Is open source software free?

Free and open-source software (FOSS) is software that can be classified as both free software and open-source software. That is, anyone is freely licensed to use, copy, study, and change the software in any way, and the source code is openly shared so that people are encouraged to voluntarily improve the design of the software. This is in contrast to proprietary software, where the software is under restrictive copyright licensing and the source code is usually hidden from the users.

Free and open-source software

FOSS maintains the software user's civil liberty rights (see the Four Essential Freedoms, below). Other benefits of using FOSS can include decreased software costs, increased security and stability (especially in regard to malware), protecting privacy, education, and giving users more control over their own hardware. Free and open-source operating systems such as Linux and descendants of BSD are widely utilized today, powering millions of servers, desktops, smartphones (e.g. Android), and other devices. Free-software licenses and open-source licenses are used by many software packages. The free-software movement and the open-source software movement are online social movements behind widespread production and adoption of FOSS.

"Free and open-source software" (FOSS) is an umbrella term for software that is simultaneously considered both Free software and open-source software. FOSS (free and open-source software) allows the user to inspect the source code and provides a high level of control of the software's functions compared to proprietary software. The term "free software" does not refer to the monetary cost of the software at all, but rather whether the license maintains the software user's civil liberties ("free” as in “free speech,” not as in “free beer”). There are a number of related terms and abbreviations for free and open-source software (FOSS or F/OSS), or free/libre and open-source software (FLOSS or F/LOSS -- FLOSS is the FSF-preferred term).

Although there is almost a complete overlap between free-software licenses and open-source-software licenses, there is a strong philosophical disagreement between the advocates of these two positions. The terminology of FOSS or "Free and Open-source software" was created to be a neutral on these philosophical disagreements between the FSF and OSI and have a single unified term that could refer to both concepts.

As the Free Software Foundation (FSF) explains the philosophical difference between free software and open-source software: "The two terms describe almost the same category of software, but they stand for views based on fundamentally different values. Open-source is a development methodology; free software is a social movement. For the free-software movement, free software is an ethical imperative, essential respect for the users' freedom. By contrast, the philosophy of open-source considers issues in terms of how to make software “better”—in a practical sense only." In parallel to this the Open Source Initiative (OSI) considers many free-software licenses to also be open source. These include the latest versions of the FSF's three main licenses: the GPL, the Lesser General Public License (LGPL), and the GNU Affero General Public License (AGPL).

Richard Stallman's Free Software Definition, adopted by the Free Software Foundation (FSF), defines free software as a matter of liberty not price, and it upholds the Four Essential Freedoms. The earliest-known publication of the definition of his free-software idea was in the February 1986 edition of the FSF's now-discontinued GNU's Bulletin publication. The canonical source for the document is in the philosophy section of the GNU Project website. As of August 2017, it is published there in 40 languages.

To meet the definition of "free software", the FSF requires the software's licensing rights what the FSF respect the civil liberties / human rights of what the FSF calls the software user's "Four Essential Freedoms".The open-source-software definition is used by the Open Source Initiative (OSI) to determine whether a software license qualifies for the organization's insignia for Open-source software. 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 Essential Freedoms of free software from the Free Software Foundation, which were only later available on the web. Perens subsequently stated that he felt Eric Raymond's promotion of Open-source unfairly overshadowed the Free Software Foundation's efforts and reaffirmed his support for Free software. In the following 2000s, he spoke about open source again.

In the 1950s through the 1980s, it was common for computer users to have the source code for all programs they used, and the permission and ability to modify it for their own use. Software, including source code, was commonly shared by individuals who used computers, often as public domain software. Most companies had a business model based on hardware sales, and provided or bundled software with hardware, free of charge.

By the late 1960s, the prevailing business model around software was changing. A growing and evolving software industry was competing with the hardware manufacturer's bundled software products; rather than funding software development from hardware revenue, these new companies were selling software directly. Leased machines required software support while providing no revenue for software, and some customers who were able to better meet their own needs did not want the costs of 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 was still being provided without monetary cost and license restriction, there was a growing amount of software that was only at a monetary cost with restricted licensing. In the 1970s and early 1980s, some parts of the software industry began using technical measures (such as distributing only binary copies of computer programs) to prevent computer users from being able to use reverse engineering techniques to study and customize software they had paid for. In 1980, the copyright law was extended to computer programs in the United States—previously, computer programs could be considered ideas, procedures, methods, systems, and processes, which are not copyrightable.

Early on, closed-source software was uncommon until the mid-1970s to the 1980s, when IBM implemented in 1983 an "object code only" policy, no longer distributing source code.

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 included significant explanation of the GNU philosophy, "Free Software Definition" and "copyleft" ideas. The FSF takes the position that the fundamental issue Free software addresses is an ethical one—to ensure software users can exercise what it calls "The Four Essential Freedoms".

The Linux kernel, created by Linus Torvalds, was released as freely modifiable source code in 1991. Initially, Linux was not released under either a Free software or an Open-source software license. However, with version 0.12 in February 1992, he relicensed the project under the GNU General Public License.

FreeBSD and NetBSD (both derived from 386BSD) were released as Free software when the USL v. BSDi lawsuit was settled out of court in 1993. OpenBSD forked from NetBSD in 1995. Also in 1995, The Apache HTTP Server, commonly referred to as Apache, was released under the Apache License 1.0.

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 the FSF's Free software ideas and perceived 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 sharing and collaborating on software 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 the 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, commercial software vendors 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 some software corporations. For many years FOSS played a niche role outside of the mainstream of private software development. However the success of FOSS Operating Systems such as GNU/Linux, BSD and the companies based on FOSS such as Red Hat, has changed the software industry's attitude and there has been a dramatic shift in the corporate philosophy concerning the development of Free and Open-source software (FOSS).

Users of FOSS benefit from the Four Essential Freedoms to make unrestricted use of, and to study, copy, modify, and redistribute such software with or without modification. If they would like to change the functionality of software they can bring about changes to the code and, if they wish, distribute such modified versions of the software or often − depending on the software's decision making model and its other users − even push or request such changes to be made via updates to the original software.

Manufacturers of proprietary, closed-source software are sometimes pressured to building in backdoors or other covert, undesired features into their software. Instead of having to trust software vendors users of FOSS can inspect and verify the source code themselves and can put trust on a community of volunteers and users. As proprietary code is typically hidden from public view, only the vendors themselves and hackers may be aware of any vulnerabilities in them while FOSS involves as many people as possible for exposing bugs quickly.

FOSS is often free of charge although donations are often encouraged. This also allows users to better test and compare software.

FOSS allows for better collaboration among various parties and individuals with the goal of developing the most efficient software for its users or use-cases while proprietary software is typically meant to generate profits. Furthermore, in many cases more organizations and individuals contribute to such projects than to proprietary software. It has been shown that technical superiority is typically the primary reason why companies choose open source software.

According to Linus's Law the more people who can see and test a set of code, the more likely any flaws will be caught and fixed quickly. However, this does not guarantee a high level of participation. Having a grouping of full-time professionals behind a commercial product can in some cases be superior to FOSS.

Furthermore, publicized source code might make it easier for hackers to find vulnerabilities in it and write exploits. This however assumes that such malicious hackers are more effective than white hat hackers which responsibly disclose or help fix the vulnerabilities, that no code leaks or exfiltrations occur and that reverse engineering of proprietary code is a hindrance of significance for malicious hackers.

Sometimes, FOSS is not compatible with proprietary hardware or specific software. This is often due to manufacturers obstructing FOSS such as by not disclosing the interfaces or other specifications needed for members of the FOSS movement to write drivers for their hardware − for instance as they wish customers to run only their own proprietary software or as they might benefit from partnerships.

While FOSS can be superior to proprietary equivalents in terms of software features and stability, in many cases FOSS has more unfixed bugs and missing features when compared to similar commercial software. This varies per case and usually depends on the level of interest and participation in a FOSS project. Furthermore, unlike with typical commercial software missing features and bugfixes can be implemented by any party that has the relevant motivation, time and skill to do so.

There is often less certainty in FOSS projects gaining the required resources / participation for continued development than commercial software backed by companies. However companies also often abolish projects for being unprofitable and often large companies rely on and hence co-develop open source software.

As the FOSS operating system distributions of GNU/Linux has a lower market share of end users there are also fewer applications available.

GNU/Linux may require more effort or technical knowledge to set up and maintain.

