Corporate Truck Factor: Firm-Level Knowledge Concentration in Linux Kernel Subsystems
Resumo
Knowledge concentration in Free/Libre and Open Source Software (FLOSS) is usually measured per developer, through metrics such as the Truck Factor. However, paid employees write most of the Linux Kernel code, so one company’s departure can leave behind far more knowledge than any per-developer metric would reveal.We present a firm-level, token-based concentration model that joins token authorship from the cregit tool with e-mail-domain-to-company resolution, market-concentration metrics from economics, and our proposed corporate Truck Factor, across three Linux subsystems (amdgpu, net, and iio), chosen to span known regimes. Counting by firm rather than by person exposes an employment fold: authorship that looks broadly shared among individuals collapses onto a few employers. The starkest case is amdgpu: by individual Truck Factor, it looks safer than iio (35 individuals against 31), yet by firm, it is the most fragile of the three (1 company), a reversal that only the firm-level view makes measurable.
Palavras-chave:
Truck Factor, Knowledge Concentration, Company Contributions, Linux Kernel, Free Software, Mining Software Repositories
Referências
M. A. Adelman. 1969. Comment on the “H” Concentration Measure as a NumbersEquivalent. The Review of Economics and Statistics 51, 1 (1969), 99–101. DOI: 10.2307/1926955
Guilherme Avelino, Leonardo Passos, Andre Hora, and Marco Tulio Valente. 2016. A Novel Approach for Estimating Truck Factors. In Proceedings of the 24th IEEE International Conference on Program Comprehension (ICPC). 1–10. DOI: 10.1109/ICPC.2016.7503718
Guilherme Avelino, Leonardo Passos, Andre Hora, and Marco Tulio Valente. 2017. Assessing Code Authorship: The Case of the Linux Kernel. InOpen Source Systems: Towards Robust Practices (OSS 2017), IFIP AICT 496. 151–163. DOI: 10.1007/978-3-319-57735-7_15
Elizabeth Barron, Matt Germonprez, Kevin Lumbard, Yash Prakash, Georg Link, andMaalik Peculiar C. Umeh. 2026.Metric: Elephant Factor. CHAOSS (Community Health Analytics Open Source Software). [link] A Linux Foundation project. Accessed on Aug 10th 2026..
Kent Beck and Cynthia Andres. 2004. Extreme Programming Explained: Embrace Change (2nd ed.). Addison-Wesley.
Christian Bird, Nachiappan Nagappan, Brendan Murphy, Harald Gall, and Premkumar Devanbu. 2011. Don’t Touch My Code! Examining the Effects of Ownership on Software Quality. In Proceedings of the 19th ACM SIGSOFT Symposium and the 13th European Conference on Foundations of Software Engineering (ESEC/FSE). 4–14. DOI: 10.1145/2025113.2025119
Jonathan Corbet. [n. d.]. gitdm: The “git data miner”. [link]. Affiliation via a domain-to-employer EmailMap, with per-developer user@domain overrides and dated entries for developers who keep personal e-mail across employers.
Jonathan Corbet and Greg Kroah-Hartman. 2017. 2017 Linux Kernel Development Report. Technical Report. The Linux Foundation.
Valerio Cosentino, Javier Luis Cánovas Izquierdo, and Jordi Cabot. 2015. Assessing the Bus Factor of Git Repositories. In Proceedings of the 22nd IEEE International Conference on Software Analysis, Evolution, and Reengineering (SANER). 499–503. DOI: 10.1109/SANER.2015.7081864
Otávio Cury and Guilherme Avelino. 2024. Knowledge Islands: Visualizing Developers’ Knowledge Concentration. In Anais do XXXVIII Simpósio Brasileiro de Engenharia de Software (SBES). SBC, 789–795. DOI: 10.5753/sbes.2024.3610
Ahmed El Cheikh Ammar, Sukru Eraslan, and Yeliz Yesilada. 2025. Predicting the Truck Factor in a Software Repository Using Machine Learning. Information and Software Technology 184 (2025), 107765. DOI: 10.1016/j.infsof.2025.107765
Mivian Ferreira, Thaís Mombach, Marco Tulio Valente, and Kecia Ferreira. 2019. Algorithms for Estimating Truck Factors: A Comparative Study. Software Quality Journal 27, 4 (2019), 1583–1617. DOI: 10.1007/s11219-019-09457-2
Mivian Ferreira, Marco Tulio Valente, and Kecia Ferreira. 2017. A Comparison of Three Algorithms for Computing Truck Factors. In Proceedings of the 25th IEEE International Conference on Program Comprehension (ICPC). 207–217. DOI: 10.1109/ICPC.2017.35
Daniel M. German, Bram Adams, and Kate Stewart. 2019. cregit: Token-Level Blame Information in Git Version Control Repositories. Empirical Software Engineering 24, 4 (2019), 2725–2763. DOI: 10.1007/s10664-019-09704-x
Corrado Gini. 1912. Variabilità e Mutabilità: Contributo allo Studio delle Distribuzioni e delle Relazioni Statistiche. Tipografia di Paolo Cuppini, Bologna.
