rzip is a compression program, similar in functionality to gzip or bzip2, but able to take advantage long distance redundencies in files, which can sometimes allow rzip to produce much better compression ratios than other programs. The original idea behind rzip is described in my PhD thesis (see http://samba.org/~tridge/), but the implementation in this version is considerably improved from the original implementation. The new version is much faster and also produces a better compression ratio.

http://rzip.samba.org/