In 2017, the European Commission stated that "EU institutions should become open source software users themselves, even more than they already are" and listed open source software as one of the nine key drivers of innovation, together with big data, mobility, cloud computing and the internet of things.

While copyright is the primary legal mechanism that FOSS authors use to ensure license compliance for their software, other mechanisms such as legislation, patents, and trademarks have implications as well. In response to legal issues with patents and the Digital Millennium Copyright Act (DMCA), the Free Software Foundation released version 3 of its GNU Public License in 2007 that explicitly addressed the DMCA and patent rights.

After the development of the GNU GPLv3 in 2007, the FSF (as the copyright holder of many pieces of the GNU system) updated many of the GNU programs' licenses from GPLv2 to GPLv3. On the other hand, the adoption of the new GPL version was heavily discussed in the FOSS ecosystem, several projects decided against upgrading. For instance the linux kernel, the BusyBox project, AdvFS, Blender, and as also the VLC media player decided against adopting the GPLv3.

Apple, a user of GCC and a heavy user of both DRM and patents, switched the compiler in its Xcode IDE from GCC to Clang, which is another FOSS compiler but is under a permissive license. LWN speculated that Apple was motivated partly by a desire to avoid GPLv3. The Samba project also switched to GPLv3, so Apple replaced Samba in their software suite by a closed-source, proprietary software alternative.

Leemhuis criticizes the prioritization of skilled developers who − instead of fixing issues in popular applications and desktop environments − create new, mostly redundant software to gain fame and fortune.

He also criticizes notebook manufacturers for optimizing their own products only privately or creating workarounds instead of helping fix the actual causes of the many issues with GNU/Linux on notebooks such as the unnecessary power consumption.

Mergers have affected major open-source software. Sun Microsystems (Sun) acquired MySQL AB, owner of the popular open-source MySQL database, in 2008.

Oracle in turn purchased Sun in January, 2010, acquiring their copyrights, patents, and trademarks. Thus, Oracle became the owner of both 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. Partly in response to uncertainty about the future of MySQL, the FOSS community forked the project into new database systems outside of Oracle's control. These include MariaDB, Percona, and Drizzle. All of these have distinct names; they are distinct projects and cannot use the trademarked name MySQL.

In August, 2010, Oracle sued Google, claiming that its use of Java in Android infringed on Oracle's copyrights and patents. The Oracle v. Google case ended in May 2012, with the finding that Google did not infringe on Oracle's patents, and the trial judge ruled that the structure of the Java APIs used by Google was not copyrightable. The jury found that Google infringed a small number of copied files, but the parties stipulated that Google would pay no damages. Oracle appealed to the Federal Circuit, and Google filed a cross-appeal on the literal copying claim.

By defying ownership regulations in the construction and use of information − a key area of contemporary growth − the Free/Open Source Software (FOSS) movement counters neoliberalism and privatization in general.

By realizing the historical potential of an "economy of abundance" for the new digital world FOSS may lay down a plan for political resistance or show the way towards a potential transformation of capitalism.

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.

Free and open-source software

Free and open-source software (FOSS) is software that can be classified as both free software and open-source software. That is, anyone is freely licensed to use, copy, study, and change the software in any way, and the source code is openly shared so that people are encouraged to voluntarily improve the design of the software. This is in contrast to proprietary software, where the software is under restrictive copyright licensing and the source code is usually hidden from the users.

Although there is almost a complete overlap between free-software licenses and open-source-software licenses, there is a strong philosophical disagreement between the advocates of these two positions. The terminology of FOSS or "Free and Open-source software" was created to be a neutral on these philosophical disagreements between the FSF and OSI and have a single unified term that could refer to both concepts.

Richard Stallman's Free Software Definition, adopted by the Free Software Foundation (FSF), defines free software as a matter of liberty not price, and it upholds the Four Essential Freedoms. The earliest-known publication of the definition of his free-software idea was in the February 1986 edition of the FSF's now-discontinued GNU's Bulletin publication. The canonical source for the document is in the philosophy section of the GNU Project website. As of August 2017, it is published there in 40 languages.

In the 1950s through the 1980s, it was common for computer users to have the source code for all programs they used, and the permission and ability to modify it for their own use. Software, including source code, was commonly shared by individuals who used computers, often as public domain software. Most companies had a business model based on hardware sales, and provided or bundled software with hardware, free of charge.

Early on, closed-source software was uncommon until the mid-1970s to the 1980s, when IBM implemented in 1983 an "object code only" policy, no longer distributing source code.

The Linux kernel, created by Linus Torvalds, was released as freely modifiable source code in 1991. Initially, Linux was not released under either a Free software or an Open-source software license. However, with version 0.12 in February 1992, he relicensed the project under the GNU General Public License.

FreeBSD and NetBSD (both derived from 386BSD) were released as Free software when the USL v. BSDi lawsuit was settled out of court in 1993. OpenBSD forked from NetBSD in 1995. Also in 1995, The Apache HTTP Server, commonly referred to as Apache, was released under the Apache License 1.0.

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.

Users of FOSS benefit from the Four Essential Freedoms to make unrestricted use of, and to study, copy, modify, and redistribute such software with or without modification. If they would like to change the functionality of software they can bring about changes to the code and, if they wish, distribute such modified versions of the software or often − depending on the software's decision making model and its other users − even push or request such changes to be made via updates to the original software.

Manufacturers of proprietary, closed-source software are sometimes pressured to building in backdoors or other covert, undesired features into their software. Instead of having to trust software vendors users of FOSS can inspect and verify the source code themselves and can put trust on a community of volunteers and users. As proprietary code is typically hidden from public view, only the vendors themselves and hackers may be aware of any vulnerabilities in them while FOSS involves as many people as possible for exposing bugs quickly.

FOSS is often free of charge although donations are often encouraged. This also allows users to better test and compare software.

FOSS allows for better collaboration among various parties and individuals with the goal of developing the most efficient software for its users or use-cases while proprietary software is typically meant to generate profits. Furthermore, in many cases more organizations and individuals contribute to such projects than to proprietary software. It has been shown that technical superiority is typically the primary reason why companies choose open source software.

According to Linus's Law the more people who can see and test a set of code, the more likely any flaws will be caught and fixed quickly. However, this does not guarantee a high level of participation. Having a grouping of full-time professionals behind a commercial product can in some cases be superior to FOSS.

Furthermore, publicized source code might make it easier for hackers to find vulnerabilities in it and write exploits. This however assumes that such malicious hackers are more effective than white hat hackers which responsibly disclose or help fix the vulnerabilities, that no code leaks or exfiltrations occur and that reverse engineering of proprietary code is a hindrance of significance for malicious hackers.

Sometimes, FOSS is not compatible with proprietary hardware or specific software. This is often due to manufacturers obstructing FOSS such as by not disclosing the interfaces or other specifications needed for members of the FOSS movement to write drivers for their hardware − for instance as they wish customers to run only their own proprietary software or as they might benefit from partnerships.

While FOSS can be superior to proprietary equivalents in terms of software features and stability, in many cases FOSS has more unfixed bugs and missing features when compared to similar commercial software. This varies per case and usually depends on the level of interest and participation in a FOSS project. Furthermore, unlike with typical commercial software missing features and bugfixes can be implemented by any party that has the relevant motivation, time and skill to do so.

There is often less certainty in FOSS projects gaining the required resources / participation for continued development than commercial software backed by companies. However companies also often abolish projects for being unprofitable and often large companies rely on and hence co-develop open source software.

As the FOSS operating system distributions of GNU/Linux has a lower market share of end users there are also fewer applications available.

GNU/Linux may require more effort or technical knowledge to set up and maintain.

In 2017, the European Commission stated that "EU institutions should become open source software users themselves, even more than they already are" and listed open source software as one of the nine key drivers of innovation, together with big data, mobility, cloud computing and the internet of things.

While copyright is the primary legal mechanism that FOSS authors use to ensure license compliance for their software, other mechanisms such as legislation, patents, and trademarks have implications as well. In response to legal issues with patents and the Digital Millennium Copyright Act (DMCA), the Free Software Foundation released version 3 of its GNU Public License in 2007 that explicitly addressed the DMCA and patent rights.

After the development of the GNU GPLv3 in 2007, the FSF (as the copyright holder of many pieces of the GNU system) updated many of the GNU programs' licenses from GPLv2 to GPLv3. On the other hand, the adoption of the new GPL version was heavily discussed in the FOSS ecosystem, several projects decided against upgrading. For instance the linux kernel, the BusyBox project, AdvFS, Blender, and as also the VLC media player decided against adopting the GPLv3.