Orris C. Herfindahl. 1950. Concentration in the Steel Industry. PhD dissertation, Columbia University.
Albert O. Hirschman. 1964. The Paternity of an Index. The American Economic Review 54, 5 (1964), 761–762.
Giuseppe Iaffaldano, Igor Steinmacher, Fabio Calefato, Marco Gerosa, and Filippo Lanubile. 2019. Why Do Developers Take Breaks from Contributing to OSS Projects? A Preliminary Analysis. arXiv:1903.09528 [cs.SE]
Elgun Jabrayilzade, Mikhail Evtikhiev, Eray Tüzün, and Vladimir Kovalenko. 2022. Bus Factor in Practice. In Proceedings of the 44th International Conference on Software Engineering: Software Engineering in Practice (ICSE-SEIP). 97–106. DOI: 10.1145/3510457.3513082
Xuetao Li, Yuxia Zhang, Cailean Osborne, Minghui Zhou, Zhi Jin, and Hui Liu. 2025. A Systematic Literature Review of Commercial Participation in Open Source Software. ACM Transactions on Software Engineering and Methodology (TOSEM) 34, 2, Article 33 (2025), 31 pages. DOI: 10.1145/3690632
M. O. Lorenz. 1905. Methods of Measuring the Concentration of Wealth. Publications of the American Statistical Association 9, 70 (1905), 209–219. DOI: 10.2307/2276207
Courtney Miller, David Gray Widder, Christian Kästner, and Bogdan Vasilescu. 2019. Why Do People Give Up FLOSSing? A Study of Contributor Disengagement in Open Source. In Open Source Systems (OSS 2019), IFIP AICT 556. 116–129. DOI: 10.1007/978-3-030-20883-7_11
Mathieu Nassif and Martin P. Robillard. 2017. Revisiting Turnover-Induced Knowledge Loss in Software Projects. In Proceedings of the 33rd IEEE International Conference on Software Maintenance and Evolution (ICSME). 261–272. DOI: 10.1109/ICSME.2017.64
Brigitta Németh and Johannes Wachs. 2025. Anchor Sponsor Firms in Open Source Software Ecosystems. arXiv:2502.09060 [cs.SE]
Anh Nguyen-Duc, Daniela S. Cruzes, Terje Snarby, and Pekka Abrahamsson. 2019. Do Software Firms Collaborate or Compete? A Model of Coopetition in Community-Initiated OSS Projects. e-Informatica Software Engineering Journal 13, 1 (2019), 37–62. DOI: 10.5277/e-Inf190102
Olivier Nourry, Masanari Kondo, Shinobu Saito, Yukako Iimura, Naoyasu Ubayashi, and Yasutaka Kamei. 2024. Myth: The Loss of Core Developers Is a Critical Issue for OSS Communities. arXiv:2412.00313 [cs.SE]
Dirk Riehle, Philipp Riemer, Carsten Kolassa, and Michael Schmidt. 2014. Paid vs. Volunteer Work in Open Source. In Proceedings of the 47th Hawaii International Conference on System Sciences (HICSS). IEEE, 3286–3295. DOI: 10.1109/HICSS.2014.407
Peter C. Rigby, Yue Cai Zhu, Samuel M. Donadelli, and Audris Mockus. 2016. Quantifying and Mitigating Turnover-Induced Knowledge Loss: Case Studies of Chrome and a Project at Avaya. In Proceedings of the 38th International Conference on Software Engineering (ICSE). 1006–1016. DOI: 10.1145/2884781.2884851
Roland Robert Schreiber and Thomas Wieland. 2026. Inter-organizational Collaborations in Open-Source Software Ecosystems. Journal of Systems and Software 235 (2026), 112765. DOI: 10.1016/j.jss.2025.112765
Diomidis Spinellis, Zoe Kotti, Konstantinos Kravvaritis, Georgios Theodorou, and Panos Louridas. 2020. A Dataset of Enterprise-Driven Open Source Software. In Proceedings of the 17th International Conference on Mining Software Repositories (MSR). 533–537. DOI: 10.1145/3379597.3387495
