Free software
'''Free software''' or software libre is [[software]] that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with minimal restrictions only to ensure that further recipients can also do these things.  In practice, for software to be distributed as free software, the human readable form of the program (the "[[source code]]") must be made available to the recipient along with a notice granting the above permissions.  Such a notice is a "[[free software licence]]", or, in theory, could be a notice saying that the source code is released into the [[public domain]].

The [[free software movement]] was conceived in 1983 by [[Richard Stallman]] to make these freedoms available to every computer user.<ref>{{ cite web | url = http://www.gnu.org/gnu/initial-announcement.html | title = GNU project Initial Announcement }}</ref> From the late 1990s onward, [[alternative terms for free software]] came into use.  "'''[[Open source software]]'''" is the most common such alternative term.  Others include "'''software [[Gratis versus Libre|libre]]'''", "free, libre and open-source software" ("'''[[FOSS]]'''", or, with "libre", "'''FLOSS'''"). The antonym of free software is "''[[proprietary software]]''" or ''non-free software''.

Free software is distinct from "[[freeware]]" which is [[proprietary software]] made available free of charge. Users usually cannot study, modify, or redistribute freeware. 

Since free software may be freely redistributed, it generally is available at little or no cost. Free software business models are usually based on adding value such as support, training, customization, integration, or certification. At the same time, some business models which work with [[proprietary software]] are not compatible with free software, such as those that depend on a user paying for a licence in order to lawfully use a software product.

== History ==
{{main|History of free software}}

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 by hardware manufacturers who were glad that people were making software that made their hardware useful. In the 1970s and early 1980s, the [[software industry]] began  using technical measures (such as only distributing [[Executable|binary copies]] of [[computer programs]]) to prevent [[computer users]] from being able to study and modify software.<ref>{{cite web
|url=http://www.dwheeler.com/oss_fs_why.html#history
|title=Appendix "History" of Why OSS/FS, Look at the Numbers!
|author=[[David A. Wheeler]]
|quote=However, as years progressed, and especially in the 1970s and 1980s, software developers increasingly closed off their software source code from users.|}}</ref>. In 1980 [[copyright]] law was extended to computer programs.

In 1983, [[Richard Stallman]], longtime member of the [[hacker (free and open source software)|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. He developed a free software definition and the concept of "[[copyleft]]", designed to ensure software freedom for all.

[[Image:Portrait - Denmark DTU 2007-3-31.jpg|thumb|Richard Stallman at DTU in Denmark 31 March 2007]]

Free software is a widespread international concept, producing software used by individuals, large organizations, and governmental administrations. Free software has a very high market penetration in server-side Internet applications such as the [[Apache web server]], [[MySQL]] database, and [[PHP]] scripting language. Completely free computing environments are available as large packages of basic system software, such as the many [[GNU/Linux distribution]]s and [[FreeBSD]]. Free software [[Software development|developers]] have also created free versions of almost all commonly used desktop applications, including Web browsers, office productivity suites, and multimedia players. It is important to note, however, that in many categories, free software for individual [[workstation]]s or home users has only a fraction of the market share of its proprietary competitors. Most free software is distributed [[online]] without charge, or [[off-line]] at the [[marginal cost]] of distribution, but this pricing model is not required, and people may sell copies of free software programs for any price.

The economic viability of free software has been recognised by large corporations such as [[IBM]], [[Red Hat]], and [[Sun Microsystems]].{{Fact|date=July 2008}} Many companies whose core business is not in the IT sector choose free software for their Internet information and sales sites, due to the lower initial capital investment and ability to freely customize the application packages. Also, some non-software industries are beginning to use techniques similar to those used in free software development for their research and development process; scientists, for example, are looking towards more open development processes, and hardware such as microchips are beginning to be developed with specifications released under [[copyleft]] licenses (see the [[OpenCores]] project, for instance). [[Creative Commons]] and the [[free culture movement]] have also been largely influenced by the free software movement.

===Naming===
The FSF recommends using the term "free software" rather than "open source software" because that term and the associated marketing campaign focuses on the technical issues of software development, avoiding the issue of user freedoms.<ref>{{ cite web | url = http://www.gnu.org/philosophy/open-source-misses-the-point.html | title = Why "Open Source" misses the point of Free Software | quote = The philosophy of open source, with its purely practical values, impedes understanding of the deeper ideas of free software; it brings many people into our community, but does not teach them to defend it. }}</ref> "[[Libre]]" is used to avoid the ambiguity of the word "free". However, amongst English speakers, ''libre'' is primarily only used within the free software movement.