Apple, a user of GCC and a heavy user of both DRM and patents, switched the compiler in its Xcode IDE from GCC to Clang, which is another FOSS compiler but is under a permissive license. LWN speculated that Apple was motivated partly by a desire to avoid GPLv3. The Samba project also switched to GPLv3, so Apple replaced Samba in their software suite by a closed-source, proprietary software alternative.

Leemhuis criticizes the prioritization of skilled developers who − instead of fixing issues in popular applications and desktop environments − create new, mostly redundant software to gain fame and fortune.

He also criticizes notebook manufacturers for optimizing their own products only privately or creating workarounds instead of helping fix the actual causes of the many issues with GNU/Linux on notebooks such as the unnecessary power consumption.

Mergers have affected major open-source software. Sun Microsystems (Sun) acquired MySQL AB, owner of the popular open-source MySQL database, in 2008.

In August, 2010, Oracle sued Google, claiming that its use of Java in Android infringed on Oracle's copyrights and patents. The Oracle v. Google case ended in May 2012, with the finding that Google did not infringe on Oracle's patents, and the trial judge ruled that the structure of the Java APIs used by Google was not copyrightable. The jury found that Google infringed a small number of copied files, but the parties stipulated that Google would pay no damages. Oracle appealed to the Federal Circuit, and Google filed a cross-appeal on the literal copying claim.

By defying ownership regulations in the construction and use of information − a key area of contemporary growth − the Free/Open Source Software (FOSS) movement counters neoliberalism and privatization in general.

By realizing the historical potential of an "economy of abundance" for the new digital world FOSS may lay down a plan for political resistance or show the way towards a potential transformation of capitalism.

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.

Free and open-source software

Free and open-source software (FOSS) is software that can be classified as both free software and open-source software. That is, anyone is freely licensed to use, copy, study, and change the software in any way, and the source code is openly shared so that people are encouraged to voluntarily improve the design of the software. This is in contrast to proprietary software, where the software is under restrictive copyright licensing and the source code is usually hidden from the users.

Although there is almost a complete overlap between free-software licenses and open-source-software licenses, there is a strong philosophical disagreement between the advocates of these two positions. The terminology of FOSS or "Free and Open-source software" was created to be a neutral on these philosophical disagreements between the FSF and OSI and have a single unified term that could refer to both concepts.

Richard Stallman's Free Software Definition, adopted by the Free Software Foundation (FSF), defines free software as a matter of liberty not price, and it upholds the Four Essential Freedoms. The earliest-known publication of the definition of his free-software idea was in the February 1986 edition of the FSF's now-discontinued GNU's Bulletin publication. The canonical source for the document is in the philosophy section of the GNU Project website. As of August 2017, it is published there in 40 languages.

In the 1950s through the 1980s, it was common for computer users to have the source code for all programs they used, and the permission and ability to modify it for their own use. Software, including source code, was commonly shared by individuals who used computers, often as public domain software. Most companies had a business model based on hardware sales, and provided or bundled software with hardware, free of charge.

Early on, closed-source software was uncommon until the mid-1970s to the 1980s, when IBM implemented in 1983 an "object code only" policy, no longer distributing source code.

The Linux kernel, created by Linus Torvalds, was released as freely modifiable source code in 1991. Initially, Linux was not released under either a Free software or an Open-source software license. However, with version 0.12 in February 1992, he relicensed the project under the GNU General Public License.

FreeBSD and NetBSD (both derived from 386BSD) were released as Free software when the USL v. BSDi lawsuit was settled out of court in 1993. OpenBSD forked from NetBSD in 1995. Also in 1995, The Apache HTTP Server, commonly referred to as Apache, was released under the Apache License 1.0.

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.

Users of FOSS benefit from the Four Essential Freedoms to make unrestricted use of, and to study, copy, modify, and redistribute such software with or without modification. If they would like to change the functionality of software they can bring about changes to the code and, if they wish, distribute such modified versions of the software or often − depending on the software's decision making model and its other users − even push or request such changes to be made via updates to the original software.

Manufacturers of proprietary, closed-source software are sometimes pressured to building in backdoors or other covert, undesired features into their software. Instead of having to trust software vendors users of FOSS can inspect and verify the source code themselves and can put trust on a community of volunteers and users. As proprietary code is typically hidden from public view, only the vendors themselves and hackers may be aware of any vulnerabilities in them while FOSS involves as many people as possible for exposing bugs quickly.

FOSS is often free of charge although donations are often encouraged. This also allows users to better test and compare software.

FOSS allows for better collaboration among various parties and individuals with the goal of developing the most efficient software for its users or use-cases while proprietary software is typically meant to generate profits. Furthermore, in many cases more organizations and individuals contribute to such projects than to proprietary software. It has been shown that technical superiority is typically the primary reason why companies choose open source software.

According to Linus's Law the more people who can see and test a set of code, the more likely any flaws will be caught and fixed quickly. However, this does not guarantee a high level of participation. Having a grouping of full-time professionals behind a commercial product can in some cases be superior to FOSS.

Furthermore, publicized source code might make it easier for hackers to find vulnerabilities in it and write exploits. This however assumes that such malicious hackers are more effective than white hat hackers which responsibly disclose or help fix the vulnerabilities, that no code leaks or exfiltrations occur and that reverse engineering of proprietary code is a hindrance of significance for malicious hackers.

Sometimes, FOSS is not compatible with proprietary hardware or specific software. This is often due to manufacturers obstructing FOSS such as by not disclosing the interfaces or other specifications needed for members of the FOSS movement to write drivers for their hardware − for instance as they wish customers to run only their own proprietary software or as they might benefit from partnerships.

While FOSS can be superior to proprietary equivalents in terms of software features and stability, in many cases FOSS has more unfixed bugs and missing features when compared to similar commercial software. This varies per case and usually depends on the level of interest and participation in a FOSS project. Furthermore, unlike with typical commercial software missing features and bugfixes can be implemented by any party that has the relevant motivation, time and skill to do so.

There is often less certainty in FOSS projects gaining the required resources / participation for continued development than commercial software backed by companies. However companies also often abolish projects for being unprofitable and often large companies rely on and hence co-develop open source software.

As the FOSS operating system distributions of GNU/Linux has a lower market share of end users there are also fewer applications available.

GNU/Linux may require more effort or technical knowledge to set up and maintain.

In 2017, the European Commission stated that "EU institutions should become open source software users themselves, even more than they already are" and listed open source software as one of the nine key drivers of innovation, together with big data, mobility, cloud computing and the internet of things.

While copyright is the primary legal mechanism that FOSS authors use to ensure license compliance for their software, other mechanisms such as legislation, patents, and trademarks have implications as well. In response to legal issues with patents and the Digital Millennium Copyright Act (DMCA), the Free Software Foundation released version 3 of its GNU Public License in 2007 that explicitly addressed the DMCA and patent rights.

After the development of the GNU GPLv3 in 2007, the FSF (as the copyright holder of many pieces of the GNU system) updated many of the GNU programs' licenses from GPLv2 to GPLv3. On the other hand, the adoption of the new GPL version was heavily discussed in the FOSS ecosystem, several projects decided against upgrading. For instance the linux kernel, the BusyBox project, AdvFS, Blender, and as also the VLC media player decided against adopting the GPLv3.

Apple, a user of GCC and a heavy user of both DRM and patents, switched the compiler in its Xcode IDE from GCC to Clang, which is another FOSS compiler but is under a permissive license. LWN speculated that Apple was motivated partly by a desire to avoid GPLv3. The Samba project also switched to GPLv3, so Apple replaced Samba in their software suite by a closed-source, proprietary software alternative.

Leemhuis criticizes the prioritization of skilled developers who − instead of fixing issues in popular applications and desktop environments − create new, mostly redundant software to gain fame and fortune.

He also criticizes notebook manufacturers for optimizing their own products only privately or creating workarounds instead of helping fix the actual causes of the many issues with GNU/Linux on notebooks such as the unnecessary power consumption.

Mergers have affected major open-source software. Sun Microsystems (Sun) acquired MySQL AB, owner of the popular open-source MySQL database, in 2008.

In August, 2010, Oracle sued Google, claiming that its use of Java in Android infringed on Oracle's copyrights and patents. The Oracle v. Google case ended in May 2012, with the finding that Google did not infringe on Oracle's patents, and the trial judge ruled that the structure of the Java APIs used by Google was not copyrightable. The jury found that Google infringed a small number of copied files, but the parties stipulated that Google would pay no damages. Oracle appealed to the Federal Circuit, and Google filed a cross-appeal on the literal copying claim.

