Determining when a low fidelity property value has changed during a sync

• US 6,950,835 B1
• Filed: 06/28/2004
• Issued: 09/27/2005
• Est. Priority Date: 04/30/2004
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Starbuck, Bryan T.
• Primary Examiner(s): Alam, Shahid
• Assistant Examiner(s): FLEURANTIN, JEAN B
• Application Number:
  US10/878,717
• Time in Patent Office: 456 Days
• Field of Search: 707 1- 10, 707100-1041, 707200-206, 709/248, 709/218
• US Class Current: 1/1
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor
• CPC Class Codes: G06F 16/275 Synchronous replication
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: Y10S 707/966 Distributed
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99954 Version management

Abstract

During synchronization of data between a remote device and a local device, it can be determined if a value for a property on a remote device has changed since a last synchronization of the property between the remote device and a local machine. A remote representation of a property value is compared to a local representation associated with the same property value. If the representations are identical, it can be determined that the property value did not change on the remote device. If, however, they are not identical then the property value must have changed after the remote representation was generated.

Claims

1. In a distributed computing system capable of synchronizing data between devices, a method of determining if a value for a property on a remote device has changed since a last synchronization of the property between the remote device and a local machine, the method comprising the acts of:

receiving a current value for a remote property and a remote representation for a prior value of the remote property;

receiving a remote representation of time date information associated with the remote property, wherein the remote representation of the time-date information is one or more of a Hexadecimal number, stored down to the seconds, stored down to the minutes or stored in a time zone independent format;

generating a local representation of the remote property from the current value for the remote property;

comparing the remote representation to the local representation;

determining, based on the comparison, that the prior value of the remote property was changed after the remote representation was generated; and

based on the determination that the prior value of the remote property was changed, determining that the remote representation of time-date information is potentially unreliable.

2. The method of claim 1, wherein the remote representation is a hash of the prior value of the remote property and the local representation is a hash of the current value for the remote property.

3. The method of claim 2, wherein the remote device is a low fidelity device that stores properties in a data base without a corresponding time-date field.

4. The method of claim 1, wherein a conflict exists between the current value and a local value associated with the remote property, and wherein the remote representation of time-date information is not used for resolving the conflict.

5. The method of claim 1, wherein a local value is used to replace the current value and the remote representation is replaced with an updated remote representation.

6. The method of claim 5, wherein the remote representation is a hash of the prior value of the remote property, the local representation is a hash of the current value for the remote property, and the updated remote representation is a hash of the local value.

7. In a distributed computing system capable of synchronizing data between devices, a method of determining if a value for a property on a remote device has changed since a last synchronization of the property between the remote device and a local machine, the method comprising the acts of:

receiving a remote value for a remote property and a remote representation for the remote value of the remote property;

receiving a remote representation of time date information associated with the remote property, wherein the remote representation of the time-date information is one or more of a Hexadecimal number, stored down to the seconds, stored down to the minutes or stored in a time zone independent format;

generating a local representation of the remote property from the remote value for the remote property;

comparing the remote representation to the local representation;

determining, based on the comparison, that the remote value of the remote property has not changed after the remote representation was generated;

determining that a conflict exists between the remote value and a local value associated with the remote property;

based on the determination that the remote value of the remote property has not changed, comparing the remote representation of time date information with a local representation of time date information, the remote representation of time date information and the local representation of time date information indicating when the remote value and local value were generated, respectively; and

resolving the conflict based on the results of the comparison of the remote representation of time date to the local representation of time date information.

8. The method of claim 7, wherein the remote representation is a hash of the remote value and the local representation is a hash of the remote value.

9. The method of claim 8, wherein the remote device is a low fidelity device that stores properties in a data base without a corresponding time-date field.

10. The method of claim 7, wherein the local value is used to replace the remote value and the remote representation is replaced with an updated remote representation.

11. The method of claim 10, wherein the remote representation is a hash of the prior value of the remote property, the local representation is a hash of the current value for the remote property, and the updated remote representation is a hash of the local value.

12. In a distributed computing system capable of synchronizing data between devices, a computer program product for implementing a method of determining if a value for a property on a remote device has changed since a last synchronization of the property between the remote device and a local machine, the computer program product comprising one or more computer readable media having stored thereon computer executable instructions that, when executed by a processor, can cause the distributed computing system to perform the following:

receive a current value for a remote property and a remote representation for a prior value of the remote property;

receive a remote representation of time date information associated with the remote property, wherein the remote representation of the time-date information is one or more of a Hexadecimal number, stored down to the seconds, stored down to the minutes or stored in a time zone independent format;

generate a local representation of the remote property from the current value for the remote property;

compare the remote representation to the local representation;

determine, based on the comparison, that the prior value of the remote property was changed after the remote representation was generated; and

based on the determination that the prior value of the remote property was changed, determine that the remote representation of time-date information is potentially unreliable.

13. The computer program product of claim 12, wherein the remote representation is a hash of the prior value of the remote property and the local representation is a hash of the current value for the remote property.

14. The computer program product of claim 13, wherein the remote device is a low fidelity device that stores properties in a data base without a corresponding time-date field.

15. The computer program product of claim 12, wherein a conflict exists between the current value and a local value associated with the remote property, and wherein the remote representation of time-date information is not used for resolving the conflict.

16. The computer program product of claim 12, wherein a local value is used to replace the current value and the remote representation is replaced with an updated remote representation.

17. The computer program product of claim 16, wherein the remote representation is a hash of the prior value of the remote property, the local representation is a hash of the current value for the remote property, and the updated remote representation is a hash of the local value.

18. In a distributed computing system capable of synchronizing data between devices, a computer program product for implementing a method of determining if a value for a property on a remote device has changed since a last synchronization of the property between the remote device and a local machine, the computer program product comprising one or more computer readable media having stored thereon computer executable instructions that, when executed by a processor, can cause the distributed computing system to perform the following:

receive a remote value for a remote property and a remote representation for the remote value of the remote property;

receive a remote representation of time date information associated with the remote property, wherein the remote representation of the time-date information is one or more of a Hexadecimal number, stored down to the seconds, stored down to the minutes or stored in a time zone independent format;

generate a local representation of the remote property from the remote value for the remote property;

compare the remote representation to the local representation;

determine, based on the comparison, that the remote value of the remote property has not changed after the remote representation was generated;

determine that a conflict exists between the remote value and a local value associated with the remote property;

based on the determination that the remote value of the remote property has not changed, compare the remote representation of time date information with a local representation of time date information, the remote representation of time date information and the local representation of time date information indicating when the remote value and local value were generated, respectively; and

resolve the conflict based on the results of the comparison of the remote representation of time date to the local representation of time date information.

19. The computer program product of claim 18, wherein the remote representation is a hash of the remote value and the local representation is a hash of the remote value.

20. The computer program product of claim 19, wherein the remote device is a low fidelity device that stores properties in a data base without a corresponding time-date field.

21. The computer program product of claim 18, wherein the local value is used to replace the remote value and the remote representation is replaced with an updated remote representation.

22. The computer program product of claim 21, wherein the remote representation is a hash of the prior value of the remote property, the local representation is a hash of the current value for the remote property, and the updated remote representation is a hash of the local value.