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Licensing recommendations

CERN's Open Science Policy Implementation Plan mandates that "CERN software is made available as open source wherever possible". The choice of license for a project should be done in consultation with the relevant CERN body: for software the OSPO, and for hardware the Knowledge Transfer group. The consultation will take into account the project's needs and wishes, as well as providing consistent advice which is aligned with the Organization's objectives towards open science and knowledge transfer.

If you do not know about the three big families of open-source licences (permissive, weakly-reciprocal and strongly-reciprocal) you can read about them in the Key concepts section. In general, when choosing a license there are a number of factors to consider, including:

  • community norms, for instance licence expectations in the Python ecosystem for a new Python package;
  • which of the three sharing regimes (permissive, weakly-reciprocal and strongly-reciprocal) is the best fit for the goal of your project. These regimes are explained in the Key concepts section.

The OSPO team is ready to help. Below you can find an overview of the considerations that the team will take into account.

Licensing software

Use a common licence approved by the Open Source Initiative (OSI) for CERN copyrighted software.

This section is currently under development by the OSPO team. Please contact the OSPO at Open.Source@cern.ch in case of questions.

Licensing hardware

At CERN, you should use one of the three variants of CERN OHL v2 for your hardware designs:

  • CERN-OHL-P-2.0 is a permissive licence (txt, pdf)
  • CERN-OHL-W-2.0 is a weakly-reciprocal licence (txt, pdf)
  • CERN-OHL-S-2.0 is a strongly-reciprocal licence (txt, pdf)

There is no particular variant which is recommended by default. You should discuss with your team and other stakeholders to see which sharing regime (P, W or S) is most appropriate in your case.

Please visit the CERN OHL v2 home to access more information about the three variants, including a rationale document explaining drafting decisions, user guides and a list of frequently asked questions.

Bear in mind that most hardware projects will come with associated software and documentation (and sometimes gateware as well) which should be licensed under appropriate open-source licences.

Licensing gateware

Permissive licences are very popular for gateware. This can be explained because:

  • The IC design industry is currently dominated by proprietary vendors and traditional reciprocal software licences have undesirable/confusing effects when applied to gateware.
  • There was up to recently no reciprocal licence drafted with gateware in mind.

One of the objectives of the authors of CERN OHL v2 was to cover gateware appropriately in all three sharing regimes. This means that you can freely choose the permissive, weakly-reciprocal or strongly-reciprocal variants of CERN OHL v2 for your HDL designs and be confident that the effects will be what you would expect from each.

There is no default recommendation for gateware developed at CERN, other than staying within the CERN OHL v2 family. You should decide on the variant taking into account any ecosystem you want to interact with and your preferences in terms of permissiveness and reciprocity.

Licensing documentation

According to CERN's Open Access Policy, the license of choice for documentation is the Creative Commons Attribution (CC-BY) license.