Free software, software libre or libre software is software provided under terms that guarantee the freedoms of its users (individually and in groups) to run it, adapt it to their needs, and redistribute it with or without changes. These freedoms are protected by granting broad permission to make use of the source code, either alone or in cooperation with other people of the user's choice. Users of free software are free in these activities, because they do not need to ask for any permission; and they are are not restricted in activities through restrictive proprietary licenses (e.g. copy-restriction), or requirements of having to agree to restrictive terms of others (e.g. non-disclosure agreements), and they are not already restricted from the outset (e.g. through deliberate non-availability of source code).
The goals of Free Software (control in one's own computing and free cooperation) are reached by granting the following freedom-rights: users are free to run, copy, distribute, study, change and improve the software; these freedoms are explicitly granted and not suppressed (as is the case with proprietary software). Thus, free software is a matter of liberty, not price (users are free – which includes the freedom to redistribute the software, which can be done gratis or for a fee). Free software guarantees user's freedoms: to study and modify software, by the availability of the source code; as well as freedom to copy, and distribute.[repetition]
The term "free software" and its exact definition, as well as the freedom philosophy behind it, were coined and have developed since the beginning of the GNU project (to create a freedom-respecting operating system) and the founding of the Free Software Foundation (FSF) in 1985 by Richard Stallman.
Free software differs from proprietary software, which to various degree does not give the user freedoms to study, modify and share the software. Proprietary software is usually sold as a binary executable program without the source code and may have non-disclosure agreements and restrictive licenses which can make the user dependent on proprietary software that is produced only by the same provider (vendor lock-in) if the provider is the only producer of software interoperable with the one possessed by user. It is also distinct from freeware, which by definition does not require payment for use. The authors or copyright holders of freeware may retain all rights to the software; it is not necessarily permissible to reverse engineer, modify, or redistribute freeware.
The free software movement was conceived in 1983 by Richard Stallman to satisfy the need for and to give the benefit of software freedom to computer users. Stallman founded the Free Software Foundation in 1985 to provide the organizational structure to advance his free software ideas.
From 1998 onward, alternative terms for free software came into use. The most common are software libre, free and open source software (FOSS) and free, libre and open source software (FLOSS). The Software Freedom Law Center was founded in 2005 to protect and advance FLOSS. Commercial software may sometimes offer freedoms that are typical of free and open source software.
From the 1950's up until the early 1970s, it was normal for computer users to have the software freedoms associated with free software. Software was commonly shared by individuals who used computers and by hardware manufacturers who welcomed the fact that people were making software that made their hardware useful. Organizations of users and suppliers, for example, SHARE, were formed to facilitate exchange of software. By the early 1970s, the picture changed: 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 modify software. In 1980 copyright law was extended to computer programs.
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. He developed a free software definition and the concept of "copyleft", designed to ensure software freedom for all.
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.
The FSF recommends using the term "free software" rather than "open source software" because, as they state in a paper on Free Software philosophy, the latter term and the associated marketing campaign focuses on the technical issues of software development, avoiding the issue of user freedoms. The FSF also notes that "Open Source" has exactly one specific meaning in common English, namely that "you can look at the source code." Stallman states that while the term "Free Software" can lead to two different interpretations, one of them is consistent with FSF definition of Free Software so there is at least some chance that it could be understood properly, unlike the term "Open Source". "Libre" is often used to avoid the ambiguity of the word "free" in English language; see Gratis versus libre.
The first formal definition of free software was published by FSF in February 1986. 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. (The numbering begins with zero since many computer systems use zero-based numbering.)
- Freedom 0: The freedom to run the program for any purpose.
- Freedom 1: The freedom to study how the program works, and change it to make it do what you wish.
- Freedom 2: The freedom to redistribute copies so you can help your neighbor.
- Freedom 3: The freedom to improve the program, and release your improvements (and modified versions in general) 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 can range from highly impractical to nearly impossible.
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, the Free Software Foundation says: "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'". See Gratis versus libre.
In the late 1990s, other groups published their own definitions that describe an almost identical set of software. The most notable are Debian Free Software Guidelines published in 1997, 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 use the software as they wish, without being legally forced to provide the source code. Their view is that this permissive approach is more free. The Kerberos, X11, and Apache software licenses are substantially similar in intent and implementation.
The Free Software Directory maintains a large database of free software packages. Some of the best-known examples include the Linux Kernel, the BSD and GNU/Linux operating systems, the GNU Compiler Collection and C library; the MySQL relational database; the Apache web server; and the Sendmail mail transport agent. Other influential examples include the emacs text editor; the GIMP raster drawing and image editor; the X Window System graphical-display system; the LibreOffice office suite; and the TeX and LaTeX typesetting systems.
All free software licenses must grant users 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 falls under 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:
The FSF list is not prescriptive: free licenses can exist that the FSF has not heard about, or considered important enough to write about. So it's possible for a license to be free and not in the FSF list. The OSI list only lists licenses that have been submitted, considered and approved. All Open Source licenses must meet the Open Source Definition in order to be officially recognized as open source software. Free software on the other hand is a more informal classification that does not rely on official recognition. Nevertheless, software licensed under licenses that do not meet the Free Software Definition cannot rightly be considered free software.
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.
It is rare that a license announced as being in-compliance with the FSF guidelines does not also meet the Open Source Definition, although the reverse is not necessarily true (for example, the NASA Open Source Agreement is an OSI-approved license, but non-free according to FSF).
There are different categories of free software.
- Public domain software: the copyright has expired, the work was not copyrighted, or the author has released the software onto the public domain (in countries where this is possible). Since public-domain software lacks copyright protection, it may be freely incorporated into any work, whether proprietary or free.