By defying ownership regulations in the construction and use of information − a key area of contemporary growth − the Free/Open Source Software (FOSS) movement counters neoliberalism and privatization in general.

By realizing the historical potential of an "economy of abundance" for the new digital world FOSS may lay down a plan for political resistance or show the way towards a potential transformation of capitalism.

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.

The open-source movement is branched from the free-software movement which began in the late 80s with the launching of the GNU project by Richard Stallman. Stallman is regarded within the open-source community as sharing a key role in the conceptualization of freely-shared source code for software development. The term "free software" in the free software movement is meant to imply freedom of software exchange and modification. The term does not refer to any monetary freedom. Both the free-software movement and the open-source movement share this view of free exchange of programming code, and this is often why both of the movements are sometimes referenced in literature as part of the FOSS or "Free and Open Software" or FLOSS "Free/Libre Open-Source" communities.

Open-source-software movement

The open-source-software movement is a movement that supports the use of open-source licenses for some or all software, a part of the broader notion of open collaboration. The open-source movement was started to spread the concept/idea of open-source software.
Programmers who support the open-source-movement philosophy contribute to the open-source community by voluntarily writing and exchanging programming code for software development. The term "open source" requires that no one can discriminate against a group in not sharing the edited code or hinder others from editing their already-edited work. This approach to software development allows anyone to obtain and modify open-source code. These modifications are distributed back to the developers within the open-source community of people who are working with the software. In this way, the identities of all individuals participating in code modification are disclosed and the transformation of the code is documented over time. This method makes it difficult to establish ownership of a particular bit of code but is in keeping with the open-source-movement philosophy. These goals promote the production of high-quality programs as well as working cooperatively with other similarly-minded people to improve open-source technology. This led to software such as MediaWiki, the software with which the Wikipedia website is built.

The label "open source" was created and adopted by a group of people in the free-software movement at a strategy session held at Palo Alto, California, in reaction to Netscape's January 1998 announcement of a source-code release for Navigator. One of the reasons behind using the term was that "the [advantage] of using the term open source [is] that the business world usually tries to keep free technologies from being installed." Those people who adopted the term used the opportunity before the release of Navigator's source code to free themselves of the ideological and confrontational connotations of the term "free software". Later in February 1998, Bruce Perens and Eric S. Raymond founded an organization called Open Source Initiative (OSI) "as an educational, advocacy, and stewardship organization at a cusp moment in the history of that culture."

In the beginning, a difference between hardware and software did not exist. The user and programmer of a computer were one and the same. When the first commercial electronic computer was introduced by IBM in 1952, the machine was hard to maintain and expensive. Putting the price of the machine aside, it was the software that caused the problem when owning one of these computers. Then in 1952, a collaboration of all the owners of the computer got together and created a set of tools. The collaboration of people were in a group called PACT (The Project for the Advancement of Coding techniques). After passing this hurdle, in 1956, the Eisenhower administration decided to put restrictions on the types of sales AT&T could make. This did not stop the inventors from developing new ideas of how to bring the computer to the mass population. The next step was making the computer more affordable which slowly developed through different companies. Then they had to develop software that would host multiple users. MIT computation center developed one of the first systems, CTSS (Compatible Time-Sharing System). This laid the foundation for many more systems, and what we now call the open-source software movement.

These movements share fundamental differences in the view on open software. The main, factionalizing difference between the groups is the relationship between open-source and proprietary software. Often, makers of proprietary software, such as Microsoft, may make efforts to support open-source software to remain competitive. Members of the open-source community are willing to coexist with the makers of proprietary software and feel that the issue of whether software is open source is a matter of practicality.

In contrast, members of the free-software community maintain the vision that all software is a part of freedom of speech and that proprietary software is unethical and unjust. The free-software movement openly champions this belief through talks that denounce proprietary software. As a whole, the community refuses to support proprietary software. Further there are external motivations for these developers. One motivation is that, when a programmer fixes a bug or makes a program it benefits others in an open-source environment. Another motivation is that a programmer can work on multiple projects that they find interesting and enjoyable. Programming in the open-source world can also lead to commercial job offers or entrance into the venture capital community. These are just a few reasons why open-source programmers continue to create and advance software.

While cognizant of the fact that both, the free-software movement and the open-source movement, share similarities in practical recommendations regarding open source, the free-software movement fervently continues to distinguish themselves from the open-source movement entirely. The free-software movement maintains that it has fundamentally different attitudes towards the relationship between open-source and proprietary software. The free-software community does not view the open-source community as their target grievance, however. Their target grievance is proprietary software itself.

The open-source movement has faced a number of legal challenges. Companies that manage open-source products have some difficulty securing their trademarks.
For example, the scope of "implied license" conjecture remains unclear and can compromise an enterprise’s ability to patent productions made with open-source software. Another example is the case of companies offering add-ons for purchase; licensees who make additions to the open-source code that are similar to those for purchase may have immunity from patent suits.

In the court case "Jacobsen v. Katzer", the plaintiff sued the defendant for failing to put the required attribution notices in his modified version of the software, thereby violating license. The defendant claimed Artistic License in not adhering to the conditions of the software’s use, but the wording of the attribution notice decided that this was not the case. "Jacobsen v Katzer" established open-source software’s equality to proprietary software in the eyes of the law.

In a court case accusing Microsoft of being a monopoly, Linux and open-source software was introduced in court to prove that Microsoft had valid competitors and was grouped in with Apple.

There are resources available for those involved open-source projects in need of legal advice. The Software Freedom Law Center features a primer on open-source legal issues. International Free and Open Source Software Law Review offers peer-reviewed information for lawyers on free-software issues.

The Open Source Initiative (OSI) was instrumental in the formalization of the open-source movement. The OSI was founded by Eric Raymond and Bruce Perens in February 1998 with the purpose of providing general education and advocacy of the open-source label through the creation of the Open Source Definition that was based on the Debian Free Software Guidelines. The OSI has become one of the main supporters and advocators of the open-source movement.

In February 1998, the open-source movement was adopted, formalized, and spearheaded by the Open Source Initiative (OSI), an organization formed to market software "as something more amenable to commercial business use" The OSI owns the trademark "Open Source"
The main tool they adopted for this was The Open Source Definition.

The open-source label was conceived at a strategy session that was held on February 3, 1998 in Palo Alto, California and on April 8 of the same year, the attendees of Tim O’Reilly’s Free Software Summit voted to promote the use of the term "open source".

Overall, the software developments that have come out of the open-source movement have not been unique to the computer-science field, but they have been successful in developing alternatives to propriety software. Members of the open-source community improve upon code and write programs that can rival much of the propriety software that is already available.

The rhetorical discourse used in open-source movements is now being broadened to include a larger group of non-expert users as well as advocacy organizations. Several organized groups such as the Creative Commons and global development agencies have also adopted the open-source concepts according to their own aims and for their own purposes.

The factors affecting the open-source movement’s legal formalization are primarily based on recent political discussion over copyright, appropriation, and intellectual property.The open-source movement has allowed smaller businesses to participate in the global economy. Before, smaller businesses did not have access to the software needed to participate or compete in the global market. It was the larger corporations, the producers of the networks and software who had the power. "That is, individuals who have access to the software needed to create, organize, or distribute content can plug into and participate in the global community". The creation of the open-source movement has created "a degree of global computing access that might have been unthinkable in a world where proprietary was the only option." Individuals or organizations with access to an open source had the means needed to develop technical material for a variety of consumers. The open-source movement created equal opportunities for people all over the world to participate in the global economy.

Members of the open-source movement stress the importance of differentiating between open-source software and free software. Although the two issues are related, they are quite different. The open-source movement and the free-software movement are different, but they work together. Both movements strive for freedom of the Internet and dislike the idea of ownership over a website. For both open-source and free software, one can find the source code and executable component easily and for free online. The largest difference is that free software requires any changes to be submitted to the original maker for redistribution, and any derivative software must also be distributed as free software. This is mainly to keep companies from making minor changes to free software and redistributing it as their own, for a price.

