Licenses

Public
  - Apache
  - BSD
  - GNU General Public License (GPL)
Private
  - Proprietary

Software is controlled by copyright

Determining whether to license your project using one of the open-source licenses or whether to make your project proprietary is a difficult decision and should be taken only after the careful consideration of the consequences. Keep in mind that software is copyrighted. The software creator holds a copyright on the code, which allows the person or entity (it can be a corporation) to control how copies are made, for both source and binary forms. When the copyright holder sells a license to use the code, the copyright holder retains copyright but the licensee gains the legal right to use the code or compiled program in the manner dictated by the license.

Below, we have provided brief descriptions of the more commonly used open-source licenses. All of these open-source licenses share three central provisions:

- Free redistribution (branded distribution can be sold)
- Source code must be publicly available
- No restrictions on making and distributing modifications

We have also included the option of keeping the code proprietary, or closed source. The choice of open or closed source rests finally upon how you wish to configure project.

Public

The Apache license

The Apache license stipulates that any redistribution of the software include the text, "This product includes software developed by the Apache Software Foundation (http://www.apache.org/)." This is often called the "Acknowledgment Clause." The original BSD license had a similar clause as well, but it was removed in July of 1999. Having the clause promotes awareness of the product; removing it simplifies the act of redistribution. The Apache license also reworks the BSD's third restriction into a pair of restrictions that protect the name "Apache" from being used as the name of a derived product or to endorse the derived product.

The BSD license

Developed by the University of California, Berkeley, the BSD license is the most unrestricted of the open-source licenses. It allows for use, modification, and redistribution subject to three simple restrictions (paraphrased):

- The files must retain their original copyright and license

- Binary redistributions must include a copy of the copyright and license somewhere in the distribution

- The names of the project creators and contributors may not be used to endorse products derived from the software without permission

It also includes a standard disclaimer of warranty.

The GNU General Public License (GPL)

The GNU GPL, created by the Free Software Foundation, was the first open-source license and, in its insistence on keeping source code free, it remains the strictest. In a nutshell, the GPL stipulates not only that all "free" code must remain "free," but that all code derived in part or in whole from such code must be fall under the same license terms as the original code. On the face of it, the license would seem to encourage nonprofit development and discourage commercial interests. However, as Brian Behlendorf has argued, the GPL can provide a vehicle for the widespread establishment of a platforms that indirectly enhance commercial interests.

Proprietary

It is by no means the case that the open-source method is always the best. You can, if you wish, keep your work closed source. This means that others cannot freely work on it without your express permission.

Select references on open source

- The Open Source Initiative. An open-source advocacy group whose site houses useful links and information.
- The Open Source Software Licensing Page. A very useful site listing open-source licenses, with links to the originals and sponsoring institutions or persons.
- The Cathedral and the Bazaar. Eric Raymond's famous manifesto on open source. Required reading.
- An Introduction To Open Source Software Development. A comprehensive work by Steffen Evers describing open-source software development.

Back to main Help index