CSRG has always been a small group of software developers. This resource limitation requires careful software-engineering management. Careful coordination is needed not only of CSRG personnel, but also of members of the general community who contribute to the development of the system.

Releases from Berkeley tend to alternate between those that introduce major new facilities and those that introduce bug fixes and efficiency improvements. This alternation allows timely releases, while providing for refinement and correction of the new facilities and the elimination of performance problems produced by the new facilities. The timely followup of releases that include new facilities reflects the importance CSRG places on providing a reliable and robust system on which its user community can depend.

The development of BSD illustrates an advantage of having a few principal developers: The developers all know the whole system thoroughly enough to be able to coordinate their own work with that of other people to produce a coherent final system. Companies with large development organizations find this result difficult to duplicate. This paper describes in more detail the process by which the development effort is managed.