Free and open-source software (F/OSS, FOSS) or free/libre/open-source software (FLOSS) is software that is liberally licensed to grant users the right to use, copy, study, change, and improve its design through the availability of its source code. This approach has gained both momentum and acceptance as the potential benefits have been increasingly recognized by both individuals and corporations.
In the context of free and open-source software, free refers to the freedom to copy and re-use the software, rather than to the price of the software. The Free Software Foundation, an organization that advocates the free software model, suggests that, to understand the concept, one should "think of free as in free speech, not as in free beer".
FOSS is an inclusive term that covers both free software and open source software, which despite describing similar development models, have differing cultures and philosophies. Free software focuses on the philosophical freedoms it gives to users, whereas open source software focuses on the perceived strengths of its peer-to-peer development model. FOSS is a term that can be used without particular bias towards either political approach.
Software which is both gratis and free software may be called gratis/libre/open-source software (GLOSS).
Free software licences and open source licenses are used by many software packages. While the licenses themselves are in most cases the same, the two terms grew out of different philosophies and are often used to signify different distribution methodologies.
In the 1950s, 1960s, and 1970s, it was normal for computer users to have the freedoms that are provided by free software. Software was commonly shared by individuals who used computers and most companies were so concerned with selling their hardware devices, they provided the software for free. Organizations of users and suppliers were formed to facilitate the exchange of software; see, for example, SHARE and DECUS. By the late 1960s change was inevitable: software costs were dramatically increasing, a growing software industry was competing with the hardware manufacturer's bundled software products (free in that the cost was included in the hardware cost), leased machines required software support while providing no revenue for software, and some customers able to better meet their own needs did not want the costs of "free" software bundled with hardware product costs. In United States vs. IBM, filed January 17, 1969, the government charged that bundled software was anticompetitive. While some software might always be free, there would be a growing amount of software that was for sale only. In the 1970s and early 1980s, the software industry began using technical measures (such as only distributing binary copies of computer programs) to prevent computer users from being able to study and customize software they had bought using reverse engineering techniques. In 1980 the copyright law (Pub. L. No. 96-517, 94 Stat. 3015, 3028) was extended to computer programs in the United States
In 1983, Richard Stallman, longtime member of the hacker community at the MIT Artificial Intelligence Laboratory, announced the GNU project, saying that he had become frustrated with the effects of the change in culture of the computer industry and its users. Software development for the GNU operating system began in January 1984, and the Free Software Foundation (FSF) was founded in October 1985. An article outlining the project and its goals was published in March 1985 titled the GNU Manifesto. The manifesto also focused heavily on the philosophy of free software. He developed The Free Software Definition and the concept of "copyleft", designed to ensure software freedom for all.
The Linux kernel, started by Linus Torvalds, was released as freely modifiable source code in 1991. The licence wasn't exactly a free software licence, but with version 0.12 in February 1992, he relicensed the project under the GNU General Public License. Much like Unix, Torvalds' kernel attracted the attention of volunteer programmers.
In 1997, Eric Raymond published The Cathedral and the Bazaar, a reflective analysis of the hacker community and free software principles. The paper received significant attention in early 1998, and was one factor in motivating Netscape Communications Corporation to release their popular Netscape Communicator Internet suite as free software. This code is today better known as Mozilla Firefox and Thunderbird.
Netscape's act prompted Raymond and others to look into how to bring free software principles and benefits to the commercial software industry. They concluded that FSF's social activism was not appealing to companies like Netscape, and looked for a way to rebrand the free software movement to emphasize the business potential of the sharing of source code. The new name they chose was "open source", and quickly Bruce Perens, publisher Tim O'Reilly, Linus Torvalds, and others signed on to the rebranding. The Open Source Initiative was founded in February 1998 to encourage use of the new term and evangelize open source principles.
While the Open Source Initiative sought to encourage the use of the new term and evangelize the principles it adhered to, corporations found themselves increasingly threatened by the concept of freely distributed software and universal access to an application's source code. A Microsoft executive publicly stated in 2001 that "open source is an intellectual property destroyer. I can't imagine something that could be worse than this for the software business and the intellectual-property business."  This view perfectly summarizes the initial response to FOSS by the majority of big business. However, while FOSS has historically played a role outside of the mainstream of private software development, companies as large as Microsoft have begun to develop official open source presences on the Internet. Corporations ranging from IBM, Oracle, Google and State Farm are just a few of the big names with a serious public stake in today's competitive open source market signalling a shift in the corporate philosophy concerning the development of free to access software.
