A general introduction to free/open source software (FOSS) is provided in the first of this series of primers. That first primer is available at the International Open Source Network (IOSN) website at:
Under the prevailing copyright regime, licenses decide whether software can be free and/or open. As David A. Wheeler said, FOSS are programs whose licenses give users the freedom to run them for any purpose, to study and modify them, and to redistribute copies of either the original or modified programs without having to pay royalties to original developers. 
Starting from the mid-1980s, the birth of the GNU General Public License (GNU GPL or LGPL) has enabled a model for software development.  Following GNU GPL, various FOSS licenses have been drafted and adopted by FOSS communities, academic institutes and commercial companies. The number of FOSS licenses is growing rapidly. In early 2003, 43 licenses were recognized by the Open Source Initiative (OSI) as open source licenses. A year-and-a-half later, in July 2004, the number had reached 54. The diversity among FOSS licenses sometimes causes confusion and difficulty for people who want to participate in FOSS projects or adopt FOSS solutions. Some have argued that to reduce the transaction cost, new licenses should not be created. However, the number of FOSS licenses has been growing.
This primer aims to provide an introduction to FOSS licensing issues. It begins with a brief overview of “intellectual property” rights, and then moves on to the development of copyright law, the category of “intellectual property” that is most relevant here. The primer will then examine different proprietary and FOSS licenses which use copyright law to regulate the use of software. Finally, it briefly explains how the FOSS movement uses licenses as a way to create a different model of software development.
There are many FOSS licenses, and they may differ from each other in major ways. Due to page limitations, however, only three pervasively adopted licenses are discussed in this primer: the GNU GPL, the GNU Lesser General Public License (LGPL) and the Berkeley Software Distribution (BSD) style licenses. These three are important not only because a large number of FOSS projects are under licenses, but also because they represent very different styles of FOSS licensing.
In the last section of the primer, some scenarios are given to highlight possible copyright issues regarding the use of FOSS by end-users, developers and vendors. Given the increased attention paid by governments to FOSS development, the primer also includes two cases regarding government-sponsored FOSS projects.
- ^ Wheeler, D., "Why OSS/FS? Look at the Numbers!" Available from http://www.dwheeler.com/oss_fs_why.html; accessed on 7 November 2003.
- ^ GNU is a recursive acronym for "Gnu’s not Unix".
- ^ For example, five licenses were approved in February 2004, and two licenses were added to the list of approved licenses in June 2004. Available from http://www.opensource.org/weblog/2004/01/03#newsblog and opensource.org/weblog/2004/06/03#Jun2-04 ; accessed on 5 July 2004. As of 13 October 2006, the link is dead.
- ^ The term “Intellectual Property” covers different areas of law such as Copyright, Patent, and Trademark. Some people, especially free software advocates, advise against using the term because they believe that these different areas of law cannot be generalized. Another reason to object to its usage is that the term implies that these disparate legal issues are taken as based on an analogy of the property rights to tangible objects, whereas software is intangible. See, for example, “Some Confusing or Loaded Words and Phrases that are Worth Avoiding.” Available from http://www.gnu.org/philosophy/words-to-avoid.html ; accessed on 13 October 2006. It is true that the term “intellectual property” is relatively new and is loaded with the above meaning. Nevertheless, since the existing legal structure does take intangible objects as tangible objects, the term is still used in this primer but is within quotation marks to draw attention to these critical opinions.