Dirk Riehle

The Total Growth of Open Source

Software development is undergoing a major change away from a fully closed software process towards a process that incorporates open source software in products and services. Just how significant is that change? To answer this question we need to look at the overall growth of open source as well as its growth rate. In this paper, we quantitatively analyze the growth of more than 5000 active and popular open source software projects. We show that the total amount of source code as well as the total number of open source projects is growing at an exponential rate. Previous research showed linear and quadratic growth in lines of source code of individual open source projects. Our work shows that open source is expanding into new domains and applications at an exponential rate.

The Economic Motivation of Open Source Software: Stakeholder Perspectives

Open source software has enabled large system integrators to increase their profits through cost savings and reach more customers due to flexible pricing. This has upset existing ecosystems and shuffled structural relationships, resulting in the emergence of firms providing consulting services to open source projects. This new breed of service firm in turn lives or dies by its ability to recruit and retain appropriate talent. For such talent, in particular for software developers, life has become more difficult and exciting at once. Developers face new career prospects and paths, since their formal position in an open source project, in addition to their experience and capabilities, determines their value to an employer. Economically rational developers strive to become commiters to high-profile open source projects to further their careers, which in turn generates more recognition, independence, and job security

How and why Wikipedia works: an interview with Angela Beesley, Elisabeth Bauer, and Kizu Naoko

This article presents an interview with Angela Beesley, Elisabeth Bauer, and Kizu Naoko. All three are leading Wikipedia practitioners in the English, German, and Japanese Wikipedias and related projects. The interview focuses on how Wikipedia works and why these three practitioners believe it will keep working. The interview was conducted via email in preparation of WikiSym 2006, the 2006 International Symposium on Wikis, with the goal of furthering Wikipedia research [1]. Interviewer was Dirk Riehle, the chair of WikiSym 2006. An online version of the article provides simplified access to URLs [2].

The Economic Case for Open Source Foundations

By establishing a successful open source platform, software firms can compete more effectively across technology stacks and thereby increase their addressable market.

Paid vs. Volunteer Work in Open Source

Many open source projects have long become commercial. This paper shows just how much of open source software development is paid work and how much has remained volunteer work. Using a conservative approach, we find that about 50% of all open source software development has been paid work for many years now and that many small projects are fully paid for by companies. However, we also find that any non-trivial project balances the amount of paid developer with volunteer work, and we suggest that the ratio of volunteer to paid work can serve as an indicator for the health of open source projects and aid the management of the respective communities.

Continuous Integration in Open Source Software Development

Commercial software firms are increasingly using and contributing to open source software. Thus, they need to understand and work with open source software development processes. This paper investigates whether the practice of continuous integration of agile software development methods has had an impact on open source software projects. Using fine-granular data from more than 5000 active open source software projects we analyze the size of code contributions over a project’s life-span. Code contribution size has stayed flat. We interpret this to mean that open source software development has not changed its code integration practices. In particular, within the limits of this study, we claim that the practice of continuous integration has not yet significantly influenced the behavior of open source software developers.

Design and implementation of the Sweble Wikitext parser: unlocking the structured data of Wikipedia

The heart of each wiki, including Wikipedia, is its content. Most machine processing starts and ends with this content. At present, such processing is limited, because most wiki engines today cannot provide a complete and precise representation of the wikis content. They can only generate HTML. The main reason is the lack of well-defined parsers that can handle the complexity of modern wiki markup. This applies to Media Wiki, the software running Wikipedia, and most other wiki engines. This paper shows why it has been so difficult to develop comprehensive parsers for wiki markup. It presents the design and implementation of a parser for Wikitext, the wiki markup language of MediaWiki. We use parsing expression grammars where most parsers used no grammars or grammars poorly suited to the task. Using this parser it is possible to directly and precisely query the structured data within wikis, including Wikipedia. The parser is available as open source from http://sweble.org

A Model of Open Source Developer Foundations

Many community open source projects are of high economic relevance. As these projects mature, their leaders face a choice of continuing the project as is, making the project join an existing foundation, or creating their own foundation for the project. This article presents a model of open source developer foundations that project leaders can use to compare existing foundations with their needs or to design their own. The model is based on a three-iteration qualitative study involving interviews and supplementary materials review. To demonstrate its usefulness, we apply the model to nine foundations and present their organizational choices in a comparative table format.

Estimating Commit Sizes Efficiently

The quantitative analysis of software projects can provide insights that let us better understand open source and other software development projects. An important variable used in the analysis of software projects is the amount of work being contributed, the commit size. Unfortunately, post-facto, the commit size can only be estimated, not measured. This paper presents several algorithms for estimating the commit size. Our performance evaluation shows that simple, straightforward heuristics are superior to the more complex text-analysis-based algorithms. Not only are the heuristics significantly faster to compute, they also deliver more accurate results when estimating commit sizes. Based on this experience, we design and present an algorithm that improves on the heuristics, can be computed equally fast, and is more accurate than any of the prior approaches.

The comment density of open source software code

The development processes of open source software are different from traditional closed source development processes. Still, open source software is frequently of high quality. Thus, we are investigating how open source software creates high quality and whether it can maintain this quality for ever larger project sizes. In this paper, we look at one particular quality indicator, the density of comments in open source software code. In a large-scale study of more than 5,000 projects, we find that active open source projects document their source code, and we find that the comment density is independent of team and project size, but not of project age. In future work, we intend to correlate comment density with project success or failure.