Version 3 (modified by jkantor, 11 years ago) (diff)



LSST as a project has a mandate to publish all of its software as open source. There are a multitude of open source/free software licenses to choose from. At the same time, LSST has a few specific desiderata to take into consideration when choosing the "right" license:

  • Acknowledgement and credit of authorship
  • Establishing ownership without restricting use
  • Preserving all non-commercial use
  • Allowing, but not necessarily encouraging, commercial use

Another issue to take into consideration is that of copyright. Code written using LSST funds would have the approved LSST copyright notice, all other code would have the appropriate copyright notice instead. Whatever license is chosen should allow the specification and preservation of different copyright notices.


Given all the above, the Apache License 2.0 appears to be a good fit. It allows users of Apache licensed software to

  • Copy, distribute and modify the software
  • Exercise patent rights on the portions of software that they use that would normally only be the right of the licensor only

At the same time, the Apache license requires that

  • All copies, modified or unmodified, are accompanied by a copy of the license
  • All modifications are clearly marked as being the work of the modifier
  • All notices of copyright, trademark and patent rights are reproduced accurately in distributed copies
  • The licensee does not start legal action against the licensor(s) over patent infringement
  • The licensee does not use any trademarks that belong to the licensor

It is useful to note that software distributed under the Apache license 2.0 is provided as is (i.e. without any warranty of any sort).

Further Resources

  1. OSS Watch discussion of the Apache License 2.0
  2. Wikipedia Article on Apache License 2.0