Yuxia Zhang, Hao He, and Minghui Zhou. 2022. Commercial Participation in OpenStack: Two Sides of a Coin. Computer 55, 2 (2022), 78–84. DOI: 10.1109/MC.2021.3133052
Yuxia Zhang, Hui Liu, Xin Tan, Minghui Zhou, Zhi Jin, and Jiaxin Zhu. 2022. Turnover of Companies in OpenStack: Prevalence and Rationale. ACM Transactions on Software Engineering and Methodology (TOSEM) 31, 4, Article 75 (2022), 24 pages. DOI: 10.1145/3510849
Yuxia Zhang, Mian Qin, Klaas-Jan Stol, Minghui Zhou, and Hui Liu. 2024. How Are Paid and Volunteer Open Source Developers Different? A Study of the Rust Project. In Proceedings of the 46th International Conference on Software Engineering (ICSE). 195:1–195:13. DOI: 10.1145/3597503.3639197
Yuxia Zhang, Klaas-Jan Stol, Hui Liu, and Minghui Zhou. 2022. Corporate Dominance in Open Source Ecosystems: A Case Study of OpenStack. In Proceedings of the 30th ACM Joint European Software Engineering Conference and Symposium on the Foundations of Software Engineering (ESEC/FSE). 1048–1060. DOI: 10.1145/3540250.3549117
Yuxia Zhang, Xin Tan, Minghui Zhou, and Zhi Jin. 2018. Companies’ Domination in FLOSS Development: An Empirical Study of OpenStack. In Proceedings of the 40th International Conference on Software Engineering: Companion (ICSE Companion). 440–441. DOI: 10.1145/3183440.3195047
Yuxia Zhang, Minghui Zhou, Audris Mockus, and Zhi Jin. 2021. Companies’ Participation in OSS Development: An Empirical Study of OpenStack. IEEE Transactions on Software Engineering 47, 10 (2021), 2242–2259. DOI: 10.1109/TSE.2019.2946156
Yuxia Zhang, Minghui Zhou, Klaas-Jan Stol, Jianyu Wu, and Zhi Jin. 2020. How Do Companies Collaborate in Open Source Ecosystems? An Empirical Study of OpenStack. In Proceedings of the 42nd International Conference on Software Engineering (ICSE). 1196–1208. DOI: 10.1145/3377811.3380376
Guilherme Avelino, Leonardo Passos, Andre Hora, and Marco Tulio Valente. 2016. A Novel Approach for Estimating Truck Factors. In Proceedings of the 24th IEEE International Conference on Program Comprehension (ICPC). 1–10. DOI: 10.1109/ICPC.2016.7503718
Guilherme Avelino, Leonardo Passos, Andre Hora, and Marco Tulio Valente. 2017. Assessing Code Authorship: The Case of the Linux Kernel. InOpen Source Systems: Towards Robust Practices (OSS 2017), IFIP AICT 496. 151–163. DOI: 10.1007/978-3-319-57735-7_15
Elizabeth Barron, Matt Germonprez, Kevin Lumbard, Yash Prakash, Georg Link, andMaalik Peculiar C. Umeh. 2026.Metric: Elephant Factor. CHAOSS (Community Health Analytics Open Source Software). [link] A Linux Foundation project. Accessed on Aug 10th 2026..
Kent Beck and Cynthia Andres. 2004. Extreme Programming Explained: Embrace Change (2nd ed.). Addison-Wesley.
Christian Bird, Nachiappan Nagappan, Brendan Murphy, Harald Gall, and Premkumar Devanbu. 2011. Don’t Touch My Code! Examining the Effects of Ownership on Software Quality. In Proceedings of the 19th ACM SIGSOFT Symposium and the 13th European Conference on Foundations of Software Engineering (ESEC/FSE). 4–14. DOI: 10.1145/2025113.2025119
Jonathan Corbet. [n. d.]. gitdm: The “git data miner”. [link]. Affiliation via a domain-to-employer EmailMap, with per-developer user@domain overrides and dated entries for developers who keep personal e-mail across employers.
Jonathan Corbet and Greg Kroah-Hartman. 2017. 2017 Linux Kernel Development Report. Technical Report. The Linux Foundation.
