Who? What? Where? Examining Distributed Development in Two Large Open Source Projects

To date, a large body of knowledge has been built up around understanding open source software development. However, there is limited research on examining levels of geographic and organizational distribution within open source software projects, despite many studies examining these same aspects in commercial contexts. We set out to fill this gap in OSS knowledge by manually collecting data for two large, mature, successful projects in an effort to assess how distributed both geographically and organizationally. Both Firefox and Eclipse have been the subject of many studies and are ubiquitous in the areas of software development and internet usage respectively. Further, both receive substantial development contributions from many companies. As such, both are worthy of study in order to understand the development processes that they use, how distributed the projects are, and what, if any, relationship distribution has with quality. To this end, we identified the top contributors that made 95% of the changes over multiple major releases of Firefox and Eclipse and determined their geographic locations and organizational affiliations. We found that Firefox is very geographically distributed with over a third of its components receiving major contributions from developers on different continents, and that components that are highly distributed have no more defects than those that are not. In contrast, Eclipse is directed and developed largely by one company; with IBM making 96% of the total commits (49% coming from one lab in Ottawa, Canada). We further examined the distribution in each project’s constituent subsystems and report the relationship of pre- and post-release defects with geographic and organizational factors.