== Definition ==
{{main|The Free Software Definition|Debian Free Software Guidelines|Open Source Definition}}

The first formal definition of free software was published by FSF in February 1986.<ref name=bull6>{{cite web
|url=http://www.gnu.org/bulletins/bull1.txt
|title=GNU's Bulletin, Volume 1 Number 1, page 8
|}}</ref>  That definition, written by Richard Stallman, is still maintained today and states that software is free software if people who receive a copy of the software have the following four freedoms:

* Freedom 0: The freedom to run the program for any purpose.
* Freedom 1: The freedom to study and modify the program.
* Freedom 2: The freedom to copy the program so you can help your neighbor.
* Freedom 3: The freedom to improve the program, and release your improvements to the public, so that the whole community benefits.

Freedoms 1 and 3 require [[source code]] to be available because studying and modifying software without its source code is highly impractical.

Thus, free software means that [[user (computing)|computer users]] have the freedom to cooperate with whom they choose, and to control the software they use.  To summarize this into a remark distinguishing ''[[Gratis versus Libre|libre]]'' (freedom) software from ''[[Gratis versus Libre|gratis]]'' (zero price) software, [[Richard Stallman]] said: "''Free software is a matter of liberty, not price. To understand the concept, you should think of 'free' as in '[[free speech]]', not as in '[[free beer]]<nowiki>'</nowiki>''".<ref name="definition">{{cite web|url=http://www.gnu.org/philosophy/free-sw.html |title=The Free Software Definition |author=Free Software Foundation |accessdate=2007-04-22}}</ref>  

In the late 90s, other groups published their own definitions which describe an almost identical set of software.  The most notable are [[Debian Free Software Guidelines]] published in 1997,<ref>{{cite web
|author=Bruce Perens
|url=http://lists.debian.org/debian-announce/debian-announce-1997/msg00017.html
|title=Debian's "Social Contract" with the Free Software Community
|work=debian-announce mailing list
|}}</ref> and the [[Open Source Definition]], published in 1998.

The BSD-based operating systems, such as [[FreeBSD]], [[OpenBSD]], and [[NetBSD]], do not have their own formal definitions of free software.  Users of these systems generally find the same set of software to be acceptable, but sometimes see copyleft as restrictive.  They generally advocate [[permissive free software licenses]], which allow others to make software based on their source code, and then release the modified result as proprietary software.  Their view is that this permissive approach is more free.  The [[Kerberos (protocol)|Kerberos]], [[X.org]], and [[Apache License|Apache]] software licenses are substantially similar in intent and implementation.  All of these software packages originated in academic institutions interested in wide technology transfer ([[University of California]], [[Massachusetts Institute of Technology|MIT]], and [[University of Illinois at Urbana-Champaign|UIUC]]).

== Examples of free software ==
{{main|List of open source software packages|Portal:Free software/Categories|:Category:Free software}}
The [[Free Software Directory]] is a free software project that maintains a large database of free software packages.
===Notable free software===

* [[Graphical user interface|GUI]] related
**[[X Window System]]
**[[GNOME]]
**[[KDE]]
**[[Xfce]] desktop environments
* [[OpenOffice.org]] office suite
* [[Mozilla Application Suite|Mozilla]] and [[Mozilla Firefox|Firefox]] web browsers.
* Typesetting and document preparation systems
**[[TeX]]
**[[LaTeX]]
* Graphics tools like [[GIMP]] image graphics editor and [[Blender (software)|Blender]] 3D animation program.
* [[Text editor]]s like [[vi]] or [[emacs]].
* [[ogg]] is a free software multimedia container, used to hold [[ogg vorbis]] sound and [[ogg theora]] video.
* [[Relational database]] systems
**[[MySQL]]
**[[PostgreSQL]]
* [[GNU Compiler Collection|GCC]] compilers, [[GDB]] debugger and the [[GNU C Library]].
====Programming languages====
*[[Java (programming language)|Java]]
*[[Perl]]
*[[PHP]]
*[[Python (programming language)|Python]]
*[[Lua (programming language)|Lua]]
*[[Ruby programming language|Ruby]]
*[[Tcl]]

====Servers====
*[[Apache HTTP Server|Apache web server]]
*[[BIND]] name server
*[[Sendmail]] mail transport
*[[Samba software|Samba]] file server.

====Operating systems====
*[[GNU/Linux]]
*[[Berkeley Software Distribution|BSD]]
*[[Darwin (operating system)|Darwin]]
*[[OpenSolaris]]

== Free software licenses ==
{{main|Free software licenses}}

All free software licenses must grant people all the freedoms discussed above. However, unless the applications' licenses are compatible, combining programs by mixing source code or directly linking binaries is problematic, because of license technicalities. Programs indirectly connected together may avoid this problem.

