an underlying theory of patches, which allows for safe reordering and

merging of patches even in complex scenarios. For all its power, Darcs

remains a very easy to use tool for every day use because it follows the

principle of keeping simple things simple.  Darcs is free software

licensed under the GNU GPL.</p>

<h2><a href="http://evergreen-ils.org/">Evergreen</a></h2>

<p>The Evergreen Project develops an open source ILS (integrated library

system) used by hundreds of libraries across the world. The software, also

called Evergreen, is used by libraries to provide their public catalog

interface as well as to manage back-of-house operations such as