Software Licensing Guidelines
IVOA Note 2006 July 7
R. J. Hanisch
This document provides licensing guidelines for Virtual Observatory-related software developed by members of the International Virtual Observatory Alliance. Open access is encouraged to the greatest extent possible.
This is an IVOA Note expressing suggestions from and opinions of the authors. It is intended to share best practices, possible approaches, or other perspectives on interoperability with the Virtual Observatory. It should not be referenced or otherwise interpreted as a standard specification. The first release of this document was 2006-07-06.
A list of current IVOA Recommendations and other technical documents can be found at http://www.ivoa.net/Documents/.
1 Introduction 2
2 Guidelines for Software Licenses 2
Just as the IVOA promotes open access to astronomical data, the IVOA also encourages open access to astronomical software. In particular, VO Projects develop software that:
· Implements VO standard protocols and can serve as reference implementations for VO data and service providers
· Provides data discovery and visualization capabilities for VO-accessible data products
· Provides general display and plotting tools for VO-compatible data products
· Provides data analysis and integration capabilities for VO-accessible data products
· Implements or provides access to numerical simulations and sophisticated modeling algorithms
To the maximum extent possible, the IVOA promotes the free and open exchange of such software and the registration of such software in the IVOA registries or in equivalent discovery services. The IVOA encourages such software to be well-documented, including descriptions of supported platforms, operating systems, web browsers, etc.
Software developers can choose among hundreds of different software licenses, some of which are extremely open and others of which are extremely restrictive. An individual software developer may desire to release software with few or no restrictions for re-use, but can be required to use more restrictive licenses by employer policies. Developers may wish to adopt or adapt software licenses from the Open Source Initiative (OSI) at http://www.opensource.org/licenses/.
There are often legitimate reasons for restrictive licenses. For example, an organization may provide support for a widely used program or tool, and could be concerned that multiple versions having different features (or worse, inadvertent bugs) would cause user-support problems. The IVOA respects the position of such software providers.
The IVOA, therefore, makes no specific recommendation on software licenses other than to encourage the maximum openness possible, and to encourage partnership arrangements for code sharing where general open access is not possible.