Abstract: A system and method for generating and updating a file system on a client computer. An original file system may be compared to an updated file system and the differences between the two file systems may be defined in specific data blocks. The differences may include new data blocks, modified data blocks, and data blocks that have been deleted. The new data blocks or modified data blocks may be sent to the client computer along with reference file updates to update the file system on the client computer. A virtual file system on the client computer may be created using the set of data blocks and the reference files to point to which data blocks contain the data for specific files. As the file system is updated, new data blocks and modified data blocks may replace deleted data blocks in the set of data blocks.

Abstract: An improved system and method for reducing the size of data difference representations. The input data stream may be split into one or more output data streams such that the output data streams may be recombined and used to regenerate the original input data stream. Each of the output data streams may be independently differenced against the equivalent data stream from the previous version of the data. Non-localized changes in the input data stream may be converted into localized changes in a subset of the output data streams. The subset of output data streams no longer containing non-localized changes produce efficient (i.e., small) difference representations. The difference representations of each of these streams may be packaged into a single stream for transmission over a computer network. The receiving computer may reconstruct the multiplicity of difference representations, and recreate the multiplicity of translated data streams representing the updated data.

Abstract: A method and system of the present invention generates a representation of a new version of an original file system with reference to the original file system and the new version of the file system. Use of data from previous versions of the file system reduces the amount of data to be stored in the delta directory map file, delta modification data block file, and delta look up table generated for the data portions unique to the newest version of an original file system. The inventive process produces delta data block records that identify the location of data portions that may be used to generate the newest version of the file system. The data portions may be located in a file in the original file system, a delta modification data block file in a previous version of the original file system or a delta modification data block file for the newest version of the original file system.