A major advantage to open-source code is the ability for a variety of different people to edit and fix problems and errors that have occurred. Naturally, because there are more people who can edit the material, there are more people who can help make the information more credible and reliable.
The open-source mission statement promises better quality, higher reliability, more flexibility, lower cost, and an end to predatory vendor lock-in. They stress the importance of maintaining the Open Source Definition. This trademark creates a trusted group that connects all users and developers together. To fully understand the Open Source Definition, one must understand certain terms: Free redistribution means that there is no restriction on any party to sell or give away the software to third parties. Source Code means that the program must efficiently publicize the means of obtaining the source code. Derived works means that the program must allow certain works to be distributed under the same terms. There must be a promise of no discriminating against any certain persons or groups. All of these factors allow for the open-source movement to become available to all and easy to access, which is their overall mission.
The latest updates from the Open Source Institution took place on January 19, 2011: The OSI collaborated with the Free Software Foundation and together they updated a version of the request that they have sent to the US Department of Justice.With the growth and attention on the open-source movement, the reasons and motivations of programmers for creating code for free has been under investigation. In a paper from the 15th Annual Congress of the European Economic Association on the open-source movement, the incentives of programmers on an individual level as well as on a company or network level were analyzed. What is essentially the intellectual gift giving of talented programmers challenges the "self-interested-economic-agent paradigm," and has made both the public and economists search for an understanding of what the benefits are for programmers.

The vast majority of programmers in open-source communities are male. In a study for the European Union on free and open-source software communities, researchers found that only 1.5% of all contributors are female. Although women are generally underrepresented in computing, the percentage of women in tech professions is actually much higher, close to 25%. This discrepancy suggests that female programs are overall less likely than male programmers to participate in open-source projects.

Some research and interviews with members of open-source projects have described a male-dominated culture within open-source communities that can be unwelcoming or hostile towards females. There are an initiatives such as Outreachy that aim to support more women and other underrepresented gender identities to participate in open-source software. However, within the discussion forums of open-source projects the topic of gender diversity can be highly controversial and even inflammatory. A central vision in open-source software is that because the software is built and maintained on the merit of individual code contributions, open-source communities should act as a meritocracy. In a meritocracy, the importance of an individual in the community depends on the quality of their individual contributions and not demographic factors such as age, race, religion, or gender. Thus proposing changes to the community based on gender, for example, to make the community more inviting towards females, go against the ideal of a meritocracy by targeting certain programmers by gender and no based on their skill alone.

There is evidence that gender does impact a programmer’s perceived merit in the community. A 2016 study identified the gender of over one million programmers on GitHub, by linking the programmer’s GitHub account to their other social media accounts. Between male and female programmers, the researchers found that female programmers were actually "more" "likely" to have their pull requests accepted into the project than male programmers, however only when the female had a gender-neutral profile. When females had profiles with a name or image that identified them as female, they were less likely than male programmers to have their pull requests accepted. Another study in 2015 found that of open-source projects on GitHub, gender diversity was a significant positive predictor of a team's productivity, meaning that open-source teams with a more even mix of different genders tended to be more highly productive.

Libraries are using open-source software to develop information as well as library services. The purpose of open source is to provide a software that is cheaper, reliable and has better quality. The one feature that makes this software so sought after is that it is free. Libraries in particular benefit from this movement because of the resources it provides. They also promote the same ideas of learning and understanding new information through the resources of other people. Open source allows a sense of community. It is an invitation for anyone to provide information about various topics. The open-source tools even allow libraries to create web-based catalogs. According to the IT source there are various library programs that benefit from this.

Government agencies and infrastructure software — Government Agencies are utilizing open-source infrastructure software, like the Linux operating system and the Apache Web-server into software, to manage information. In 2005, a new government lobby was launched under the name National Center for Open Source Policy and Research (NCOSPR) "a non-profit organization promoting the use of open source software solutions within government IT enterprises."

Open-source movement in the military — Open-source movement has potential to help in the military. The open-source software allows anyone to make changes that will improve it. This is a form of invitation for people to put their minds together to grow a software in a cost efficient manner. The reason the military is so interested is because it is possible that this software can increase speed and flexibility. Although there are security setbacks to this idea due to the fact that anyone has access to change the software, the advantages can outweigh the disadvantages. The fact that the open-source programs can be modified quickly is crucial.
A support group was formed to test these theories. The Military Open Source Software Working Group was organized in 2009 and held over 120 military members. Their purpose was to bring together software developers and contractors from the military to discover new ideas for reuse and collaboration. Overall, open-source software in the military is an intriguing idea that has potential drawbacks but they are not enough to offset the advantages.

Open source in education — Colleges and organizations use software predominantly online to educate their students. Open-source technology is being adopted by many institutions because it can save these institutions from paying companies to provide them with these administrative software systems. One of the first major colleges to adopt an open-source system was Colorado State University in 2009 with many others following after that. Colorado State Universities system was produced by the Kuali Foundation who has become a major player in open-source administrative systems. The Kuali Foundation defines itself as a group of organizations that aims to "build and sustain open-source software for higher education, by higher education." There are many other examples of open-source instruments being used in education other than the Kuali Foundation as well.
"For educators, The Open Source Movement allowed access to software that could be used in teaching students how to apply the theories they were learning". With open networks and software, teachers are able to share lessons, lectures, and other course materials within a community. OpenTechComm is a program that is dedicated to "open access, open use, and open edits- text book or pedagogical resource that teachers of technical and professional communication courses at every level can rely on to craft free offerings to their students." As stated earlier, access to programs like this would be much more cost efficient for educational departments.

Open source in healthcare — Created in June 2009 by the nonprofit eHealthNigeria, the open-source software OpenMRS is used to document health care in Nigeria. The use of this software began in Kaduna, Nigeria to serve the purpose of public health. OpenMRS manages features such as alerting health care workers when patients show warning signs for conditions and records births and deaths daily, among other features. The success of this software is caused by its ease of use for those first being introduced to the technology, compared to more complex proprietary healthcare software available in first world countries. This software is community-developed and can be used freely by anyone, characteristic of open-source applications. So far, OpenMRS is being used in Rwanda, Mozambique, Haiti, India, China, and the Philippines. The impact of open source in healthcare is also observed by Apelon Inc, the "leading provider of terminology and data interoperability solutions". Recently, its Distributed Terminology System (Open DTS) began supporting the open-source MySQL database system. This essentially allows for open-source software to be used in healthcare, lessening the dependence on expensive proprietary healthcare software. Due to open-source software, the healthcare industry has available a free open-source solution to implement healthcare standards. Not only does open source benefit healthcare economically, but the lesser dependence on proprietary software allows for easier integration of various systems, regardless of the developer.

Microsoft — Before summer of 2008, Microsoft has generally been known as an enemy of the open-source community. The company’s anti-open-source sentiment was enforced by former CEO Steve Ballmer, who referred to Linux, a widely-used open-source software, as a "malignant cancer". Microsoft also threatened Linux that they would charge royalties for violating 235 of their patents.
In 2004, Microsoft lost a European Union court case, and lost the appeal in 2007, and their further appeal in 2012: being convicted of abusing its dominant position. Specifically they had withheld inter-operability information with the open source Samba (software) project, which can be run on many platforms and aims to "removing barriers to interoperability".
In 2008, however, Sam Ramji, the then head of open-source-software strategy in Microsoft, began working closely with Bill Gates to develop a pro-open-source attitude within the software industry as well as Microsoft itself. Ramji, before leaving the company in 2009, built Microsoft's familiarity and involvement with open source, which is evident in Microsoft's contributions of open-source code to Windows Azure, "its new-age web service for building and hosting applications on the net", among other projects. These contributions would have been previously unimaginable by Microsoft. Microsoft’s change in attitude about open source and efforts to build a stronger open-source community is evidence of the growing adoption and adaption of open source.

In 1998 the term "open-source software" (as abbreviation "OSS") was coined as alternative for "free software". There were several reasons for the proposal of a new term. On one hand a group from the free software ecosystem perceived the Free Software Foundation's attitude on propagandizing the "free software" concept as "moralising and confrontational", which was also associated with the term. In addition, the "available at no cost" ambiguity of the word "free" was seen as discouraging business adoption, as also the historical ambiguous usage of the term "free software". In a 1998 strategy session in California, "open-source software" was selected by Todd Anderson, Larry Augustin, Jon Hall, Sam Ockman, Christine Peterson, and Eric S. Raymond. Richard Stallman had not been invited. The session was arranged in reaction to Netscape's January 1998 announcement of a source code release for Navigator (as Mozilla). Those at the meeting described "open source" as a "replacement label" for free software, and the Open Source Initiative was soon-after founded by Eric Raymond and Bruce Perens to promote the term as part of "a marketing program for free software". The Open Source Definition is used by the Open Source Initiative to determine whether a software license qualifies for the organization's insignia for open source software. 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. According to the OSI, Stallman initially flirted with the idea of adopting the open source term.