The Free Software Definition, written by Richard Stallman and published by Free Software Foundation (FSF), defines free software as a matter of liberty, not price. The earliest known publication of the definition was in the February 1986 edition of the now-discontinued GNU's Bulletin publication of FSF. The canonical source for the document is in the philosophy section of the GNU Project website. As of April 2008, it is published there in 39 languages.
The Open Source Definition is used by the Open Source Initiative to determine whether 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. Perens did not base his writing on the four freedoms of free software from the Free Software Foundation, which were only later available on the web.
The first known use of the phrase free open source software on Usenet was in a posting on 18 March 1998, just a month after the term open source itself was coined. In February 2002, F/OSS appeared on a Usenet newsgroup dedicated to Amiga computer games. In early 2002, MITRE used the term FOSS in what would later be their 2003 report Use of Free and Open Source Software (FOSS) in the U.S. Department of Defense.
The acronym FLOSS was coined in 2001 by Rishab Aiyer Ghosh for free/libre/open source software. Later that year, the European Commission (EC) used the phrase when they funded a study on the topic.
Unlike libre software, which aimed to solve the ambiguity problem, FLOSS aimed to avoid taking sides in the debate over whether it was better to say "free software" or to say "open source software".
Proponents of the term point out that parts of the FLOSS acronym can be translated into other languages, with for example the F representing free (English) or frei (German), and the L representing libre (Spanish or French), livre (Portuguese), or libero (Italian), liber (Romanian) and so on. However, this term is not often used in official, non-English, documents, since the words in these languages for free as in freedom do not have the ambiguity problem of free in English.
The terms "FLOSS" and "FOSS" have come under some criticism for being counterproductive and sounding silly. For instance, Eric Raymond, co-founder of the Open Source Initiative, has stated:
"Near as I can figure ... people think they’d be making an ideological commitment ... if they pick 'open source' or 'free software'. Well, speaking as the guy who promulgated 'open source' to abolish the colossal marketing blunders that were associated with the term 'free software', I think 'free software' is less bad than 'FLOSS'. Somebody, please, shoot this pitiful acronym through the head and put it out of our misery."
Raymond quotes programmer Rick Moen as stating
"I continue to find it difficult to take seriously anyone who adopts an excruciatingly bad, haplessly obscure acronym associated with dental hygiene aids" and "neither term can be understood without first understanding both free software and open source, as prerequisite study."
Dualism of FOSSEdit
While the Open Source Initiative includes free software licenses as part of its broader category of approved open source licenses, the Free Software Foundation sees free software as distinct from open source. The key differences between the two are their approach to copyright and appropriation in the context of usage.
The primary obligation of users of traditional open source licenses such as BSD is limited to appropriation that clearly identifies the copyright owner of the software. Such a license is focused on providing developers who wish to redistribute the software the greatest level flexibility. Users who do not wish to redistribute the software in any form are under no obligation. Developers can modify the software and redistribute it either as source or as part of a larger, possibly proprietary, derived work, provided the original appropriation is intact. These appropriations throughout the distribution chain ensure the owners' copyrights are maintained.
The primary obligation of users of free software licenses such as the GPL is to preserve the rights of other users under the terms of the license. Such a license is focused on ensuring that users' rights to access and modify the software cannot be denied by developers who redistribute the software. The only way to accomplish this is by restricting the rights of developers to include free software in larger, derived works unless those works share the same free software license. Free software uses copyright to enforce compliance with the software license. To strengthen its legal position, the Free Software Foundation asks developers to assign copyright to the Foundation when using the GPL license.
From a user's (non-distributor's) perspective, both free software and open source can be treated as effectively the same thing and referred to with the inclusive term FOSS. From a developer's (distributor's) perspective, free and open source software are distinct concepts with much different legal implications.
While copyright is the primary legal mechanism that FOSS authors use to control usage and distribution of their software, other mechanisms such as legislation, patents, and trademarks have implications as well. In response to legal issues with patents and the DMCA, the Free Software Foundation released version 3 of its GNU Public License in 2007 that explicitly addressed the DMCA and patent rights.
As author of the GCC compiler software, the FSF also exercised its copyright and changed the GCC license to GPLv3. As a user of GCC, and a heavy user of both DRM and patents, it is speculated that this change caused Apple, Inc. to switch the compiler in its Xcode IDE from GCC to the open source Clang compiler. The Samba project also switched to the GPLv3 in a recent version of its free Windows-compatible network software. In this case, Apple replaced Samba with closed-source, proprietary software - a net loss for the FOSS movement as a whole.
