Delta Update is a source package update system that performs similarly to diff/patch for packages. It can reconstruct compressed tarballs so that there is a perfect binary match with the old package. By using Deltup you can dramatically reduce network bandwidth by downloading an update patch instead of the complete tarball. Some of the results are rather impressive. See this page to get a some stats on popular file downloads.

Binary Delta is an advanced file differencing algorithm that is both efficient and fast. Deltup spends far more time with the compression step than with file differencing. BDelta also includes a library so that it can be used in your own applications.

The Dynamic Deltup Server was started by Nicolai Lissner. You can use it to create and download patches. See the HOWTO page for more info.