Pysync has both a demonstration implementation of the rsync and related algorithms in pure Python, and a high speed librsync Python extension. The pure Python is not fast and is not optimized, however it does work and provides a simple implementation of the algorithm for reference and experimentation. It includes a combination of ideas taken from librsync, xdelta, and rsync. The librsync Python extension is less flexible and harder to understand, but is very fast.
Jeremi is groupware software for realtime document sharing. It supports distributed work on different documents or files by different people or project groups. It offers an always-up-to-date view of the project and its files and coordinates the dependency of the actual file status and access to those files. Jeremi is written entirely in Java.
Samba TNG is a tiny SMB/CIFS suite (server, client, and utilities) for Unix-like operating systems. This software is concentrating on MSRPC interoperability with Windows NT, 2000, XP, Vista, 2003, and 2008. Windows 7 support is in progress. It provides PDC support and tools to remotely administer NT servers and workstations.