Some of the most popular FOSS projects are owned by corporations that, unlike the FSF, use both patents and trademarks to enforce their rights. In August, 2010, Oracle sued Google claiming that its use of the open source Java infringed on Oracle's patents. Oracle acquired those patents with its acquisition of Sun Microsystems in January, 2010. Sun had, itself, acquired MySQL in 2008. This made Oracle the owner of the most popular proprietary database and the most popular open source database. Oracle's attempts to commercialize the open source MySQL database have raised concerns in the FOSS community. In response to uncertainty about the future of MySQL, the FOSS community used MySQL's GPL license to fork the project into a new database outside of Oracle's control. This new database, however, will never be MySQL because Oracle owns the trademark for that term.
Future economics of FOSSEdit
According to Yochai Benkler, Jack N. and Lillian R. Berkman Professor for Entrepreneurial Legal Studies at Harvard Law School, free software is the most visible part of a new economy of commons-based peer production of information, knowledge, and culture. As examples, he cites a variety of FOSS projects, including both free software and open source.
This new economy is already under development. In order to commercialize FOSS, many companies, Google being the most successful, are moving towards an economic model of advertising-supported software. In such a model, the only way to increase revenue is to make the advertising more valuable. Facebook has recently come under fire for using novel user tracking methods to accomplish this.
Adoption by governmentsEdit
The Government of Kerala, India, announced its official support for Free/Open Source Software in its State IT Policy of 2001, which was formulated after the first-ever Free Software Conference in India, "Freedom First!", held in July 2001 in Trivandrum, the capital of Kerala..
The German City of Munich announced its intention to switch from Microsoft Windows-based operating systems to an open source implementation of SuSE Linux in March 2003, having achieved an adoption rate of 20% by 2010.
In 2004, a law in Venezuela (Decree 3390) went into effect, mandating a two year transition to open source in all public agencies. As of June 2009 this ambitious transition is still under way. Malaysia launched the "Malaysian Public Sector Open Source Software Program", saving millions on proprietary software licences till 2008.
In 2005 the Government of Peru voted to adopt open source across all its bodies. The 2002 response to Microsoft's critique is available online. In the preamble to the bill, the Peruvian government stressed that the choice was made to ensure that key pillars of democracy were safeguarded: "The basic principles which inspire the Bill are linked to the basic guarantees of a state of law." In September, the Commonwealth of Massachusetts announced its formal adoption of the OpenDocument standard for all Commonwealth entities.
In 2006, the Brazilian government has simultaneously encouraged the distribution of cheap computers running Linux throughout its poorer communities by subsidizing their purchase with tax breaks.
In April, Ecuador passed a similar law, Decree 1014, designed to migrate the public sector to Software Libre.
In February 2009, the United States White House moved its website to Linux servers using Drupal for content management. In March, the French Gendarmerie Nationale announced it will totally switch to Ubuntu by 2015.
In January 2010, the Government of Jordan announced that it has formed a partnership with Ingres Corporation, a leading open source database management company based in the United States that is now known as Actian Corporation, to promote the use of open source software starting with university systems in Jordan. 
- Hatlestad, Luc (2005-08-09). "LinuxWorld Showcases Open-Source Growth, Expansion". InformationWeek. CMP Media, LLC. Archived from the original on 2007-11-25. http://www.webcitation.org/5Tchd69ij. Retrieved 2007-11-25.
- Claburn, Thomas (January 17, 2007). "Study Finds Open Source Benefits Business". InformationWeek. CMP Media LLC. Archived from the original on 2007-11-25. http://www.webcitation.org/5TchF5fkl. Retrieved 11 2 5 2007.
- "The Free Software Definition". GNU.org. http://www.gnu.org/philosophy/free-sw.html. Retrieved 2010-02-04.
- Feller (2005), p. 89, 362
- Feller (2005), pp. 101–106, 110–111.
- Barr, Joe (1998). "Why "Free Software" is better than "Open Source"". Free Software Foundation. Archived from the original on 2007-11-25. http://www.webcitation.org/5TchyyzYm. Retrieved 2007-11-25.
- Free and Open Source Software, IEEE Computer Society
- Fisher, Franklin M.; McKie, James W.; Mancke, Richard B. (1983). IBM and the U.S. Data Processing Industry: An Economic History. Praeger. ISBN 0-03-063059-2.
- Computer Software 1980 Copyright Act, Pub. L. No. 96-517, 94 Stat. 3015, 3028.
- William 2002
- "Release notes for Linux kernel 0.12". Kernel.org. http://www.kernel.org/pub/linux/kernel/Historic/old-versions/RELNOTES-0.12.
