Method and system for synchronizing data shared among peer computing devices

• US 20040172423A1
• Filed: 02/28/2003
• Published: 09/02/2004
• Est. Priority Date: 02/28/2003
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Guzak, Chris J., Raman, Balan Sethu, Chitre, Sudarshan A., Flo, Eric R., Kaasten, Shaun A., Moore, Jason F., Saathoff, Jeffrey M., Orbits, David A.
• Granted Patent: US 7,743,022 B2
• Time in Patent Office: Days
• US Class Current: 707/201
• CPC Class Codes: G06F 16/1787 Details of non-transparently synchronising file systems

Abstract

Disclosed is a data synchronization service for use in a peer-to-peer computing environment. Selected data objects are copied onto selected computing devices. A service running on each device monitors data objects for changes. When a change is detected, the service sends a change notification to the other devices so that they can update their copies of the data object. A user can access a data object from any device, knowing that he will retrieve the latest version of the data object. Instead of incurring the costs of storing a large file on every device, a user “ghosts” the file on some devices. A ghosting device stores only metadata about the file rather than the entire file. The user accesses the file through the ghost: access requests are sent to a device that holds the actual contents, and those contents are presented to the user as if they were stored locally.

Claims

1. A method on a first computing device for synchronizing changes to a first data object on the first computing device with changes to a second data object on a second computing device, the method comprising:

configuring synchronization between the first and second data objects;

monitoring the first data object for changes;

if the first data object changes, then transmitting to the second computing device a notification of the change to the first data object;

listening for notifications of changes to the second data object; and

if a notification of a change to the second data object is received, and if the received change is appropriate to the first data object, then applying to the first data object the received change.

2. The method of claim 1 wherein configuring synchronization comprises checking the second computing device for authorization to synchronize with the first computing device.

3. The method of claim 1 wherein configuring synchronization comprises setting up encryption parameters for communications between the first and second computing devices.

4. The method of claim 1 wherein configuring synchronization between the first and second data objects comprises bringing the first and second data objects into the same state.

5. The method of claim 4 wherein bringing the first and second data objects into the same state comprises:

if the data of the first data object are newer than the data of the second data object, or if the second data object does not exist, then transmitting a copy of the first data object to the second computing device;

else if the data of the second data object are newer than the data of the first data object, or if the first data object does not exist, then receiving from the second computing device a copy of the second data object and updating the first data object from the received copy of the second data object.

6. The method of claim 4 wherein the first data object is a first folder;

wherein the second data object is a second folder; and

wherein bringing the first and second data objects into the same state comprises;

for each third data object contained within the first folder, bringing the third data object into the same state as a corresponding fourth data object within the second folder; and

receiving from the second computing device copies of data objects and, for each received copy for which there is no corresponding data object within the first folder, creating a new data object within the first data folder from the received copy.

7. The method of claim 1 wherein monitoring the first data object for changes comprises intercepting calls to a file system on the first computing device.

8. The method of claim 1 wherein monitoring the first data object for changes comprises monitoring a first file for changes selected from the group consisting of:

an attribute of the first file is modified, data in the first file are modified, the first file is moved, and the first file is deleted.

9. The method of claim 1 wherein monitoring the first data object for changes comprises monitoring a first folder for changes selected from the group consisting of:

an attribute of the first folder is modified, a third data object is created within the first folder, the first folder is moved, and the first folder is deleted.

10. The method of claim 9 further comprising:

monitoring a third data object within the first folder for changes.

11. The method of claim 10 wherein monitoring a third data object for changes comprises monitoring the third data object for changes selected from the group consisting of:

an attribute of the third data object is modified, data in the third data object are modified, a fourth data object is created within the third data object, the third data object is moved, and the third data object is deleted.

12. The method of claim 10 further comprising:

if the third data object changes, then transmitting to the second computing device a notification of the change to the third data object.

13. The method of claim 10 further comprising:

if the third data object changes, then checking whether changes to the third data object are to be synchronized with changes on the second computing device, and if changes to the third data object are to be synchronized, then transmitting to the second computing device a notification of the change to the third data object.

14. The method of claim 1 wherein monitoring the first data object comprises monitoring a first ghost;

and

wherein the received change is appropriate to the first ghost if the received change is selected from the group consisting of;

an attribute of the second data object is modified, the second data object is moved, and the second data object is deleted.

15. The method of claim 1 wherein monitoring the first data object comprises comparing a modification time of the first data object with a modification time of the second data object.

