Aegis is a transaction-based software configuration management system. It
provides a framework within which a team of developers may work on many
changes to a program independently, and Aegis coordinates integrating these
changes back into the master source of the program, with as little disruption
as possible. Some key features:

* All operations on the repository are based on change sets.
* True configurations. All changes are reproducible snapshots. Every change
  set has a unique configuration identifier.
* Ability to rename files without losing their history.
* Binary files are supported.
* File meta-data are versioned. Aegis versions permissions also.
* Commits are truly atomic. No part of a commit takes effect until the entire
  commit has succeeded. Log messages are attached to the change set, not
  stored redundantly in each file.
* Access controls on lines of development (branches). Creating a branch in
  Aegis can be accomplished with a single, fast command.
* Repository synchronization, geographically distributed development.
* Optimal performance for all users, local or remote (no difference).
* Disconnected commits.
* Peer-to-peer architecture. Work may flow in without involving a master site.
* Costs are proportional to change size, not data size.

WWW: http://aegis.sourceforge.net/