sorting algorithm used in bzip2 is limited to 900 KiB of history. The history buffer in rzip can be up to 900 MiB long, several orders of magnitude larger than gzip or bzip2. Rzip is often much faster than bzip2, despite using the bzip2 library as a back end. This is because rzip feeds bzip2 with shrunken data, so that bzip2 has to do less work. Simple comparisons (although too small for it to be an authoritative benchmark) have been produced. Disadvantages rzip is not suited for every purpose. The two biggest disadvantages of rzip are that it cannot be pipelined (so it cannot read from standard input or write to standard output), and that it uses a high amount of memory: a typical compression run on a large file might use hundreds of megabytes of RAM. If there is a lot of RAM to spare and a very high compression ratio is required, rzip should be used, but if these conditions are not satisfied, alternate compression methods such as gzip and bzip2, which are less memory-intensive, should be used instead of rzip. There is at least one patch to enable pipelining. History rzip was originally written by Andrew Tridgell as part of his PhD research. Alternative implementations lrzip lrzip (Long Range ZIP) is an improved version of rzip. Its file format (.lrz) is incompatible with rzip's. It has the following improvements: Choice of LZMA, LZO, DEFLATE, Bzip2, and ZPAQ compression (as opposed to Bzip2 only) No dictionary limit, not even limited by available RAM Ability to test data for compressibility before compressing, preventing the computer from wasting time by trying to compress incompressible data Ability to be pipelined from standard input / standard output (with a loss in compression ratio) Ability to disable last-stage compression for use with another compressor Optional AES-128 encryption The lrzip distribution comes with a pair of programs to use it with tar, lrztar and lrzuntar. rzip64 rzip64 is an extension of rzip for very large files that can utilize multiple CPU cores in parallel. There are benchmark results. Most important, however, is the ability of rzip64 to be interrupted at any time. Thereby a running compression task (that may easily take several hours for large files) survives even a system maintenance reboot without losing already completed work and can be resumed later. The file format of rzip64 is identical to the original rzip. REP