Free software is software which is "free as in freedom, not as in beer". Once obtained, it can be used, copied, studied, modified and redistributed. It is often made available online without charge or offline for the cost of distribution; however, this is optional. Freeware is sometimes published with source code; however, the software is non-free unless the rights to modify and redistribute modified versions of the program are guaranteed.

History

• 1960s and 1970s - software was seen as an add-on supplied by mainframe vendors to make computers useful. Thus, programmers and developers frequently freely shared their software. This was especially common in large users groups, such as DECUS , the DEC (Digital Equipment Corporation) Users Group.

• Late 1970s - companies began routinely imposing restrictions on programmers with software license agreements.

• 1983 - Richard Stallman began the GNU project, founding the Free Software Foundation (FSF) two years later [1]. He introduced a "free software" definition and "copyleft", designed to ensure software freedom for all [2].

According to Stallman and the FSF, "free" software licenses grant:

• the freedom to run the program for any purpose (called "freedom 0")
• the freedom to study and modify the program ("freedom 1")
• the freedom to copy the program so you can help your neighbor ("freedom 2")
• the freedom to improve the program, and release your improvements to the public, so that the whole community benefits ("freedom 3")

Freedoms 1 and 3 require source code access. Although reverse-engineering, studying, and modifying software without source code is possible, it is extremely difficult and highly inefficient compared to modifying annotated source code.

A compliant licenses list is on the FSF web site:

"Proprietary software" is distributed under more restrictive software licenses. Copyright law restricts modification, duplication and redistribution rights to the copyright owner; software released under a free software license rescinds most of these reserved rights.

The FSF free software definition disregards price. CDs of free software such as Linux distributions are commonly for sale. However, the CD buyer still has the free software freedoms, so it is still free software. Free beer software which includes restrictions that confict with the FSF definition are considered proprietary. For example, source code may be unavailable, redistributors may be prohibited charging fees, etc.

Some people use "libre" and "gratis" to avoid the ambiguity of the word "free." However, these terms are mostly used within the free software movement and are slowly spreading.

Variations on free software as defined by the FSF:

• Copyleft licenses, the GNU General Public License being the most prominent. The author retains copyright and permits redistribution and modification under terms to ensure that all modified versions remain free.
• Public domain software-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.
• BSD-style licenses, so called because they are applied to much of the software distributed with the BSD operating systems. The author retains copyright protection solely to disclaim warranty and require proper attribution of modified works, but permits redistribution and modification in any work, even proprietary ones.

The copyright owner of copyleft-licensed software can produce and sell a version under any license, in addition to distributing the original version as free software. Many free software companies use this technique; this does not restrict any of the rights granted to the users of the copyleft version.

Examples and evolution

The amount of free software is large and increasing; this is often referred to as the free software movement.

Notable free software projects:

• Operating system kernels:
  • Linux and BSD.
• GCC compilers, GDB debugger and C libraries.
• Servers:
  • BIND name server, Sendmail mail transport, Apache web server, Samba file server.
• Relational database systems:
  • MySQL and PostgreSQL.
• Programming languages:
  • Perl, Python, Tcl and PHP.
• GUI related:
  • X Window System, GNOME and KDE desktop environments.
• OpenOffice.org office suite, Mozilla web browser and the GIMP graphics editor.
• TeX and LaTeX typesetting and document preparation systems.

Like all free software, these projects' software licenses grant people all the freedoms discussed above. However, license technicalities makes combining programs by mixing source code or directly linking binaries problematic, unless the applications' licenses are compatible. Programs indirectly connected together may avoid this problem. Much free software supports the non-free Microsoft Windows platform, and non-free software can support free platforms, although purists prefer all-free software on a free platform such as GNU/Linux.

Free software packages constitute a software ecosystem where software provides services, resulting in mutual benefit: for instance, the Apache web server handling the HTTP protocol, using mod_python to provide dynamic content.

Social significance

Soon after free software begins circulation, it becomes available at little to no cost. When free software spreads, its utility is constant, or even increases due to network effects. Thus, free software is a pure public good rather than a private good.

Because free software freedoms result in lower cost than proprietary software, free software is often popular in third world countries. Furthermore, the openness of free software eases internationalization.

International cooperation through free association produces most free software. The Oekonux and Hipatia projects contend free association could produce everything. Free association is also used for wiki writing, such as Wikipedia and give-away shops.

Individual Motivations

Individuals within a team typically have a wide variety of motivations.

Stances on the relationship between free software and the existing capitalist economic system:

• Competition - free software and capitialism are incompatible, so more free software results in less capitalism.
• Inter-market competition - free software is a form of competition within capitalisim. Copyright is governmental market restriction.
• Gift economy - status depends on gifts.

Relative security

There is controversy over the security of free software vs. proprietary software (a major issue being security through obscurity). A popular relative security measurement is counting 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.

See also

• Free audio software
• Free game software
• Free/Libre Open Source Software
• Free Software Foundation
• Free software licenses
• GNU General Public Licence
• GNU Project
• Open source
• Open source culture

External links

• The Free Software Definition - published by FSF
• FSF's list of free software licenses, including clarifications on often confused non-free licenses
• FSF/UNESCO directory of free software packages
• The GNU philosophy pages
• FSF's comparison of "Open Source" and "Free Software"
• An argument for free software (Charles Stross)
• Why Open Source Software / Free Software (OSS/FS)? Look at the Numbers! — David Wheeler's analysis of the advantages of OSS/FS by an exhaustive review of published studies, analyses, and news reports.
• Directory of free software and open source softwares at Framasoft's site
• Some Code to Die for. On the Birth of the Free Software Movement in 1887 — Essay by Leo Findeisen, monochrom.
• demosoftware.net — demos and documentation wiki for GNU GPL and GNU LGPL, web-based, Free Software
• Brazil: Free Software's Biggest and Best Friend
• South Korea Steps Up Linux Use in Public Sector