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Cited by 1,685Open Source Software InnovationsSoftware Engineering Techniques and PracticesSoftware Engineering Research

Two case studies of open source software development: Apache and Mozilla

Mockus, Audris, Fielding, Roy T., Herbsleb, James D.·2002·ACM Transactions on Software Engineering and Methodology
DOI 10.1145/567793.567795
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Abstract

According to its proponents, open source style software development has the capacity to compete successfully, and perhaps in many cases displace, traditional commercial development methods. In order to begin investigating such claims, we examine data from two major open source projects, the Apache web server and the Mozilla browser. By using email archives of source code change history and problem reports we quantify aspects of developer participation, core team size, code ownership, productivity, defect density, and problem resolution intervals for these OSS projects. We develop several hypotheses by comparing the Apache project with several commercial projects. We then test and refine several of these hypotheses, based on an analysis of Mozilla data. We conclude with thoughts about the prospects for high-performance commercial/open source process hybrids.

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  • 87% of the Apache members who reported bugs submitted just one report.

    “Mockus et al. (2002) estimate that 87% of the Apache members who reported bugs submitted just one report.”

    From Open Source Software: The New Intellectual Property Paradigm (2006) · cites this paper as Mockus et al. (2002)

  • 15 core developers provide 83% of all Apache contributions.

    “Similarly, Mockus et al. (2002) tell us that 15 core developers provide 83% of all Apache contributions while Von Krogh et al . (2003) report that about one percent of Freenet's members account for fifty percent of all developer e-mails.”

    From Open Source Software: The New Intellectual Property Paradigm (2006) · cites this paper as Mockus et al. (2002)

  • Participation models such as the onion model and the core-periphery model become less hierarchical and more situational, as members can be peripheral in times of stability but become central agents during times of instability.

    “Accordingly, participation models such as the onion model (Nakakoji et al. 2002;Crowston and Howison 2005) and the core-periphery model (Mockus et al. 2002;Crowston et al. 2006) become less hierarchical and more situational, as members can be in peripheral positions in times of stability but become central agents during times of instability.”

    From Freeriding and Rebellion: An Investigation of Open Source Vendor Relicensing and Member Hard Forking Events (2026) · cites this paper as Mockus et al. 2002

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Authors
Mockus, A., Fielding, R. T., & Herbsleb, J. D.
Affiliations
  • Avaya (United States) (US)
  • Day Software, Newport Beach, CA
  • Carnegie Mellon University (US)
ORCID
Venue
ACM Transactions on Software Engineering and Methodology
Publisher
Association for Computing Machinery (ACM)
Published
2002-07
Volume
11
Issue
3
Pages
309-346
ISSN
  • 1049-331X (ISSN-L)
  • 1557-7392
DOI
10.1145/567793.567795
OpenAlex
W2107294940
Cited by
1,685
References
1
Citations by year
2026: 34 · 2025: 41 · 2024: 39 · 2023: 35 · 2022: 27 · 2021: 36 · 2020: 49 · 2019: 48 · 2018: 61 · 2017: 64 · 2016: 66 · 2015: 76 · 2014: 109 · 2013: 107 · 2012: 112
FWCI
108.28
Type
journal article
Language
en
Open access
closed
Licence
www.acm.org/publications/policies/copyright_policy#Background (vor)
Locations
ACM Transactions on Software Engineering and Methodology (publishedVersion)
Topics
  • Physical Sciences › Computer Science › Computer Science Applications › Open Source Software Innovations
  • Physical Sciences › Computer Science › Information Systems › Software Engineering Techniques and Practices
  • Physical Sciences › Computer Science › Information Systems › Software Engineering Research
Keywords
open source software development, Apache web server, developer engagement, code ownership, developer productivity, defect density, commercial software development

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