The majority of free software uses a small set of licenses. The most popular of these licenses are:

* the [[GNU General Public License]]
* the [[GNU Lesser General Public License]]
* the [[BSD License]]
* the [[Mozilla Public License]]
* the [[MIT License]]
* the [[Apache License]]

The Free Software Foundation and the Open Source Initiative both publish lists of licenses that they find to comply with their own definitions of free software and open-source software respectively.

* [[List of FSF approved software licenses]]
* [[List of OSI approved software licenses]]

These lists are necessarily incomplete, because a license need not be known by either organization in order to provide these freedoms.

Apart from these two organizations, the [[Debian]] project is seen by some to provide useful advice on whether particular licenses comply with their [[Debian Free Software Guidelines]].  Debian doesn't publish a list of ''approved'' licenses, so its judgments have to be tracked by checking what software they have allowed into their software archives. That is summarized at the Debian web site.<ref>{{cite web |url=http://www.debian.org/legal/licenses/ |title=Debian -- License information |accessdate=2008-01-08}}</ref>

However, it is rare that a license is announced as being in-compliance by either FSF or OSI guidelines and not [[Vice_versa##vice_versa|vice versa]] (the [[Netscape Public License]] used for early versions of Mozilla being an exception), so exact definitions of the terms have not become hot issues.

=== Permissive and copyleft licenses ===

The FSF categorizes licenses in the following ways:

* [[Public domain]] software - the copyright has expired, the work was not copyrighted or the author has abandoned the copyright. Since public-domain software lacks copyright protection, it may be freely incorporated into any work, whether proprietary or free. 
* [[permissive free software licences|Permissive licenses]], also called BSD-style because they are applied to much of the software distributed with the [[Berkeley Software Distribution|BSD]] operating systems. The author retains copyright solely to disclaim warranty and require proper attribution of modified works, but permits redistribution and modification in ''any'' work, even proprietary ones.
* [[Copyleft]] licenses, the [[GNU General Public License]] being the most prominent. The author retains copyright and permits redistribution and modification provided all such redistribution is licensed under the same license. Additions and modifications by others must also be licensed under the same 'copyleft' license whenever they are distributed with part of the original licensed product.

== Security and reliability==

There is debate over the [[computer security|security]] of free software in comparison to proprietary software, with a major issue being [[security through obscurity]]. A popular quantitative test in computer security is using relative counting of known unpatched security flaws. Generally, users of this method advise avoiding products which lack fixes for known security flaws, at least until a fix is available. Some claim that this method is biased by counting more vulnerabilities for the free software, since its source code is accessible and its community is more forthcoming about what problems exist.<ref>{{ cite web | url = http://news.com.com/8301-10784_3-6047727-7.html | title = Firefox more secure than MSIE after all | publisher = News.com }}</ref>

Free software advocates rebut that even if proprietary software does not have "published" flaws, flaws could still exist and possibly be known to malicious users. The ability of users to view and modify the source code allows many more people to potentially analyse the code and possibly to have a higher rate of finding bugs and flaws than an average sized corporation could manage. Users having access to the source code also makes creating and deploying [[spyware]] far more difficult.<ref>{{cite web|url=http://fsfeurope.org/documents/rms-fs-2006-03-09.en.html#freedom-one|title=Transcript where Stallman explains about spyware|}}</ref>

[[David A. Wheeler]] has published research concluding that free software is quantitatively more reliable than proprietary software.<ref>{{cite web
|url=http://www.dwheeler.com/essays/high-assurance-floss.html
|title=High Assurance (for Security or Safety) and Free-Libre / Open Source Software (FLOSS)... with Lots on Formal Methods
|author=David A. Wheeler}}</ref>

== Adoption ==

Free software played a part in the development of the Internet, the World Wide Web and the infrastructure of [[dot-com companies]].<ref name="Web Server Survey">{{cite web|url=http://news.netcraft.com/archives/web_server_survey.html |title=Web Server Usage Survey |author=Netcraft}}</ref>
<ref name="Apache Strategy">{{cite web|url=http://www.unc.edu/~mohrmana/apache.pdf |title=Apache Strategy in the New Economy |author=The Apache Software Foundation}}</ref> Free software allows users to cooperate in enhancing and refining the programs they use; free software is a [[pure public good]] rather than a [[private good]]. Companies that contribute to free software can increase commercial [[innovation]] amidst the void of [[patent]] [[cross licensing]] lawsuits. (See [[Mpeg2#Patent holders|mpeg2 patent holders]])

Under the free software business model, free software vendors may charge a fee for distribution and offer pay support and software customization services. Proprietary software uses a different business model, where a customer of the proprietary software pays a fee for a license to use the software. This license may grant the customer the ability to configure some or no parts of the software themselves. Often some level of support is included in the purchase of proprietary software, but additional support services (especially for enterprise applications) are usually available for an additional fee. Some proprietary software vendors will also customize software for a fee.

