licensing:MainPage

From NITRC Wiki

This wiki attempts to provide information about licensing issues. Full text of licenses (also for inclusion in distributions) can be found in the Downloads section, and additional resources can be found in the Docs section.

1 Disclaimers
2 Basics of Licensing
3 Choosing an Open Source License
- 3.1 Applying the License
4 Open Issues
5 Opinion Pieces

Disclaimers

What would a discussion on licenses be without a disclaimer?

The information found here is not legal advice; that should go without saying. But it gets worse: much of the information found here is opinion. There are conflicting, often hotly contested philosophies of licensing; we just want to give the story, not argue a point.

In addition, most of the information found here is about licensing open source code. This is because most of the experience in this community has been open source licensing. We invite people with other licensing experience to participate and contribute.

Basics of Licensing

A copyright is a set of rights granted to a creator; for a code author, this usually means exclusive rights to duplicate or modify the code. A license grants permission for others to do something with the copyrighted code; this could mean running it, modifying it, or redistributing it; these permissions may come with restrictions.

What is commonly thought of as a license is in fact the default license that the copyright holder grants; nothing prevents the copyright holder from granting a different license to specific parties.

Choosing an Open Source License

Once the choice has been made to use an open source license, it is a good idea to use a standard license (see http://www.opensource.org/licenses for a list of standard open source licenses). The advantage here is that these licenses have a lot of prior thought (often from lawyers) behind them and are well understood. Trying to roll your own invites problems.

Most of these licenses may be divided into two broad classes: GPL-like and BSD-like. GPL-like licenses allow users to modify the code and distribute the modifications, but the distribution must be similarly GPL licensed. BSD-like licenses allow users to modify the code and distribute modifications, but do not require the distribution to be open source.

The details of the licenses within these broad categories vary; it can be argued that the differences between the standard licenses listed in the above link are so subtle that the effective field of open source licenses can be reduced to a handful such as Apache 2, BSD-3-clause, FreeBSD, GPL, and LGPL or even just GPL, LGPL, and Apache 2.

Once a standard license has been selected, the temptation to add restrictions should be avoided. Many common additional disclaimers are already handled by law: "Not for clinical use" is implied in the US by anything that isn't explicitly FDA certified. Other restrictions on use such as "Not for commercial use" make the software non-free.

Remember, the standard licenses referenced above have been tested in the field. Any weaknesses in their standard form are identified and quickly corrected by people who know what they are doing (and checked by thousands others).

Applying the License

Each source file should be noted with a copyright line including the date (since copyrights do expire) and the name of the copyright holder, and a statement of the license. Full text of the license should also be included in the distribution.

The copyright holder has the power to change the default license on a software package or apply a dual license or a special case for an individual licensee.