Yesterday I came across a study done by Diomidis Spinellis about the development of FreeBSD. It was written in 2006 but it still gives some useful insight in and statistics about the FreeBSD Project (How the FreeBSD Project works).
FreeBSD is a sophisticated operating system developed and maintained as open-source software by a team of more than 350 individuals located throughout the world. This study uses developer location data, the configuration management repository, and records from the issue database to examine the extent of global development and its effect on productivity, quality, and developer cooperation. The key findings are that global development allows round-the-clock work, but there are some marked differences between the type of work performed at different regions. The effects of multiple dispersed developers on the quality of code and productivity are negligible. Mentoring appears to be sometimes associated with developers living closer together, but ad-hoc cooperation seems to work fine across continents.
FreeBSD is a sophisticated operating system available for a number of modern architectures. It is a complete operating system (rather than just a kernel, like Linux) derived from BSD Unix, the version of Unix developed at the University of California, Berkeley. FreeBSD, known for its stability and reliability, runs the servers of large portals like Yahoo and hosting providers like the Host Department; parts of it also form the basis for Apple’s Mac OS X. Given the global nature of the FreeBSD development model, the objective of this work is to examine its extent, determine its effects on quality and productivity, and explore how geographic distance affects cooperation among the project’s members.