- Permissive licenses, also called BSD-style because they are applied to much of the software distributed with the BSD operating systems: these licenses are also known as copyfree as they have no restrictions on distribution. The author retains copyright solely to disclaim warranty and require proper attribution of modified works, and permits redistribution and any modification, even closed source ones.
- Copyleft licenses, with the GNU General Public License being the most prominent: the author retains copyright and permits redistribution under the restriction that 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. This is also known as a Viral license. Due to the restriction on distribution not everyone considers this type of license to be free.
Security and reliability
There is debate over the 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 to use relative counting of known unpatched security flaws. Generally, users of this method advise avoiding products that lack fixes for known security flaws, at least until a fix is available.
Free software advocates say 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, (This is called "Security Through Disclosure") and proprietary software can have undisclosed flaws discoverable by or known to malicious users. As users can analyse and trace the source code, many more people with no commercial constraints can inspect the code and find bugs and loopholes than a corporation would find practicable. According to Richard Stallman, user access to the source code makes deploying free software with undesirable hidden spyware functionality far more difficult than for proprietary software. As examples, he named two aspects of Windows XP that reveal information to Microsoft, which were discovered in spite of the estimated 50 million or more lines of Windows code having not been available to individual users for personal auditing.
Since free software may be freely redistributed, it is generally available at little or no fee. Free software business models are usually based on adding value such as applications, support, training, customization, integration, or certification. At the same time, some business models that work with proprietary software are not compatible with free software, such as those that depend on the user to pay for a license in order to lawfully use the software product.
Fees are usually charged for distribution on compact discs and bootable USB drives, or for services of installing or maintaining the operation of free software. Development of large, commercially used free software is often funded by a combination of user donations, corporate contributions, and tax money. The SELinux project at the United States National Security Agency is an example of a federally funded free software project.
In practice, for software to be distributed as free software, the source code, a human-readable form of the program from which an executable form is produced, must be accessible to the recipient along with a document granting the same rights to free software under which it was published. Such a document is either a free software license or the release of the source code into the public domain.
The Free Software Foundation encourages selling free software. As the Foundation has written, "Distributing free software is an opportunity to raise funds for development. Don't waste it!". For example the GNU GPL that is the Free Software Foundation's license states that "[the user] may charge any price or no price for each copy that you convey, and you may offer support or warranty protection for a fee."
It is a common misbelief however that consumers shouldn't or aren't allowed to redistribute software under the GPL for profit, and some opposing parties state such notions. For example Microsoft CEO Steve Ballmer stated in 2001 that "Open source is not available to commercial companies. The way the license is written, if you use any open-source software, you have to make the rest of your software open source." This misunderstanding is based on a requirement of copyleft licenses (like the GPL) that if you distribute modified versions of software, you must release the source and use the same license. This requirement does not extend to other software from the same developer. The claim of incompatibility between commercial companies and Free Software is also a misunderstanding. There are several large companies, e.g. Red Hat and IBM, that do substantial commercial business in the development of Free Software.
Economical aspects and adoption
Free software played a significant part in the development of the Internet, the World Wide Web and the infrastructure of dot-com companies. 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.)
The economic viability of free software has been recognized 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.
Under the free software business model[further explanation needed], 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 no cost and can result in permanently lower TCO 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.
Criticism and controversies
||This article's Criticism or Controversy section may compromise the article's neutral point of view of the subject. (January 2013)|
In 2006, OpenBSD started the first campaign against the use of binary blobs, in kernels. Blobs are usually freely distributable device drivers for hardware from vendors that do not reveal driver source code to users or developers. This restricts the users' freedom effectively to modify the software and distribute modified versions. Also, since the blobs are undocumented and may have 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 Linux based distribution with all the binary blobs removed. The project received support from the Free Software Foundation and stimulated the creation, headed by the Free Software Foundation Latin America, of the Linux-libre kernel. As of October 2012, Trisquel is the most popular FSF endorsed GNU/Linux distribution ranked by Distrowatch (over 12 months).
Larry McVoy invited high-profile free software projects to use his proprietary distributed version control 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.
Following the apparent reverse engineering of BitKeeper's protocols, McVoy withdrew permission for gratis use by free software projects. Linus Torvalds quickly developed a free software replacement called Git, while fellow Linux kernel contributor Matt Mackall developed another free software replacement called Mercurial. The Linux kernel community eventually settled on Git for its own development process, while some other free software projects have chosen Mercurial.
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. FSF included as a result of this deal conditions in the GPL to prevent deals like it in the future.
Eric S. Raymond argues that the term free software is too ambiguous and intimidating for the business community. Raymond promotes the term open source software as a more friendly alternative for the business and corporate world.
- Definition of Free Cultural Works
- Free content
- Libre knowledge
- Open format
- Open standard
- Outline of free software
- Category:Free software lists and comparisons
- List of formerly proprietary software
- List of free software project directories
- List of free software for Web 2.0 Services
- Free Software Movement (gnu.org)
- Philosophy of the GNU Project (gnu.org)
- What is free software (fsf.org)
- Free Software Free Society: Selected Essays of Richard M. Stallman, 2nd Edition
- Selling Free Software (gnu.org)
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- Definition and philosophy
- Free Software Movement; Philosophy and Intro; The Free Software Definition (gnu.org)
- What is free software? (fsf.org)
- Categories of free and nonfree software (gnu.org)
- Freedom for Users, Not for Software (Benjamin Mako Hill)
- What Does Free Mean? or What do you mean by Free Software? (debian.org)
- Video and audio presentations on Free Software (top link)
- Free as in Freedom (originally the oggcast of the Software Freedom Law Center, it includes a focus on law issues, and other topics)