the data processing system, the computer program product comprising:

first instructions for tracking changes made by a user to data files;

second instructions for receiving an early power fail warning signal, wherein the early power fail warning signal provides an indication that a power supply in the data processing system has become unstable;

third instructions for storing, in response to the early power fail warning signal, the tracked changes in non-volatile memory;

instructions for creating a change record file for a data file modified by a user; and

instructions for generating a change record in the change record file for each change to the data file.

19. The computer program product of claim 18 further comprising:

instructions for providing the early power fail warning signal in response to a determination that the power supply has dropped below a configurable level.

20. The computer program product of claim 18 further comprising:

instructions for storing the change record file in non-volatile memory in response to a number of change records in the change record file equaling a predetermined value.

21. The computer program product of claim 18 further comprising:

instructions for storing the change record file in non-volatile memory at predetermined time intervals.