Alternative terms for free software

Alternative terms for free software, such as open source, FOSS, and FLOSS, have been a controversial issue among free and open-source software users from the late 1990s onwards. These terms share almost identical licence criteria and development practices.

In the 1950s to the 1990s software culture, the "free software" concept combined the nowadays differentiated software classes of public domain software, Freeware, Shareware and FOSS and was created in academia and by hobbyists and hackers.

When the term "free software" was adopted by Richard Stallman in 1983, it was still ambiguously used to describe several kinds of software. In February 1986 Richard Stallman formally defined "free software" with the publication of The Free Software Definition in the FSF's now-discontinued GNU's Bulletin as software which can be used, modified, and redistributed with little or no restriction, his four essential software freedoms. Richard Stallman's Free Software Definition, adopted by the Free Software Foundation (FSF), defines free software as a matter of liberty, not price and is inspired by the previous public domain software ecosystem. The canonical source for the document is in the philosophy section of the GNU Project website, where it is published in many languages.

On the end of 1990s the term "open source" gained much traction in public media and acceptance in software industry in context of the dotcom bubble and the open-source software driven Web 2.0. For instance, Duke University scholar Christopher M. Kelty described the Free Software movement prior to 1998 as fragmented and ""the term Open Source, by contrast, sought to encompass them all in one movement"". The term "open source" gained brought spread as open source movement which inspired many successor movements like the Open content, Open-source hardware, Open Knowledge movements. Under the impression of the success of "Open source" several journalists reported around 2000 the earlier "Free software" term and movement and its leader Stallman as being "forgotten". In response, Stallman and his FSF objected to the term "open source software" and fought since then for the term "free software". Due to the rejection of the FSF and its leader Richard Stallman of the term open source software, the ecosystem is being divided in its terminology. For example, a 2002 European Union FOSS developer survey revealed that 32.6% of them associate themselves with OSS, 48% with free software, and only 19.4% are undecided or in between. As both terms "free software" and "open-source software" have their fans and critics in the FOSS ecosystems, also unifying terms have been proposed; these include "software libre" (or libre software), "FLOSS" (free/libre and open-source software), and "FOSS" (or F/OSS, free and open-source software).

The first known use of the phrase "free open-source software" (in short FOSS or seldom F/OSS) on Usenet was in a posting on March 18, 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 European Union's institutions later also used the FOSS term while before using FLOSS, as also scholar in publications.

While probably used earlier (as early as the 1990s) "Software libre" got broader public reception when in 2000 the European Commission adopted it. The word "libre", borrowed from the Spanish and French languages, means having liberty. This avoids the freedom-cost ambiguity of the English word "free".

FLOSS was used in 2001 as a project acronym by Rishab Aiyer Ghosh for "free/libre and 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, for example the "F" representing "free" (English) or "frei" (German), and the "L" representing "libre" (Spanish or French), "livre" (Portuguese), or "libero" (Italian), 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 English's "free".

By the end of 2004, the FLOSS acronym had been used in official English documents issued by South Africa, Spain, and Brazil. Other scholars and institutions use it too.

Richard Stallman endorses the term FLOSS to refer to "open-source" and "free software" without necessarily choosing between the two camps, however, he asks people to consider supporting the "free/libre software" camp. Stallman has suggested that the term "unfettered software" would be an appropriate, non-ambiguous replacement, but that he would not push for it because there was too much momentum and too much effort behind the term "free software".

The term "FLOSS" has come under some criticism for being counterproductive and sounding silly. For instance, Eric Raymond, co-founder of the Open Source Initiative, has stated in 2009:

"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."
None of these terms, or the term "free software" itself, have been trademarked. Bruce Perens of OSI attempted to register "open source" as a service mark for OSI in the United States of America, but that attempt failed to meet the relevant trademark standards of specificity. OSI claims a trademark on "OSI Certified", and applied for trademark registration, but did not complete the paperwork. The United States Patent and Trademark Office labels it as "abandoned".

While the term "free software" is associated with FSF's definition, and the term "open-source software" is associated with OSI's definition, the other terms have not been claimed by any group in particular. While the FSF's and OSI's definitions are worded quite differently the set of software that they cover is almost identical.

All of the terms are used interchangeably, the choice of which to use is mostly political (wanting to support a certain group) or practical (thinking that one term is the clearest).

The primary difference between free software and open source is one of philosophy. According to the Free Software Foundation, "Nearly all open source software is free software. The two terms describe almost the same category of software, but they stand for views based on fundamentally different values."

The choice of term has little or no impact on which licences are valid or used by the different camps, while recommendations might vary. At least until the release of the GPLv3, the usage of the GPLv2 united the Open source and free software camp. The vast majority of software referred to by all these terms is distributed under a small set of licences, all of which are unambiguously accepted by the various de facto and de jure guardians of each of these terms. The majority of the software is either one of few permissive software licenses (the BSD licenses, the MIT License, and the Apache License) or one of few copyleft licenses (the GNU General Public License v2, GPLv3, the GNU Lesser General Public License, or the Mozilla Public License).

The Free Software Foundation (List of FSF approved software licences) and the Open Source Initiative (List of OSI approved software licences) each publish lists of licences that they accept as complying with their definitions of free software and open-source software respectively. The Open Source Initiative considers almost all free software licenses to also be open source and way around. These include the latest versions of the FSF's three main licenses, the GPLv3, the Lesser General Public License (LGPL), and the GNU Affero General Public License (AGPL).

Apart from these two organisations, many more FOSS organizations publish recommendations and comments on licenses and licensing matters. The Debian project is seen by some to provide useful advice on whether particular licences comply with their Debian Free Software Guidelines. Debian does not publish a list of "approved" licences, but its judgments can be tracked by checking what licences are used by software they have allowed into their distribution. In addition, the Fedora Project does provide a list of approved licences (for Fedora) based on approval of the Free Software Foundation (FSF), the Open Source Initiative (OSI), and consultation with Red Hat Legal. It exist also the copyfree movement, the BSDs as also the Apache and Mozilla Foundation with own points of views on licenses.

There is also a class of software that is covered by the names discussed in this article, but which doesn't have a licence: software for which the source code is in the public domain. The use of such source code, and therefore the executable version, is not restricted by copyright and therefore does not need a free software licence to make it free software. However, not all countries have the same form of "public domain" regime and possibilities of dedicating works and the authors rights in the public domain.

Further, for distributors to be sure that software is released into the public domain, the usually need to see something written to confirm this. Thus even without a licence, a written note about lack of copyright and other exclusive rights often still exists (a waiver or anti-copyright notice), which can be seen as license substitute. There are also mixed forms between waiver and license, for instance the public domain like licenses CC0 and the Unlicense, with an all permissive license as fallback in case of ineffectiveness of the waiver.

The free software community in some parts of India sometimes uses the term "Swatantra software" since the term "Swatantra" means free in Sanskrit, which is the ancestor of all Indo-European Languages of India, including Hindi, despite English being the lingua franca. Other terms such as "kattatra menporul (கட்டற்ற_மென்பொருள்)" for free software, where kattatra means free and menporul means software is also being used in Tamil Nadu and Tamils in other parts of the world. In The Philippines, "malayang software" is sometimes used. The word "libre" exists in the Filipino language, and it came from the Spanish language, but has acquired the same cost/freedom ambiguity of the English word "free". According to Meranau "Free" is "KANDURI", Diccubayadan, Libre.

Despite initially accepting it, Richard Stallman of the FSF now flatly opposes the term "Open Source" being applied to what they refer to as "free software". Although he agrees that the two terms describe "almost the same category of software", Stallman considers equating the terms incorrect and misleading. Stallman also opposes the professed pragmatism of the Open Source Initiative, as he fears that the free software ideals of freedom and community are threatened by compromising on the FSF's idealistic standards for software freedom. The FSF considers free software to be a subset of open-source software, and Richard Stallman explained that DRM software, for example, can be developed as open source, despite that it does not give its users freedom (it restricts them), and thus doesn't qualify as free software.

Open-source software

Open-source software (OSS) is a type of computer software in which source code is released under a license in which the copyright holder grants users the rights to study, change, and distribute the software to anyone and for any purpose. Open-source software may be developed in a collaborative public manner. According to scientists who have studied it, open-source software is a prominent example of open collaboration. The term is often written without a hyphen as "open source software".

