zdelta: An efficient delta compression tool

Abstract

In this report we describe a tool for delta compression, i.e., the efficient encoding of a given data set in relation to another one. Its possible applications include archiving multiple versions of data, distribution of software updates, delta compression of backup files, or compression at the file system level. The compressor, called zdelta, could be viewed as a modification of the zlib compression library [4] with some additional ideas inspired by the vdelta/vcdiff tool of Vo [5]. We also present experimental results comparing zdelta to other delta compression tools. Additional information about zdelta, including source code and updates, is available at http://cis.poly.edu/zdelta/. This project was supported by a grant from Intel Corporation. Torsten Suel was also supported by NSF CAREER Award NSF CCR-0093400.