- "History of the OSI". Opensource.org. http://opensource.org/history.
- B. Charny, “Microsof t Raps Open-Source Approach,” CNET News, 3 May 2001; http://news.cnet.com/2100-1001-257001.html&tag=mncol%3btxt
- Jeffrey Voas, Keith W. Miller & Tom Costello. Free and Open Source Software. IT Professional 12(6) (November 2010), pg. 14-16.
- "GNU.org". GNU.org. 2011-09-20. http://www.gnu.org/philosophy/free-sw.html. Retrieved 2011-10-23.
- "GNU's Bulletin, Volume 1 Number 1, page 8". GNU.org. http://www.gnu.org/bulletins/bull1.txt.
- "The Free Software Definition – Translations of this page". GNU.org. http://www.gnu.org/philosophy/free-sw.html#translations.
- "The Open Source Definition by Bruce Perens". http://www.oreilly.com/catalog/opensources/book/perens.html. , Open Sources: Voices from the Open Source Revolution, January 1999, ISBN 1-56592-582-3
- "The Open Source Definition". http://opensource.org/docs/osd. , The Open Source Definition according to the Open Source Initiative
- "Slashdot.org". News.slashdot.org. 2009-02-16. http://news.slashdot.org/comments.pl?sid=1129863&cid=26875815. Retrieved 2011-10-23.
- "Posting re "free open source software", 18 March 1998.". http://groups.google.com/groups/search?hl=en&lr=&safe=off&num=10&q=%22free+open+source+software%22&safe=off&qt_s=Search&as_drrb=b&as_mind=1&as_minm=1&as_miny=1981&as_maxd=1&as_maxm=6&as_maxy=1998.
- "Using m$ products is supporting them :(". http://groups.google.com/group/comp.sys.amiga.games/msg/4a192ea899e10c55.
- "Free/Libre and Open Source Software: Survey and Study". http://flossproject.org/.
- "Free/Libre and Open Source Software and Open Standards in South Africa: A Critical Issue for Addressing the Digital Divide". National Advisory Council on Innovation. http://www.naci.org.za/floss/index.html.
- "FLOSS deployment in Extremadura, Spain". http://ec.europa.eu/idabc/en/document/1637/470.
- "Relatório da ONU aponta o Software Livre (FLOSS) como melhor". http://www.softwarelivre.org/news/1727.
- Please forget to FLOSS Armed and Dangerous, March 26 2009
- "Licenses by Name". Open Source License. Open Source Initiative. http://www.opensource.org/licenses/alphabetical. Retrieved 23 October 2011.
- Stallman, Richard. "Why Open Source misses the point of Free Software". Free Software Foundation. http://www.gnu.org/philosophy/open-source-misses-the-point.html. Retrieved 23 October 2011.
- "Frequently Asked Questions about the GNU Licenses". Free Software Foundation. http://www.gnu.org/licenses/gpl-faq.html#AssignCopyright. Retrieved 23 October 2011.
- Vetter, Greg (1). "Commercial Free and Open Source Software: Knowledge Production, Hybrid Appropriability, and Patents". Fordham Law Review 77 (5): 2087–2141. http://ir.lawnet.fordham.edu/flr/vol77/iss5/4. Retrieved 23 October 2011.
- Brockmeier, Joe. "Apple's Selective Contributions to GCC". http://lwn.net/Articles/405417/. Retrieved 23 October 2011.
- Holwerda, Thom. "Apple Ditches SAMBA in Favour of Homegrown Replacement". http://www.osnews.com/story/24572/. Retrieved 23 October 2011.
- Thomson, Iain. "Oracle offers commercial extensions to MySQL". http://www.theregister.co.uk/2011/09/16/oracle_commercial_extensions_mysql/. Retrieved 23 October 2011.
- Samson, Ted. "Non-Oracle MySQL fork deemed ready for prime time". http://www.infoworld.com/d/open-source-software/non-oracle-mysql-fork-deemed-ready-prime-time-853. Retrieved 23 October 2011.
- Nelson, Russell. "Open Source, MySQL, and trademarks". http://www.opensource.org/node/496. Retrieved 23 October 2011.
- Benkler, Yochai (April 2003). "Freedom in the Commons: Towards a Political Economy of Information". Duke Law Journal 52 (6). http://www.law.duke.edu/shell/cite.pl?52+Duke+L.+J.+1245+pdf.
- Dina ElBoghdady; Hayley Tsukayama. "Facebook tracking prompts calls for FTC investigation". Washington Post. http://www.washingtonpost.com/business/economy/facebook-tracking-prompts-calls-for-ftc-investigation/2011/09/29/gIQAVdsP8K_story.html. Retrieved 23 October 2011.