Open-source software development, or collaborative development between multiple independent contributors, generates an increasingly more diverse scope of design perspective than any company is capable of developing and sustaining long term. A 2008 report by the Standish Group states that adoption of open-source software models has resulted in savings of about $60 billion (£48 billion) per year to consumers.

In the early days of computing, programmers and developers shared software in order to learn from each other and evolve the field of computing. Eventually, the open-source notion moved to the way side of commercialization of software in the years 1970-1980. However, academics still often developed software collaboratively. For example Donald Knuth in 1979 with the TeX typesetting system or Richard Stallman in 1983 with the GNU operating system. 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 source code subsequently became the basis behind SeaMonkey, Mozilla Firefox, Thunderbird and KompoZer.

Netscape's act prompted Raymond and others to look into how to bring the Free Software Foundation's free software ideas and perceived 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 sharing and collaborating on software source code. The new term they chose was "open source", which was soon adopted by Bruce Perens, publisher Tim O'Reilly, Linus Torvalds, and others. 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, commercial software vendors 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." However, while Free and open-source software 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. IBM, Oracle, Google and State Farm are just a few of the companies with a serious public stake in today's competitive open-source market. There has been a significant shift in the corporate philosophy concerning the development of FOSS.

The free-software movement was launched in 1983. In 1998, a group of individuals advocated that the term free software should be replaced by open-source software (OSS) as an expression which is less ambiguous and more comfortable for the corporate world. Software developers may want to publish their software with an open-source license, so that anybody may also develop the same software or understand its internal functioning. With open-source software, generally anyone is allowed to create modifications of it, port it to new operating systems and instruction set architectures, share it with others or, in some cases, market it. Scholars Casson and Ryan have pointed out several policy-based reasons for adoption of open source – in particular, the heightened value proposition from open source (when compared to most proprietary formats) in the following categories:

The "Open Source Definition" presents an open-source philosophy and further defines the terms of use, modification and redistribution of open-source software. Software licenses grant rights to users which would otherwise be reserved by copyright law to the copyright holder. Several open-source software licenses have qualified within the boundaries of the "Open Source Definition". The most prominent and popular example is the GNU General Public License (GPL), which "allows free distribution under the condition that further developments and applications are put under the same licence", thus also free.

The "open source" label came out of a strategy session held on April 7, 1998 in Palo Alto in reaction to Netscape's January 1998 announcement of a source code release for Navigator (as Mozilla). A group of individuals at the session included Tim O'Reilly, Linus Torvalds, Tom Paquin, Jamie Zawinski, Larry Wall, Brian Behlendorf, Sameer Parekh, Eric Allman, Greg Olson, Paul Vixie, John Ousterhout, Guido van Rossum, Philip Zimmermann, John Gilmore and Eric S. Raymond. They used the opportunity before the release of Navigator's source code to clarify a potential confusion caused by the ambiguity of the word "free" in English.

Many people claimed that the birth of the Internet, since 1969, started the open-source movement, while others do not distinguish between open-source and free software movements.

The Free Software Foundation (FSF), started in 1985, intended the word "free" to mean "freedom to distribute" (or "free as in free speech") and not "freedom from cost" (or "free as in free beer"). Since a great deal of free software already was (and still is) free of charge, such free software became associated with zero cost, which seemed anti-commercial.

The Open Source Initiative (OSI) was formed in February 1998 by Eric Raymond and Bruce Perens. With at least 20 years of evidence from case histories of closed software development versus open development already provided by the Internet developer community, the OSI presented the "open source" case to commercial businesses, like Netscape. The OSI hoped that the use of the label "open source", a term suggested by Christine Peterson of the Foresight Institute at the strategy session, would eliminate ambiguity, particularly for individuals who perceive "free software" as anti-commercial. They sought to bring a higher profile to the practical benefits of freely available source code, and they wanted to bring major software businesses and other high-tech industries into open source. Perens attempted to register "open source" as a service mark for the OSI, but that attempt was impractical by trademark standards. Meanwhile, due to the presentation of Raymond's paper to the upper management at Netscape—Raymond only discovered when he read the press release, and was called by Netscape CEO Jim Barksdale's PA later in the day—Netscape released its Navigator source code as open source, with favorable results.

The Open Source Initiative's (OSI) definition is recognized by several governments internationally as the standard or "de facto" definition. In addition, many of the world's largest open-source-software projects and contributors, including Debian, Drupal Association, FreeBSD Foundation, Linux Foundation, Mozilla Foundation, Wikimedia Foundation, Wordpress Foundation have committed to upholding the OSI's mission and Open Source Definition through the OSI Affiliate Agreement.

OSI uses "The Open Source Definition" to determine whether it considers a software license open source. The definition was based on the Debian Free Software Guidelines, written and adapted primarily by Perens. Perens did not base his writing on the "four freedoms" from the Free Software Foundation (FSF), which were only widely available later.

Under Perens' definition, "open source" is a broad software license that makes source code available to the general public with relaxed or non-existent restrictions on the use and modification of the code. It is an explicit "feature" of open source that it puts very few restrictions on the use or distribution by any organization or user, in order to enable the rapid evolution of the software.

When an author contributes code to an open-source project (e.g., Apache.org) they do so under an explicit license (e.g., the Apache Contributor License Agreement) or an implicit license (e.g. the open-source license under which the project is already licensing code). Some open-source projects do not take contributed code under a license, but actually require joint assignment of the author's copyright in order to accept code contributions into the project.

Examples of free software license / open-source licenses include Apache License, BSD license, GNU General Public License, GNU Lesser General Public License, MIT License, Eclipse Public License and Mozilla Public License.

The proliferation of open-source licenses is a negative aspect of the open-source movement because it is often difficult to understand the legal implications of the differences between licenses. With more than 180,000 open-source projects available and more than 1400 unique licenses, the complexity of deciding how to manage open-source use within "closed-source" commercial enterprises has dramatically increased. Some are home-grown, while others are modeled after mainstream FOSS licenses such as Berkeley Software Distribution ("BSD"), Apache, MIT-style (Massachusetts Institute of Technology), or GNU General Public License ("GPL"). In view of this, open-source practitioners are starting to use classification schemes in which FOSS licenses are grouped (typically based on the existence and obligations imposed by the copyleft provision; the strength of the copyleft provision).

An important legal milestone for the open source / free software movement was passed in 2008, when the US federal appeals court ruled that free software licenses definitely do set legally binding conditions on the use of copyrighted work, and they are therefore enforceable under existing copyright law. As a result, if end-users violate the licensing conditions, their license disappears, meaning they are infringing copyright.
Despite this licensing risk, most commercial software vendors are using open source software in commercial products while fulfilling the license terms, e.g. leveraging the Apache license.

Certification can help to build user confidence. Certification could be applied to the simplest component, to a whole software system. The United Nations University International Institute for Software Technology, initiated a project known as "The Global Desktop Project". This project aims to build a desktop interface that every end-user is able to understand and interact with, thus crossing the language and cultural barriers. The project would improve developing nations' access to information systems. UNU/IIST hopes to achieve this without any compromise in the quality of the software by introducing certifications.

In his 1997 essay "The Cathedral and the Bazaar", open-source evangelist Eric S. Raymond suggests a model for developing OSS known as the "bazaar" model. Raymond likens the development of software by traditional methodologies to building a cathedral, "carefully crafted by individual wizards or small bands of mages working in splendid isolation". He suggests that all software should be developed using the bazaar style, which he described as "a great babbling bazaar of differing agendas and approaches."

In the traditional model of development, which he called the "cathedral" model, development takes place in a centralized way. Roles are clearly defined. Roles include people dedicated to designing (the architects), people responsible for managing the project, and people responsible for implementation. Traditional software engineering follows the cathedral model.

The bazaar model, however, is different. In this model, roles are not clearly defined. Gregorio Robles suggests that software developed using the bazaar model should exhibit the following patterns:Data suggests, however, that OSS is not quite as democratic as the bazaar model suggests. An analysis of five billion bytes of free/open source code by 31,999 developers shows that 74% of the code was written by the most active 10% of authors. The average number of authors involved in a project was 5.1, with the median at 2.

Open source software is usually easier to obtain than proprietary software, often resulting in increased use. Additionally, the availability of an open source implementation of a standard can increase adoption of that standard. It has also helped to build developer loyalty as developers feel empowered and have a sense of ownership of the end product.