16. The method of claim 1 wherein transmitting to the second computing device comprises transmitting over a communications medium selected from the group consisting of:

a serial communications line, a parallel communications line, a local area network, an intranet, a modem link, and the Internet.

17. The method of claim 1 wherein transmitting a notification of the change comprises transmitting an XML-formatted notification.

18. The method of claim 1 further comprising:

if a notification of a change to the first data object is transmitted, then checking for status information from the second computing device about applying to the second data object the transmitted change; and

if a notification of a change to the second data object is received, then providing to the second computing device status information about applying to the first data object the received change.

19. The method of claim 1 further comprising:

intercepting a proposed change to the first data object; and

if the proposed change may have an unexpected effect on the second computing device, then warning a user of the first computing device of the possible unexpected effect.

20. The method of claim 19 wherein the first data object is a first folder;

wherein the second data object is a second folder;

wherein the proposed change comprises moving a third data object from within the first folder to a first location outside the first folder; and

wherein warning a user comprises warning that the proposed change would delete a fourth data object in the second folder, the fourth data object corresponding to the third data object, without creating a new data object on the second computing device in a second location corresponding to the first location on the first computing device.

21. The method of claim 19 wherein the first data object is a first folder;

wherein the second data object is a second folder;

wherein the proposed change comprises moving a third data object from a first location outside the first folder to within the first folder; and

wherein warning a user comprises warning that the proposed change would create a new data object within the second folder, the new data object corresponding to the third data object, without deleting a fourth data object on the second computing device in a second location corresponding to the first location on the first computing device.

22. The method of claim 1 further comprising:

collecting notifications of changes to the first data object; and

transmitting to the second computing device the collected notifications on a basis selected from the group consisting of;

a schedule, availability of the first computing device to transmit notifications, and availability of the second computing device to receive notifications.

23. The method of claim 1 further comprising:

upon receiving a command to pause synchronization with the second computing device, collecting notifications of changes to the first data object and not transmitting the notifications to the second computing device until a command to resume synchronization is received.

24. The method of claim 1 further comprising:

configuring synchronization between the first data object and a third data object on a third computing device;

if the first data object changes, then transmitting to the third computing device a notification of the change to the first data object;

listening for notifications of changes to the third data object; and

if a notification of a change to the third data object is received, then applying to the first data object the received change.

25. A computer-readable medium containing instructions for performing a method on a first computing device for synchronizing changes to a first data object on the first computing device with changes to a second data object on a second computing device, the method comprising:

configuring synchronization between the first and second data objects;

monitoring the first data object for changes;

if the first data object changes, then transmitting to the second computing device a notification of the change to the first data object;

listening for notifications of changes to the second data object; and

if a notification of a change to the second data object is received, and if the received change is appropriate to the first data object, then applying to the first data object the received change.

26. A method on a first computing device for synchronizing changes to a first data object on the first computing device with changes to a second data object on a second computing device, the method comprising:

configuring synchronization between the first and second data objects;

monitoring the first data object for changes;

if the first data object changes, and if the change is appropriate to the second data object, then transmitting to the second computing device a notification of the change to the first data object;

listening for notifications of changes to the second data object; and

if a notification of a change to the second data object is received, and if the received change is appropriate to the first data object, then applying to the first data object the received change.

27. The method of claim 26 wherein the second data object is a ghost;

and

wherein the change to the first data object is appropriate to the ghost if the change is selected from the group consisting of;

an attribute of the first data object is modified, the first data object is moved, and the first data object is deleted.

28. A computer-readable medium containing instructions for performing a method on a first computing device for synchronizing changes to a first data object on the first computing device with changes to a second data object on a second computing device, the method comprising:

configuring synchronization between the first and second data objects;

monitoring the first data object for changes;

if the first data object changes, and if the change is appropriate to the second data object, then transmitting to the second computing device a notification of the change to the first data object;

listening for notifications of changes to the second data object; and

if a notification of a change to the second data object is received, and if the received change is appropriate to the first data object, then applying to the first data object the received change.

29. A system for configuring data object synchronization, the system comprising:

an interface that presents to a user of a first computing device options selected from the group consisting of;

select a data object for synchronization, deselect a data object, select a second computing device for synchronization, deselect a second computing device, set a schedule for synchronization with a second computing device, pause synchronization with a second computing device, resume synchronization with a second computing device, and report synchronization status of a data object;

a data object synchronizer for implementing the user'"'"'s data object synchronization selections; and

a communications facility for communicating synchronization information with a selected second computing device.