Microsoft Technology Licensing, LLC

Kevin R Hughes

Lev Novik

Ashish B Shah

Edward Eric Thomas

Neil Leonard Padgett

Erik Jonas Kallstrom

Salome Jacob

Stanislav S Kuvshinov

The subject disclosure is directed towards technology by which data transmission sizes are reduced when uploading files over a network. By processing hash values corresponding to a plurality of data blocks of a file to potentially be uploaded to a server, the server identifies any already known data block or blocks of the file. The server performs a server-local copy operation that writes the known data block into a server-local copy of the file. If applicable, the server returns hash values corresponding to unknown data blocks to a client, by which the client responds by uploading copies of the unknown data blocks. Accordingly, the client and the server maintain the server-local copy of the file by transferring only unknown data blocks.

Efficient data transmission between computing devices

A data store in which changes are not tracked is synchronized with a data store in which changes are tracked utilizing a shadow store. The shadow store contains shadow data indicative of the most recent synchronization operation between the data stores. The shadow data comprises hash values of the data items in the limited or non-change-tracked data store. Changes to data items in the limited or non-change-tracked data store are operated on to provide respective hash values. The hash values are compared with the hash values in the shadow data. If the hash values differ, changes are appropriately applied to the data store, and the shadow data is appropriately updated. In an example embodiment, hash values are obtained from one-way hash functions, such MD5, SHA-1, SHA-256, or the like.

Synchronization of change-tracked data store with data store having limited or no change tracking

Growing community of inventors

Redmond, WA, United States of America

Kevin R Hughes