Macro-level software evolution: a case study of a large software compilation

Software evolution studies have traditionally focused on individual products. In this study we scale up the idea of software evolution by considering software compilations composed of a large quantity of independently developed products, engineered to work together. With the success of libre (free, open source) software, these compilations have become common in the form of ‘software distributions’, which group hundreds or thousands of software applications and libraries into an integrated system. We have performed an exploratory case study on one of them, Debian GNU/Linux, finding some significant results. First, Debian has been doubling in size every 2 years, totalling about 300 million lines of code as of 2007. Second, the mean size of packages has remained stable over time. Third, the number of dependencies between packages has been growing quickly. Finally, while C is still by far the most commonly used programming language for applications, use of the C++, Java, and Python languages have all significantly increased. The study helps not only to understand the evolution of Debian, but also yields insights into the evolution of mature libre software systems in general.

Daniel M. GermanEmail:

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Jesus M. Gonzalez-Barahona   teaches and researches in Universidad Rey Juan Carlos, Mostoles (Spain). His research interests include libre software development, with a focus on quantitative and empirical studies, and distributed tools for collaboration in libre software projects. He works in the GSyC/LibreSoft research team, . Gregorio Robles   is Associate Professor at the Universidad Rey Juan Carlos, where he earned his PhD in 2006. His research interests lie in the empirical study of libre software, ranging from technical issues to those related to the human resources of the projects. Martin Michlmayr   has been involved in various free and open source software projects for well over 10 years. He acted as the leader of the Debian project for two years and currently serves on the board of the Open Source Initiative (OSI). Martin works for HP as an Open Source Community Expert and acts as the community manager of FOSSBazaar. Martin holds Master degrees in Philosophy, Psychology and Software Engineering, and earned a PhD from the University of Cambridge. Juan José Amor   has a M.Sc. in Computer Science from the Universidad Politécnica de Madrid and he is currently pursuing a Ph.D. at the Universidad Rey Juan Carlos, where he is also a project manager. His research interests are related to libre software engineering, mainly effort and schedule estimates in libre software projects. Since 1995 he has collaborated in several libre software organizations; he is also co-founder of LuCAS, the best known libre software documentation portal in Spanish, and Hispalinux, the biggest spanish Linux user group. He also collaborates with and Linux+. Daniel M. German   is associate professor of computer science at the University of Victoria, Canada. His main areas of interest are software evolution, open source software engineering and intellectual property.