Free software is generally available at little to no cost and can result in permanently lower costs compared to [[proprietary software]]. With free software, businesses can fit software to their specific needs by changing the software themselves or by hiring programmers to modify it for them.  Free software often has no warranty, and more importantly, generally does not assign legal liability to anyone. However, warranties are permitted between any two parties upon the condition of the software and its usage. Such an agreement is made separately from the free software license.

== Controversies ==
=== Binary blobs ===
{{main|Binary blobs}}
In 2006, [[OpenBSD]] started the first campaign against the use of [[binary blobs]], in [[kernel (computer science)|kernels]]. Blobs are usually freely distributable [[device driver]]s for hardware from vendors that do not reveal driver source code to users or developers. This restricts the users' freedom to effectively modify the software and distribute modified versions. Also, since the blobs are undocumented and may have [[computer bug|bugs]], they pose a security risk to any [[operating system]] whose kernel includes them. The proclaimed aim of the campaign against blobs is to collect hardware documentation that allows developers to write free software drivers for that hardware, ultimately enabling all free operating systems to become or remain blob-free.

The issue of binary blobs in the [[Linux kernel]] and other device drivers motivated some developers in Ireland to launch [[gNewSense]], a GNU/Linux distribution with all the binary blobs removed.  The project received support from the [[Free Software Foundation]]<ref>[http://www.gnu.org/links/links.html#FreeGNULinuxDistributions GNU/Linux distributions we know of which consist entirely of free software, and whose main distribution sites distribute only free software.]</ref>

=== BitKeeper ===
{{main|BitKeeper#License concerns}}

[[Larry McVoy]] invited high-profile free software projects to use his proprietary [[versioning system]], [[BitKeeper]], free of charge, in order to attract paying users. In 2002, Linux coordinator [[Linus Torvalds]] decided to use BitKeeper to develop the Linux kernel, a free software project, claiming no free software alternative met his needs. This controversial decision drew criticism from several sources, including the Free Software Foundation's founder Richard Stallman.<ref>{{cite web | title = Richard Stallman thanking Larry McVoy for ending the gratis licenses for BitKeeper | url = http://software.newsforge.com/article.pl?sid=05/04/25/130207 | publisher = [[NewsForge]] }}</ref>

Following the apparent [[reverse engineering]] of BitKeeper's protocols, McVoy withdrew permission for gratis use by free software projects, leading the Linux kernel community to develop a free software replacement in [[Git (software)|Git]].

=== Patent deals ===
{{main|Software patents and free software}}

In November 2006, the [[Microsoft]] and [[Novell]] software corporations announced a controversial partnership involving, among other things, patent protection for some customers of Novell under certain conditions.<ref>{{ cite web | title = Ars Technica article on the Microsoft-Novell patent deal | url = http://arstechnica.com/articles/columns/linux/linux-20070128.ars }}</ref>

== See also ==
{{portal|Free software|Free Software Portal Logo.svg}}
* [[Free content]]
* [[Free software community]]
* [[Free file format]]
* [[Free software licenses]]
* [[Gratis versus Libre]]
* [[List of free software packages]]
* [[List of free software project directories]]
* [[List of formerly proprietary software]]
* [[Libre knowledge]]

== References ==
{{reflist|2}}

== External links ==
{{wikinewscat|FLOSS}}
* [http://www.gnu.org/philosophy/free-sw.html The Free Software Definition]
* [http://fsfe.org/transcripts Transcripts about Free Software] by [[FSFE]]
* [http://www.freesoftwaremagazine.com Free Software Magazine]
* [http://freedomdefined.org/Definition Free cultural works definition]
* [http://www.dwheeler.com/oss_fs_why.html Why Open Source Software / Free Software (OSS/FS)? Look at the Numbers!], analysis of the advantages of OSS/FS by [[David A. Wheeler]].
* [http://www.flossworld.org/index.php FLOSSWorld - Free/Libre/Open-Source Software: Worldwide impact study]
* [http://www.teak.cc/softfree/software-freedom.html Software Freedom: An Introduction], by [[Robert J. Chassell]]
* [http://www.sci.brooklyn.cuny.edu/~bcfoss/DL Decoding Liberation: The Promise of Free and Open Source Software], by Samir Chopra and Scott Dexter
* [http://www.linfo.org/free_software.html Free Software Definition at The Linux Information Project]
* [http://sourceforge.net/ Sourceforge.net] 

{{software distribution}}
{{FOSS}}

[[Category:Free software| ]]
[[Category:Software licenses]]
[[Category:Libre]]
[[Category:Digital Revolution]]
[[Category:Free software culture and documents]]

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