APPARATUS AND METHOD FOR INCREMENTAL UPDATING OF ARCHIVE FILES

According to aspects of the present invention, an original archive file having one or more entries is created, where each entry in the original archive file is itself a file, and where each entry in the archive file may comprise any file type, including an archive file. The original archive file is transmitted to a client computer. Subsequently, a target archive file is created, wherein one or more of the entries in the target archive file are typically expected to be identical to one or more entries in the original archive file. Given the original archive file and the target archive file, a difference archive file is created. The difference archive file comprises an index file describing the changes between the original archive file and the target archive file, and also comprises a set of entries corresponding to the entries in the target archive file that are not contained in the original archive file. The difference archive file is transmitted to the client computer, instead of requiring that the entire target archive file be transmitted. At the client computer, the difference archive file is applied to the original archive file to produce a synthesized archive file, wherein the synthesized archive file is functionally identical to the target archive file, and wherein each entry in the synthesized archive file is identical to a corresponding entry in the target archive file.