Free software, Open source software, licenses.A short presentation including a procedure for research software and data dissemination

Free software, Open source software, licenses. A short presentation including a procedure for research software and data dissemination

1 Introduction

As H2020 approaches and open access policies spread in the European research community ([9]), it becomes more important to revisit the basic concepts in software distribution such as free software, open source software, licenses: they should be considered before any research software dissemination. We also propose here a distribution procedure that can be adapted for software and data dissemination.

The target public of this document is the research community at large. This document is at your disposal under the license CC-BY-SA v4.0, which means that it can be freely modified, but authors of modifications agree to keep the initial author information and state the changes made. Redistribution of this document or its modified version should be done under the same license terms. If you find this document useful, please make it available to a large public.

2 Definition of Free software

Free software has been first defined by the Free Software Foundation (FSF) created in 1985 by Richard M. Stallman, but free software was already available. Among well known examples there are TeX by Donald Knuth (1978) or the Berkeley Software Distribution (BSD) by the Computer Systems Research Group of the University of California (1977-1995).

This definition can be found on the page

“A program is free software if the program’s users have the four essential freedoms:

Freedom 0

The freedom to run the program as you wish, for any purpose.

Freedom 1

The freedom to study how the program works, and change it so it does your computing as you wish. Access to the source code is a precondition for this.

Freedom 2

The freedom to redistribute copies so you can help your neighbor.

Freedom 3

The freedom to distribute copies of your modified versions to others. By doing this you can give the whole community a chance to benefit from your changes. Access to the source code is a precondition for this.”

A program, code or software is free software because it is distributed respecting these four liberties. Just to say that a software is free means nothing, unless the above mentioned four liberties are (legally) insured through the license (called free software license) that comes with the software. If one liberty is missing the software cannot be free software, and it can be called proprietary software.

In our opinion, there still remains in some circles a misunderstanding related to the fourth liberty, therefore we would like to stress here that the distribution of modifications remains the choice of their author, and once redistribution is decided, it is necessary to verify that the reciprocity clauses of the initial software license are respected.

Note the importance of the word study in this definition, which was born in circles near research institutions. The FSF community states that only free software should be used in education. Our personal belief is that free software is particularly well adapted to the research environment and the way science evolves.

3 Definition of Open source software

By the end of the 90’s, the software community forked and the Open Source Initiative (OSI) was created in 1998 to define the concept of open source in the form of ten conditions. The full definition can be found on the page, and here we only sketch the main items.

“Open source doesn’t just mean access to the source code. The distribution terms of open-source software must comply with the following criteria:

  1. Free Redistribution
    The license shall not restrict any party from selling or giving away the software as a component of an aggregate software distribution containing programs from several different sources. The license shall not require a royalty or other fee for such sale.

  2. Source Code

  3. Derived Works

  4. Integrity of The Author’s Source Code

  5. No Discrimination Against Persons or Groups

  6. No Discrimination Against Fields of Endeavor

  7. Distribution of License

  8. License Must Not Be Specific to a Product

  9. License Must Not Restrict Other Software

  10. License Must Be Technology-Neutral”

We have included the full first item as it shows that this concept is closest to commercial interests rather than to liberty or to study goals. Again, a software is open source because the (open source) license that comes with the software respects these ten principles, and if one is missing, it is not open source software.

4 Differences, terminology, licenses

These two definitions correspond to (very) different philosophies, but in fact most software we are talking about here is at the same time free and open source, as the most commonly used licenses verify the conditions of both definitions. In legal terms, free and/or open source licenses are contracts and contribute to the legal framework where one is allowed to use, copy, modify, and redistribute the software. Free or open source software is not “free of rights”, author’s rights are not going to disappear because a software is free or open source. In fact, the licenses extend the initial legal frame stated by the law (copyright law, code de la propriété intellectuelle, derechos de autor…).

Nevertheless there are examples of software which is open source but not free, we mention here two kind of examples.

Some more terminology: commercial software is software with a license that requires a financial counterpart. Free and open source software can be commercial, free doesn’t always mean gratis2 and the opposite also applies: gratis doesn’t always correspond to free or open source software. Software distributed with source code is not always free or open source. Software distributed without a license is not free nor open source, it is all rights reserved.

There are also members of the software community who use the terminology of Free/Open Source Software (FOSS) or Free/Libre/Open Source Software (FLOSS) (where libre remains in French or Spanish to stress the liberty side of the word free) because they prefer not to choose between the two definitions.

5 A classification of free/open source licenses

Licenses give rights (and liberties) but also have reciprocity clauses to be respected, as for example not to give the initial name to a modified version, or the requirement to cite some work or publication. Here we give a classification extracted from “A Practical Guide …” by T. Aimé ([5], p.9, see also [6]).

  • the initial software license of A is inherited in software A’ (without regarding if it has been modified) and new linked components B. The reciprocity clause indicates that the initial license remains at the distribution of the modified software. Well known examples are GNU GPL and the French CeCILL v2.