Moreover, lower costs of marketing and logistical services are needed for OSS. OSS also helps companies keep abreast of technology developments. It is a good tool to promote a company's image, including its commercial products. The OSS development approach has helped produce reliable, high quality software quickly and inexpensively.

Open source development offers the potential for a more flexible technology and quicker innovation. It is said to be more reliable since it typically has thousands of independent programmers testing and fixing bugs of the software. Open source is not dependent on the company or author that originally created it. Even if the company fails, the code continues to exist and be developed by its users. Also, it uses open standards accessible to everyone; thus, it does not have the problem of incompatible formats that exist in proprietary software.

It is flexible because modular systems allow programmers to build custom interfaces, or add new abilities to it and it is innovative since open source programs are the product of collaboration among a large number of different programmers. The mix of divergent perspectives, corporate objectives, and personal goals speeds up innovation.

Moreover, free software can be developed in accord with purely technical requirements. It does not require thinking about commercial pressure that often degrades the quality of the software. Commercial pressures make traditional software developers pay more attention to customers' requirements than to security requirements, since such features are somewhat invisible to the customer.

It is sometimes said that the open source development process may not be well defined and the stages in the development process, such as system testing and documentation may be ignored. However this is only true for small (mostly single programmer) projects. Larger, successful projects do define and enforce at least some rules as they need them to make the teamwork possible. In the most complex projects these rules may be as strict as reviewing even minor change by two independent developers.

Not all OSS initiatives have been successful, for example SourceXchange and Eazel. Software experts and researchers who are not convinced by open source's ability to produce quality systems identify the unclear process, the late defect discovery and the lack of any empirical evidence as the most important problems (collected data concerning productivity and quality). It is also difficult to design a commercially sound business model around the open source paradigm. Consequently, only technical requirements may be satisfied and not the ones of the market. In terms of security, open source may allow hackers to know about the weaknesses or loopholes of the software more easily than closed-source software. It depends on control mechanisms in order to create effective performance of autonomous agents who participate in virtual organizations.

In OSS development, tools are used to support the development of the product and the development process itself.

Revision control systems such as Concurrent Versions System (CVS) and later Subversion (SVN) and Git are examples of tools, often themselves open source, help manage the source code files and the changes to those files for a software project. The projects are frequently hosted and published on source-code-hosting facilities such as Launchpad.

Open source projects are often loosely organized with "little formalised process modelling or support", but utilities such as issue trackers are often used to organize open source software development. Commonly used bugtrackers include Bugzilla and Redmine.

Tools such as mailing lists and IRC provide means of coordination among developers. Centralized code hosting sites also have social features that allow developers to communicate.

Some of the "more prominent organizations" involved in OSS development include the Apache Software Foundation, creators of the Apache web server; the Linux Foundation, a nonprofit which employed Linus Torvalds, the creator of the Linux operating system kernel; the Eclipse Foundation, home of the Eclipse software development platform; the Debian Project, creators of the influential Debian GNU/Linux distribution; the Mozilla Foundation, home of the Firefox web browser; and OW2, European-born community developing open source middleware. New organizations tend to have a more sophisticated governance model and their membership is often formed by legal entity members.

Open Source Software Institute is a membership-based, non-profit (501 (c)(6)) organization established in 2001 that promotes the development and implementation of open source software solutions within US Federal, state and local government agencies. OSSI's efforts have focused on promoting adoption of open source software programs and policies within Federal Government and Defense and Homeland Security communities.

Open Source for America is a group created to raise awareness in the United States Federal Government about the benefits of open source software. Their stated goals are to encourage the government's use of open source software, participation in open source software projects, and incorporation of open source community dynamics to increase government transparency.

Mil-OSS is a group dedicated to the advancement of OSS use and creation in the military.

The debate over "open source" vs. "closed source" (alternatively called proprietary software) is sometimes heated.

The top four reasons (as provided by Open Source Business Conference survey) individuals or organizations choose open source software are:

Since innovative companies no longer rely heavily on software sales, proprietary software has become less of a necessity. As such, things like open source content management system—or CMS—deployments are becoming more commonplace. In 2009, the US White House switched its CMS system from a proprietary system to Drupal open source CMS. Further, companies like Novell (who traditionally sold software the old-fashioned way) continually debate the benefits of switching to open source availability, having already switched part of the product offering to open source code. In this way, open source software provides solutions to unique or specific problems. As such, it is reported that 98% of enterprise-level companies use open source software offerings in some capacity.

With this market shift, more critical systems are beginning to rely on open source offerings, allowing greater funding (such as US Department of Homeland Security grants) to help "hunt for security bugs." According to a pilot study of organizations adopting (or not adopting) OSS, the following factors of statistical significance were observed in the manager's beliefs: (a) attitudes toward outcomes, (b) the influences and behaviors of others, and (c) their ability to act.

Proprietary source distributors have started to develop and contribute to the open source community due to the market share shift, doing so by the need to reinvent their models in order to remain competitive.

Many advocates argue that open source software is inherently safer because any person can view, edit, and change code. A study of the Linux source code has 0.17 bugs per 1000 lines of code while proprietary software generally scores 20–30 bugs per 1000 lines.

According to the Free software movement's leader, Richard Stallman, the main difference is that by choosing one term over the other (i.e. either "open source" or "free software") one lets others know about what one's goals are: "Open source is a development methodology; free software is a social movement." Nevertheless, there is significant overlap between open source software and free software.

The FSF said that the term "open source" fosters an ambiguity of a different kind such that it confuses the mere availability of the source with the freedom to use, modify, and redistribute it. On the other hand, the "free software" term was criticized for the ambiguity of the word "free" as "available at no cost", which was seen as discouraging for business adoption, and for the historical ambiguous usage of the term.

Developers have used the alternative terms "Free and Open Source Software" (FOSS), or "Free/Libre and Open Source Software" (FLOSS), consequently, to describe open source software that is also free software. While the definition of open source software is very similar to the FSF's free software definition it was based on the Debian Free Software Guidelines, written and adapted primarily by Bruce Perens with input from Eric S. Raymond and others.

The term "open source" was originally intended to be trademarkable; however, the term was deemed too descriptive, so no trademark exists. The OSI would prefer that people treat open source as if it were a trademark, and use it only to describe software licensed under an OSI approved license.

OSI Certified is a trademark licensed only to people who are distributing software licensed under a license listed on the Open Source Initiative's list.

Although the OSI definition of "open source software" is widely accepted, a small number of people and organizations use the term to refer to software where the source is available for viewing, but which may not legally be modified or redistributed. Such software is more often referred to as "source-available", or as "shared source", a term coined by Microsoft in 2001. While in 2007 two of Microsoft's Shared Source Initiative licenses were certified by the OSI, most licenses from the SSI program are still "source-available only".

Open-sourcing is the act of propagating the open source movement, most often referring to releasing previously proprietary software under an open source/free software license, but it may also refer programming Open Source software or installing Open Source software.

Notable software packages, previously proprietary, which have been open sourced include:
Before changing the license of software, distributors usually audit the source code for third party licensed code which they would have to remove or obtain permission for its relicense. Backdoors and other malware should also be removed as they may easily be discovered after release of the code.

Open source software projects are built and maintained by a network of volunteer programmers and are widely used in free as well as commercial products. Prime examples of open-source products are the Apache HTTP Server, the e-commerce platform osCommerce, internet browsers Mozilla Firefox and Chromium (the project where the vast majority of development of the freeware Google Chrome is done) and the full office suite LibreOffice. One of the most successful open-source products is the GNU/Linux operating system, an open-source Unix-like operating system, and its derivative Android, an operating system for mobile devices. In some industries, open source software is the norm.

While the term "open source" applied originally only to the source code of software, it is now being applied to many other areas such as Open source ecology, a movement to decentralize technologies so that any human can use them. However, it is often misapplied to other areas which have different and competing principles, which overlap only partially.

The same principles that underlie open source software can be found in many other ventures, such as open-source hardware, Wikipedia, and open-access publishing. Collectively, these principles are known as open source, open content, and open collaboration: "any system of innovation or production that relies on goal-oriented yet loosely coordinated participants, who interact to create a product (or service) of economic value, which they make available to contributors and non-contributors alike."

This "culture" or ideology takes the view that the principles apply more generally to facilitate concurrent input of different agendas, approaches and priorities, in contrast with more centralized models of development such as those typically used in commercial companies.