Valerio Cosentino, Javier Luis Cánovas Izquierdo, and Jordi Cabot. 2015. Assessing the Bus Factor of Git Repositories. In Proceedings of the 22nd IEEE International Conference on Software Analysis, Evolution, and Reengineering (SANER). 499–503. DOI: 10.1109/SANER.2015.7081864
Otávio Cury and Guilherme Avelino. 2024. Knowledge Islands: Visualizing Developers’ Knowledge Concentration. In Anais do XXXVIII Simpósio Brasileiro de Engenharia de Software (SBES). SBC, 789–795. DOI: 10.5753/sbes.2024.3610
Ahmed El Cheikh Ammar, Sukru Eraslan, and Yeliz Yesilada. 2025. Predicting the Truck Factor in a Software Repository Using Machine Learning. Information and Software Technology 184 (2025), 107765. DOI: 10.1016/j.infsof.2025.107765
Mivian Ferreira, Thaís Mombach, Marco Tulio Valente, and Kecia Ferreira. 2019. Algorithms for Estimating Truck Factors: A Comparative Study. Software Quality Journal 27, 4 (2019), 1583–1617. DOI: 10.1007/s11219-019-09457-2
Mivian Ferreira, Marco Tulio Valente, and Kecia Ferreira. 2017. A Comparison of Three Algorithms for Computing Truck Factors. In Proceedings of the 25th IEEE International Conference on Program Comprehension (ICPC). 207–217. DOI: 10.1109/ICPC.2017.35
Daniel M. German, Bram Adams, and Kate Stewart. 2019. cregit: Token-Level Blame Information in Git Version Control Repositories. Empirical Software Engineering 24, 4 (2019), 2725–2763. DOI: 10.1007/s10664-019-09704-x
Corrado Gini. 1912. Variabilità e Mutabilità: Contributo allo Studio delle Distribuzioni e delle Relazioni Statistiche. Tipografia di Paolo Cuppini, Bologna.
Orris C. Herfindahl. 1950. Concentration in the Steel Industry. PhD dissertation, Columbia University.
Albert O. Hirschman. 1964. The Paternity of an Index. The American Economic Review 54, 5 (1964), 761–762.
Giuseppe Iaffaldano, Igor Steinmacher, Fabio Calefato, Marco Gerosa, and Filippo Lanubile. 2019. Why Do Developers Take Breaks from Contributing to OSS Projects? A Preliminary Analysis. arXiv:1903.09528 [cs.SE]
Elgun Jabrayilzade, Mikhail Evtikhiev, Eray Tüzün, and Vladimir Kovalenko. 2022. Bus Factor in Practice. In Proceedings of the 44th International Conference on Software Engineering: Software Engineering in Practice (ICSE-SEIP). 97–106. DOI: 10.1145/3510457.3513082
Xuetao Li, Yuxia Zhang, Cailean Osborne, Minghui Zhou, Zhi Jin, and Hui Liu. 2025. A Systematic Literature Review of Commercial Participation in Open Source Software. ACM Transactions on Software Engineering and Methodology (TOSEM) 34, 2, Article 33 (2025), 31 pages. DOI: 10.1145/3690632
M. O. Lorenz. 1905. Methods of Measuring the Concentration of Wealth. Publications of the American Statistical Association 9, 70 (1905), 209–219. DOI: 10.2307/2276207
Courtney Miller, David Gray Widder, Christian Kästner, and Bogdan Vasilescu. 2019. Why Do People Give Up FLOSSing? A Study of Contributor Disengagement in Open Source. In Open Source Systems (OSS 2019), IFIP AICT 556. 116–129. DOI: 10.1007/978-3-030-20883-7_11
Mathieu Nassif and Martin P. Robillard. 2017. Revisiting Turnover-Induced Knowledge Loss in Software Projects. In Proceedings of the 33rd IEEE International Conference on Software Maintenance and Evolution (ICSME). 261–272. DOI: 10.1109/ICSME.2017.64
Brigitta Németh and Johannes Wachs. 2025. Anchor Sponsor Firms in Open Source Software Ecosystems. arXiv:2502.09060 [cs.SE]
Anh Nguyen-Duc, Daniela S. Cruzes, Terje Snarby, and Pekka Abrahamsson. 2019. Do Software Firms Collaborate or Compete? A Model of Coopetition in Community-Initiated OSS Projects. e-Informatica Software Engineering Journal 13, 1 (2019), 37–62. DOI: 10.5277/e-Inf190102
