Open Source, Modular Platforms, and the Challenge of Fragmentation

45 Pages Posted: 10 Nov 2016 Last revised: 11 Nov 2016

See all articles by Christopher S. Yoo

Christopher S. Yoo

University of Pennsylvania Law School; University of Pennsylvania - Annenberg School for Communication; University of Pennsylvania - School of Engineering and Applied Science

Date Written: November 7, 2016


Open source and modular platforms represent two powerful conceptual paradigms that have fundamentally transformed the software industry. While generally regarded complementary, the freedom inherent in open source rests in uneasy tension with the strict structural requirements required by modularity theory. In particular, third party providers can produce noncompliant components, and excessive experimentation can fragment the platform in ways that reduce its economic benefits for end users and app providers and force app providers to spend resources customizing their code for each variant. The classic solutions to these problems are to rely on some form of testing to ensure that the components provided by third parties comply with a compatibility standard and to subject the overall system to some form of governance. The history of the three leading open source operating systems (Unix, Symbian, and Linux) confirms this insight. The question is thus not whether some constraints will apply, but rather how restrictive those constraints will be. Finally, the governance regimes range from very restrictive to relatively open and permissive. Competition policy authorities should take into account where certain practices fall along that spectrum when enforcing competition law. Exposing the more permissive practices to demanding scrutiny runs the risk of causing operating systems to turn to more restrictive approaches.

Keywords: Platforms, open source software, modular systems, innovation, compatibility standards, non-compliant modules, fragmentation, forking, Unix, Symbian, Linux, Android, smart phones, smartphone operating systems, testing, integration, anti-fragmentation agreement (AFA), governance

JEL Classification: K21, K23, L40, L86, O31, O33, O38

Suggested Citation

Yoo, Christopher S., Open Source, Modular Platforms, and the Challenge of Fragmentation (November 7, 2016). U of Penn, Inst for Law & Econ Research Paper No. 16-29. Available at SSRN: or

Christopher S. Yoo (Contact Author)

University of Pennsylvania Law School ( email )

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University of Pennsylvania - Annenberg School for Communication ( email )

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University of Pennsylvania - School of Engineering and Applied Science ( email )

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