RCS manages software libraries. It greatly increases programmer productivity by providing the following functions. 1. RCS stores and retrieves multiple revisions of program and other text. 2. RCS maintains a complete history of changes. 3. RCS manages multiple lines of development. 4. RCS can merge multiple lines of development. 5. RCS flags coding conflicts. 6. RCS resolves access conflicts. 7. RCS provides high-level retrieval functions. 8. RCS provides release and configuration control. 9. RCS performs automatic identification of modules with name, revision number, creation time, author, etc. 10. Provides high-level management visibility. 11. RCS is fully compatible with existing software development tools. 12. RCS' basic user interface is extremely simple. 13. RCS simplifies software distribution if customers main- tain sources with RCS also. 14. RCS needs little extra space for the revisions (only the differences). 15. RCS is implemented with reverse deltas. This means that the latest revision, which is the one that is accessed most often, is stored intact. This results in fast access time for the revision needed most often.