Olivier Nourry, Masanari Kondo, Shinobu Saito, Yukako Iimura, Naoyasu Ubayashi, and Yasutaka Kamei. 2024. Myth: The Loss of Core Developers Is a Critical Issue for OSS Communities. arXiv:2412.00313 [cs.SE]
Dirk Riehle, Philipp Riemer, Carsten Kolassa, and Michael Schmidt. 2014. Paid vs. Volunteer Work in Open Source. In Proceedings of the 47th Hawaii International Conference on System Sciences (HICSS). IEEE, 3286–3295. DOI: 10.1109/HICSS.2014.407
Peter C. Rigby, Yue Cai Zhu, Samuel M. Donadelli, and Audris Mockus. 2016. Quantifying and Mitigating Turnover-Induced Knowledge Loss: Case Studies of Chrome and a Project at Avaya. In Proceedings of the 38th International Conference on Software Engineering (ICSE). 1006–1016. DOI: 10.1145/2884781.2884851
Roland Robert Schreiber and Thomas Wieland. 2026. Inter-organizational Collaborations in Open-Source Software Ecosystems. Journal of Systems and Software 235 (2026), 112765. DOI: 10.1016/j.jss.2025.112765
Diomidis Spinellis, Zoe Kotti, Konstantinos Kravvaritis, Georgios Theodorou, and Panos Louridas. 2020. A Dataset of Enterprise-Driven Open Source Software. In Proceedings of the 17th International Conference on Mining Software Repositories (MSR). 533–537. DOI: 10.1145/3379597.3387495
Yuxia Zhang, Hao He, and Minghui Zhou. 2022. Commercial Participation in OpenStack: Two Sides of a Coin. Computer 55, 2 (2022), 78–84. DOI: 10.1109/MC.2021.3133052
Yuxia Zhang, Hui Liu, Xin Tan, Minghui Zhou, Zhi Jin, and Jiaxin Zhu. 2022. Turnover of Companies in OpenStack: Prevalence and Rationale. ACM Transactions on Software Engineering and Methodology (TOSEM) 31, 4, Article 75 (2022), 24 pages. DOI: 10.1145/3510849
Yuxia Zhang, Mian Qin, Klaas-Jan Stol, Minghui Zhou, and Hui Liu. 2024. How Are Paid and Volunteer Open Source Developers Different? A Study of the Rust Project. In Proceedings of the 46th International Conference on Software Engineering (ICSE). 195:1–195:13. DOI: 10.1145/3597503.3639197
Yuxia Zhang, Klaas-Jan Stol, Hui Liu, and Minghui Zhou. 2022. Corporate Dominance in Open Source Ecosystems: A Case Study of OpenStack. In Proceedings of the 30th ACM Joint European Software Engineering Conference and Symposium on the Foundations of Software Engineering (ESEC/FSE). 1048–1060. DOI: 10.1145/3540250.3549117
Yuxia Zhang, Xin Tan, Minghui Zhou, and Zhi Jin. 2018. Companies’ Domination in FLOSS Development: An Empirical Study of OpenStack. In Proceedings of the 40th International Conference on Software Engineering: Companion (ICSE Companion). 440–441. DOI: 10.1145/3183440.3195047
Yuxia Zhang, Minghui Zhou, Audris Mockus, and Zhi Jin. 2021. Companies’ Participation in OSS Development: An Empirical Study of OpenStack. IEEE Transactions on Software Engineering 47, 10 (2021), 2242–2259. DOI: 10.1109/TSE.2019.2946156
Yuxia Zhang, Minghui Zhou, Klaas-Jan Stol, Jianyu Wu, and Zhi Jin. 2020. How Do Companies Collaborate in Open Source Ecosystems? An Empirical Study of OpenStack. In Proceedings of the 42nd International Conference on Software Engineering (ICSE). 1196–1208. DOI: 10.1145/3377811.3380376
Publicado
11/09/2026
Como Citar
COSTA, Ellian Carlos; LAGROTARIA, Gabriel Braga; KOJO, Ricardo Hideki Hangai; PILONE, Arthur; MEIRELLES, Paulo.
Corporate Truck Factor: Firm-Level Knowledge Concentration in Linux Kernel Subsystems. In: WORKSHOP DE VISUALIZAÇÃO, EVOLUÇÃO E MANUTENÇÃO DE SOFTWARE (VEM), 14. , 2026, São Paulo/SP.
Anais [...].
Porto Alegre: Sociedade Brasileira de Computação,
2026
.
p. 204-208.
DOI: https://doi.org/10.5753/vem.2026.33016.
