FSFS
Apache Subversion (often abbreviated SVN, after the command name svn) is a software versioning and revision control system distributed under an open source license. Developers use Subversion to maintain current and historical versions of files such as source code, web pages, and documentation. Its goal is to be a mostly compatible successor to the widely used Concurrent Versions System (CVS).
The open source community has used Subversion widely: for example in projects such as Apache Software Foundation, Free Pascal, FreeBSD, GCC, Mono and SourceForge. Google Code also provides Subversion hosting for their open source projects. BountySource systems use it exclusively. CodePlex offers access to Subversion as well as to other types of clients.
The corporate world has also started to adopt Subversion. A 2007 report by Forrester Research recognized Subversion as the sole leader in the Standalone Software Configuration Management (SCM) category and as a strong performer in the Software Configuration and Change Management (SCCM) category.
Subversion was created by CollabNet Inc. in 2000 and is now a top-level Apache project being built and used by a global community of contributors.
Read more about FSFS: History, Features, Layers, Filesystem, Properties, Branching and Tagging, Limitations and Problems, Development and Implementation