Free software

Free software 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 restrictions only to ensure that further recipients can also do these things. To make these acts possible, the human readable form of the program (called the source code) must be made available. The source code may be either accompanied by a software license saying that the copyright holder permits these acts (a free software licence), or be released into public domain, so that these rights automatically hold.

For political and ambiguity reasons, alternative terms for free software have been proposed. The most popular of this is "open-source software", and others include "software libre", "free, libre and open-source software" ("FLOSS"), and "free and open-source software" ("FOSS"). The antonym of free software is "proprietary software".

Free software is distinct from "freeware" which is proprietary software made available free of charge. Users usually cannot study, modify, or redistribute freeware. The only permission freeware has in common with free software is the permission to use the software.

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 having no choice but to pay for a licence in order to lawfully use a software product.

The free software movement was launched in 1983 to make these freedoms available to every computer user.^[1] Software that does not provide these freedoms is referred to as proprietary software or non-free software.

In the 50s, 60s, and 70s, it was normal for computer users to have the freedoms 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 70s and early 80s, the software industry began to apply copyright law, and began using technical measures such as only distributing binary copies, to prevent computer users from being able to study and modify the software.^[2]

In 1983, Richard Stallman launched the GNU project after becoming frustrated with the effects of the change in culture of the computer industry and users. Software development for the GNU operating system began in January 1984, and the Free Software Foundation (FSF) was founded in October 1985. He introduced a free software definition and "copyleft", designed to ensure software freedom for all.

Free software is a huge international effort, 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 Linux distributions and FreeBSD. Free software developers have also created free versions of almost all commonly used desktop applications such as web browsers, office productivity suites, and multimedia players. It is important to note, however, that in many categories, free software for individual workstation or home users has only a fraction of the market share of their proprietary competitors. Most free software is distributed online without charge, or off-line at the marginal cost of distribution, but this is not required, and people may sell copies for any price.

The economic viability of free software has been recognised by large corporations such as IBM, Red Hat, and Sun Microsystems. 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: 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" and never "open source software" because that term and the associated marketing campaign focuses on technical issues and avoids talking about the value of freedom.^[3] "Libre" is used to avoid the ambiguity of the word "free". However, libre is mostly used within the free software movement.

Definition

The first formal definition of free software was published by FSF in February 1986.^[4] 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 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 libre (freedom) software from gratis (zero price) software, Richard Stallman has long 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'".^[5]

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,^[6] 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 but users of these systems generally find the same set of software to be acceptable. However, rather than advocate the use of copyleft free software licenses, they see copyleft as being merely tolerable. Instead, they advocate permissive free software licenses which allow others to make software based on their source code and then not, in turn, also distribute the source. Their view is that this permissive approach is more free. The Kerberos, X.org, and Apache software licenses are substantially similar in intent and implementation. All of these software packages originated in academic institutions interested in the widest possible technology transfer (University of California, MIT, and UIUC).

Examples of free software

Free software badge

Notable free software:

• Operating systems: Linux, BSD, Darwin, and OpenSolaris.
• GCC compilers, GDB debugger and C libraries.
• Servers: BIND name server, Sendmail mail transport, Apache web server, and Samba file server.
• Relational database systems: MySQL and PostgreSQL.
• Programming languages: Java, Perl, PHP, Python, Lua, Ruby, and Tcl.
• GUI related: X Window System, GNOME, KDE, and Xfce desktop environments.
• OpenOffice.org office suite, Mozilla and Firefox web browsers, and the GIMP graphics editor.
• Typesetting and document preparation systems TeX and LaTeX.
• ogg: free software multimedia container, used to hold ogg vorbis sound and ogg theora video.
• Text editors like vi or emacs.

The Free Software Directory is a free software project that maintains a large database of free software packages.