- Vaughan-Nichols, Steven. "No GPL Apps for Apple's App Store". http://www.zdnet.com/blog/open-source/no-gpl-apps-for-apples-app-store/8046. Retrieved 23 October 2011.
- "Changing the VLC engine license to LGPL". http://www.videolan.org/press/lgpl.html. Retrieved 23 October 2011.
- "Role of Open or Free Software", Section 15, page 20, of the State IT Policy (2001) of the Government of Kerala, copy available at the UN Public Administration Network (UNPAN) site; http://unpan1.un.org/intradoc/groups/public/documents/apcity/unpan002950.pdf
- Casson, Tony; Ryan, Patrick S. (May 1, 2006). "Open Standards, Open Source Adoption in the Public Sector, and Their Relationship to Microsoft’s Market Dominance". in Bolin, Sherrie. Standards Edge: Unifier or Divider?. Sheridan Books. p. 87. http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1656616.
- "Declaration of Independence: The LiMux Project in Munich". Osor.eu. http://www.osor.eu/case_studies/declaration-of-independence-the-limux-project-in-munich. Retrieved 2011-10-23.
- "Official LiMux page". Muenchen.de. http://www.muenchen.de/Rathaus/dir/limux/english/147197/index.html. Retrieved 2011-10-23.
- (Spanish) Venezuela Open Source
- Chavez, Hugo F. (December 2004). "Publicado en la Gaceta oficial No 38.095 de fecha 28/ 12/ 2004". http://www.tsj.gov.ve/gaceta/Diciembre/281204/281204-38095-08.html. Retrieved 2011-10-23.
- "OSCC.org". OSCC.org. http://www.oscc.org.my/. Retrieved 2011-10-23.
- "OSCC.org". http://knowledge.oscc.org.my/newsletters/first-quarterly-e-newsletter-jan-2009. Retrieved 2011-10-23.
- Clarke, Gavin (2005-09-29). "TheRegister.co.uk". TheRegister.co.uk. http://www.theregister.co.uk/2005/09/29/peru_goes_open_source/. Retrieved 2011-10-23.
- National Advisory Council on Innovation Open Software Working Group (July 2004). "Free/Libre & Open Source Software and Open Standards in South Africa" (PDF). http://www.naci.org.za/pdfs/floss_v2_6_9.pdf. Retrieved 2008-05-31. [dead link]
- (Spanish) Estebanmendieta.com, Decree 1014
- Vaughan-Nichols, Steven J. "Obama Invites Open Source into the White House" in PCWorld, October 29, 2009.
- "Ars Technica – French police: we saved millions of euros by adopting Ubuntu". http://arstechnica.com/open-source/news/2009/03/french-police-saves-millions-of-euros-by-adopting-ubuntu.ars.
- "Partnership between the Government of Jordan and Ingres Corporation". http://www.software-distribution.com/news-nouvelles/news-nouvelles-recentes/12012010-government-of-jordan-selects-ingres-to-drive-opensource-adoption-across-the-country/.
- Byrne, E. J. (1991). Software reverse engineering: A case study. Software: Practice and Experience, 21(12), 1349–1364
- Feller, J., Fitzgerald, B., Hissam, S. A., Lakahani, K. R. (2005). Perspectives on Free and Open Source Software. MIT Press.
- Miller, K. W., Voas, J., & Costello, T. (2010). Free and open source software. IT Professional, 12(6), 14-16. doi:10.1109/MITP.2010.147
- Salus, P. H. (2005). A History of Free and Open Source. Retrieved from http://www.groklaw.net/article.php?story=20050327184603969.
- Vetter, G. (2009). Commercial Free and Open Source Software: Knowledge Production, Hybrid Appropriability, and Patents. Fordham Law Review, (77)5, 2087-2141..
- Wheeler, D. (2007). Why Open Source Software / Free Software (OSS/FS, FLOSS, or FOSS)? Look at the Numbers!. Retrieved from http://www.dwheeler.com/oss_fs_why.html.
- William, S. (2002). Free as in Freedom: Richard Stallman's Crusade for Free Software. O'Reilly Media.
- FOSSBazaar – community for free and open source software governance
- FLOSSworld – Free/Libre/Open Source Software: Worldwide impact study
- Free / Open Source Research Community (mit.edu)
- FreeOpenSourceSoftware.org – Wiki on FOSS history, organizations, licenses, people, software.
- International Free and Open Source Software Foundation