Open source software (OSS) began as a marketing campaign for free software. OSS can be defined as computer software for which the human-readable source code is made available under a copyright license (or arrangement such as the public domain) that meets the Open Source Definition. This permits users to use, change, and improve the software, and to redistribute it in modified or unmodified form. It is very often developed in a public, collaborative manner. Open source software is the most prominent example of open source development and often compared to user generated content. A report by Standish Group says that adoption of open source has caused a drop in revenue to the proprietary software industry by about $60 billion per year.

Open Source Definition

The Open Source Definition is used by the Open Source Initiative to determine whether or not a software license can be considered open source.

The definition was based on the Debian Free Software Guidelines, written and adapted primarily by Bruce Perens.

History

main: Open source movement

The free software movement was launched in 1983. In 1998, a group of individuals advocated that the term free software be replaced by open source software (OSS) as an expression which is less ambiguous and more comfortable for the corporate world. Software developers may want to publish their software with an open source license, so that anybody may also develop the same software or understand how it works. Open source software generally allows anyone to make a new version of the software, port it to new operating systems and processor architectures, share it with others or market it. The aim of open source is to let the product be more understandable, modifiable, duplicatable,reliable or simply accessible, while it is still marketable.

The Open Source Definition, notably, presents an open source philosophy, and further defines a boundary on the usage, modification and redistribution of open source software. Software licenses grant rights to users which would otherwise be prohibited by copyright. These include rights on usage, modification and redistribution. Several open source software licenses have qualified within the boundary of the Open Source Definition. The most prominent example is the popular GNU General Public License (GPL). While open source presents a way to broadly make the sources of a product publicly accessible, the open source licenses allow the authors to fine tune such access.

The "open source" label came out of a strategy session held in Palo Alto in reaction to Netscape's January 1998 announcement of a source code release for Navigator (as Mozilla). A group of individuals at the session included Todd Anderson, Larry Augustin, John Hall, Sam Ockman, Christine Peterson and Eric S. Raymond. They used the opportunity before the release of Navigator's source code to clarify a potential confusion caused by the ambiguity of the word "free" in English. The 'open source' movement is generally thought to have begun with this strategy session. Many people, nevertheless, claimed that the birth of the Internet, since 1969, started the open source movement, while others do not distinguish between open source and free software movements.