  • the initial software license of A remains in A or its modified version A’, but new software components may have any license. For example see licenses MPL, GNU LGPL, CeCILL-C.

  • the initial software license of A can disappear in A’ (without regarding if it has been modified) and new components can have any kind of license. For example see licenses Apache, BSD, MIT, CeCILL-B.

Table 1: A classification of licenses.

Because of its impact, we quote here the GPLv2 phrase that activates license inheritance: “You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License.”

Beware of possible conflicting obligations imposed by licenses when including and modifying a lot of software components to build a new one. You can find here the FSF license compatibility table:

6 The double rôle of licenses

On the one hand, licenses establish the legal framework3 in which it is allowed to use, copy, modify, and redistribute software. In France, law indicates that it is illegal to use or to modify software unless you have a (written) agreement to do so (see [5], p.3). Giving access to software in web pages does not produce free nor open source software, nor legally useable software: it is important to establish a license. Free and open source licenses give a legal frame “by default”, and if it is not convenient for the use or support you need, you can contact authors to establish other kind of collaborations (usually by paying more services).

On the other hand, when the use of licenses such as free software licenses is decided at the level of head institutions, laboratories or research funding agencies, when they are required in documents such as the Berlin declaration ([4])4, this corresponds to strong policies where free access to the research production is at stake, having as consequence, for example, to increase the reproductibility of research.

The word open has quickly expanded beyond the software limits, we are now in the world of open access, open education, open innovation, open data, … and even open government. It has become also a fancy word and it can appear in contexts not “open” at all; please be careful and check definitions, licenses, policies.

7 A distribution procedure for research software or data

The following list of steps can be adapted in order to create a distribution procedure for research software (see [7]). It can also be adapted to distribute research data. Steps marked with (*) are to be revisited regularly in each version release.

  • Choose a name or title to identify the object, avoid trademarks and other proprietary names, you can associate date, version number, target platform…

  • (*) Establish the list of authors and affiliations. An associated percentage of participation, completed with minor contributors can be useful. If the list is too long, keep updated information in a web page.

  • (*) Establish the list of main functionalities.

  • (*) Establish the list of included software and data components, indicate their licenses or other documents giving right to access, copy, modification, redistribution for the component.

  • Choose a license, with the agreement of all the rights’ holders and authors, have a signed agreement if possible. Consider using free software licenses and CC licenses (v4.0) for data (for example).

  • Choose a web site, forge, or deposit to distribute your product; licensing and conditions of use, copy, modification, and/or redistribution should be clearly stated, as well as the best way to cite your work. Good metadata and respect of open standards are always important when giving away new components to a large community: it helps others to use your work and increases its longevity. Give licenses to the documentation (GNU FDL, CC, LAL…) and to web sites. Use persistent identifiers if possible.

  • (*) In order to help tracking new important functionalities, archive a tar.gz or similar in safe place.

  • Inform your laboratories and head institutions (if this has not be done in the license step).

  • Create and indicate clearly an adress of contact.

  • Distribute the software or data component.

  • Inform the community.

How to give a license.

To install a license is not a difficult step, but it should be done before distributing the software. The basic idea is to identify the files with a commented heading including the important informations about authors, dates, licenses, and to add to the whole set of files an additional file including the text of the license (or a link to a web page with it) in a file named COPYING, LICENCE or README for example. Please indicate the license in the documentation, in the web site, as well as the authors and their affiliations. Here is an example for the headings:

  • name: name of the file, name and version of the software,

  • holder of rights: Copyright (©), year(s), head institutions, persons…

  • authors: the list of authors and their institutions (or a link if it is too long),

  • license: name and version,

  • dates: creation date, last modification date.

8 Conclusion

The main goal of this document is to help the research community to understand the basic concepts of software distribution and the associated licenses. If you think that this document is useful in this respect, please help distributing this document to a wider audience.

Acknowledgements. With many thanks to proofreaders of previous versions of this document.


  1. For more information you can see
  2. Free can translate as gratis in Spanish or gratuit in French, which is very different from libre.
  3. Modification of any legal information (authors, institutions, dates, licenses…) in components gathered on the net should be avoided.
  4. See also the Budapest Open Acces Initiative ([3]), where licenses are not mentioned, but are suggested: “… permitting any users to read, download, copy, distribute, print, search, or link, …


  1. Free Software Foundation,
  2. Open Source Initiative,
  3. Budapest Open Access Initiative, 2002,
  4. Berlin Declaration on Open Access to Knowledge in the Sciences and Humanities, 2003,
  5. A Practical Guide to Using Free Software in the Public Sector, T. Aimé, 2010, PDF file available from
  6. Licence & copyright pour les développements de logiciels libres de laboratoires de recherche, T. Gomez-Diaz, 2009,
  7. Diffuser un logiciel de laboratoire : recommandations juridiques et administratives, T. Gomez-Diaz, 2010,
  8. Thème PLUME: “Patrimoine logiciel d’un laboratoire”,
  9. Towards better access to scientific information: Boosting the benefits of public investments in research, European Commission, 2012,
    Background page:
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