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What Do We Really Know About Fortran?

Authors Austen Rainer , Andrew Brown , Rebecca Taylor , Simon Hettrick

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Document Identifiers

Subject Classification

ACM Subject Classification
  • Software and its engineering
  • Applied computing → Physical sciences and engineering
  • Social and professional topics
Keywords
  • Fortran
  • demographics
  • software engineering
  • research software engineer
  • computational scientist
  • software sustainability

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Abstract

Background. Anecdotal evidence suggests that the Fortran ecosystem - the language, tooling, codebases and broad community - continues to make a significant international contribution to science and engineering. Yet the common perception appears to be that Fortran is old and obsolete and, as a result, one should divest from it. There is no empirical evidence - e.g., no contemporary or historical survey - to corroborate or contradict such perception. A consequence is that this perception may be not only mistaken but also damaging to the Fortran ecosystem and to the global contribution that the ecosystem continues to make to society, the economy and environment. 

Aims. To gather empirical evidence on the current state of the global Fortran ecosystem, in order to corroborate or challenge perceptions about the language, tooling, codebases and community. 

Method. We conduct an international survey of the Fortran community, collecting information from 150 respondents across 25 countries. 

Results. We report results about codebases (e.g. code size varies from 1KLOC to 5MLOC), community demographics (e.g., most respondents are male; most respondents hold doctorates), challenges (e.g., code complexity, human resource) and perceptions of Fortran (only 15% consider their codebases to be legacy codebases). 

Conclusions. Our results provide the first descriptive benchmark of the Fortran ecosystem which can act as a resource or reference for future research and practice. Also, our results suggest that Fortran may be better understood as a highly-valuable, niche, contemporary ecosystem, one which continues to contribute to world-leading research in many science and engineering disciplines. As an "edge case", it is ideally placed to provide unique and insightful contributions to our understanding of (scientific) software engineering, e.g., technical debt, refactoring, code complexity, and the significance of application domain knowledge. Since all codebases, regardless of language, have the potential to become legacy systems in the future, Fortran is actually at the forefront of confronting long-term challenges and consequences of engineering complex (scientific) software systems.

Cite As Get BibTex

Austen Rainer, Andrew Brown, Rebecca Taylor, and Simon Hettrick. What Do We Really Know About Fortran?. In 20th International Symposium on Empirical Software Engineering and Measurement (ESEM 2026). Leibniz International Proceedings in Informatics (LIPIcs), Volume 394, pp. 16:1-16:20, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2026) https://doi.org/10.4230/LIPIcs.ESEM.2026.16

Author Details

Austen Rainer
  • Queen’s University Belfast, UK
Andrew Brown
  • Queen’s University Belfast, UK
Rebecca Taylor
  • University of Southampton, England
Simon Hettrick
  • University of Southampton, England

Funding

The work of all authors is supported by grant UKRI4343 FortranFuture: a Network for Sustainable Fortran-based Science from the UK’s Engineering and Physical Sciences Research Council (EPSRC).
  • Brown, Andrew: EPSRC grant EP/V05208X/1
  • Hettrick, Simon: AHRC grant AH/Z000114/1

Acknowledgements

We thank those who piloted the survey, and all 150 survey participants, including the following respondents who chose to identify themselves: AdAstraPerAspera, Amir Shahmoradi, Amy Roberts, Anon77, An RSE from a Helmholtz research institute in Germany, ariiJudeIS, BiathlonFan, Boteh, CabraLattice, CampanologicalToxophilite, CampFire, CJM, CLaSSGroupLead, cmaapic, CoolFortran, Dalekopera, dmio7839r, DogCatMouse, DrFortranFan, dwa, ForProfit, FortranIsStillMyFavorite, FortranKPDH, Fotranista123BEva, FragmentedEchidna, Gaits, Gideon, GOTO_EndOfSurvey, GoTo_remover, HerbertPeck, hjf, ibperth, IndAtHomeFort18, InTartifletteWeTrust, jasNW, "Keeping people and society safe", lsm, Machalot, Martin Diehl, mathemagician, Milan Skocic, Modeller2026, mwatkins, NumberCrunching4QD, OldCrustyAstroGuy, otisthecat, paleoprogrammer, Partecipant 21, ParticipantJad, PDS, PH, Phoenix, platipodium, Polis, PRIMA, RSEwithAGPL, SelaBuri, Simulacrum, T3, TNT, upg88743, yarchik.

Supplementary Materials

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