This paper describes how the Revision Control System (RCS) handles the problems of configuration management, history management, and version control. RCS is a set of UNIX commands which can be used with a modified version of the MAKE program.

The paper first provides a very clear description of the basic RCS commands, how a RCS revision tree is organized, and how RCS uses reverse deltas to ensure fast access to the latest revision of a program. The configuration management features of RCS, which make it a more powerful tool than its UNIX predecessor SCCS, are also described. Two appendixes include a useful survey of version control tools and a more detailed synopsis of the RCS commands.

The one downfall in this otherwise excellent paper is the section on usage statistics. The statistics presented support the theory that the space required for deltas is small. Unfortunately, since no estimate is given for the additional CPU time required to store and retrieve programs, the reader cannot judge the space-time tradeoff implicit in using RCS. Also, the statistics presented are from an academic research environment and do not represent the performance to be expected if RCS were used for commercial software development or maintenance.