ClearCase is a distributed client-server version control system. ClearCase is a variant DSEE tools, formerly available on Apollo platforms. Conceptually, mvfs adds another dimension to a regular Unix filesystem. The new axis is used to store the different versions of files and to provide a tree-hierarchical view of a collection of objects that might be scattered across any number of separate hosts on your local network. This technique conserves disk space because it doesn't keep private copies of read-only files.
Directories are version-controlled objects as well as files.
A graphical merge tool is provided. Like RCS, ClearCase supports branches, symbolic tags, and delta compression. A make-compatible build facility is provided that can identify common object code and share it among developers. A build auditing feature automatically records file dependencies by tracking every file that is opened when producing a derived object, thus making explicit dependency lists unnecessary. User-defined attributes can be assigned to any version or object.