&TCAR; is supported by Subversion, a version control system which allows you to keep old versions of files and directories (usually source code), keep a log of who, when, and why changes occurred, etc., like CVS, RCS or SCCS. When using Subversion there is one source repository and many working copies of that source repository. The working copies are independent one another, can be distributed all around the world and provide a local place for designers, documentors, translators and programmers to perform their work in a descentralized way. The source repository, on the other hand, provides a central place for all independent working copies to interchange data and provides the information required to permit extracting previous versions of files at any time. The first level of directories in the repository provides organization through a convenctional trunk, branches and tags layout. In this configuration the trunk directory is where main changes take place, the tags directory is where frozen copies of trunk changes are placed in for releasing, and the branches directory is an intermediate place between trunk and tags states where changes take place before being merged into trunk and finally released into tags. The second level of directories in the repository provides organization for each work line described in . All other subsequent levels of directories in the repository, from third level on, are created to organize specific concepts related to the work line they are in. A complete reference for each directory inside &TCAR; is available at .