Automated hoarding for mobile computers

A common problem facing mobile computing is disconnected operation, or computing in the absence of a network. Hoarding eases disconnected operation by selecting a subset of the user’s files for local storage. We describe a hoarding system that can operate without user intervention, by observing user activity and predicting future needs. The system calculates a new measure, semantic distance, between individual files, and uses this to feed a clustering algorithm that chooses which files should be hoarded. A separate replication system manages the actual transport of data; any of a number of replication systems may be used. We discuss practical problems encountered in the real world and present usage statistics showing that our system outperforms previous approaches by factors that can exceed 10:1.

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