Open source is a set of principles and practices on how to write software, the most important of which is that the source code is openly available. The Open Source Definition, which was created by Bruce Perens[1] and Eric Raymond and is currently maintained by the Open Source Initiative, adds additional meaning to the term: one should not only get the source code but also have the right to use it. If the latter is denied the license is categorized as a shared source license.
The Open Source Definition is used by the Open Source Initiative to determine whether or not a software license can be considered open source. The definition was based on the Debian Free Software Guidelines, written and adapted primarily by Bruce Perens[2].
Under The Open Source Definition, licenses must meet ten conditions in order to be considered open source licenses. Below is a copy of the definition, with unauthorized explanatory additions. There is a link to the original unmodified text below. It was taken under/for fair use.
Richard Stallman originally accepted Debian's document as a good definition of Free Software, but later created the Free software definition - in part to differentiate Free Software from Open Source. [3] In practice, licenses which meet the open source definition almost always also meet the Free software definition and vice-versa.[4]
While the term applied originally only to the source code of software,[5] 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.
Opponents of the spread of the label “open source,” including Richard Stallman, argue that the requirements and restrictions ensure the continuation of the effort, and resist attempts to redefine the labels. He argues also that most supporters of open source are actually supporters of much more equitable agreements and support re-integration of derived works and that most contributors do not intend to release their work to others who can extend it, hide the extensions, patent those very extensions, and demand royalties or restrict the use of all other users - all while not violating the open source principles with respect to the initial code they acquired.
See The Open Source Definition for the exact operational definition and examples of licenses that satisfy, and do not satisfy, those principles.
Under Perens' definition, open source describes a broad general type of software license that makes source code available to the general public with relaxed or non-existent copyright restrictions. The principles, as stated, say absolutely nothing about trademark or patent use and require absolutely no cooperation to ensure that any common audit or release regime applies to any derived works. It is an explicit “feature” of open source that it may put no restrictions on the use or distribution by any organization or user.
It forbids this, in principle, to guarantee continued access to derived works even by the major original contributors. In contrast to free software or open content licenses, which are often confused with open source but have much more rigorous rules and conventions, open source deliberately errs in favor of allowing any use by any party whatsoever, and offers few or no means or recourses to prevent a free rider problem or deal with proliferation of bad copies that misled end users.
Perhaps because of this flexibility, which facilitates large commercial users and vendors, the most successful applications of open source have been in consortium. These use other means such as trademarks to control bad copies and require specific performance guarantees from consortium members to assure re-integration of improvements. Accordingly they do not need potentially conflicting clauses in licenses.
The loose definition has led to a proliferation of licenses that can claim to be open source but which would not satisfy the share alike provision that free software and open content licenses require. A very common license, the Creative Commons CC-by-nc-sa, requires a commercial user to acquire a separate license for-profit use. This is explicitly against the open source principles, as it discriminates against a type of use or user. However, the requirement imposed by free software to reliably redistribute derived works, does not violate these principles. Accordingly, free software and consortium licenses are a type of open source, but open content isn't insofar as it allows such restrictions.
The principles of open source have been adapted for many other forms of user generated content. Supporters of the open content movement advocate some restrictions of use, requirements to share changes, and attribution to other authors of the work.
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.[6]
Advocates of the open source principles often point to Wikipedia as an example, but Wikipedia has in fact often restricted certain types of use or user, and the GFDL license it uses makes specific requirements of all users that technically violate the open source principles.
See main article: Open Source history.
Very similar to open standards, researchers with access to the Advanced Research Projects Agency Network (ARPANET) used a process called Request for Comments to develop telecommunication network protocols. Characterized by contemporary open source work, this 1960's collaborative process led to the birth of the Internet in 1969. There are earlier instances of open source movements and free software such as IBM's source releases of its operating systems in the 1960s and the SHARE user group that formed to facilitate the exchange of such software.
The decision by some people in the free software movement to use the label “open source” came out of a strategy session[7] held at Palo Alto, California, in reaction to Netscape's January 1998 announcement of a source code release for Navigator. The group of individuals at the session included Christine Peterson who suggested “open source”, Todd Anderson, Larry Augustin, Jon Hall, Sam Ockman, Michael Tiemann and Eric S. Raymond. They 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. Netscape licensed and released its code as open source under the Netscape Public License and subsequently under the Mozilla Public License.[8]
The term “open source” has been used previously (as early as 1987) with a much wider definition[9][10] and is still used in that wider meaning by many people who do not necessarily accept the Open Source Initiative's more limited definition of the term.
The term was given a big boost at an event organized in April 1998 by technology publisher Tim O'Reilly. Originally titled the “Freeware Summit” and later known as the “Open Source Summit”,[11] the event brought together the leaders of many of the most important free and open source projects, including Linus Torvalds, Larry Wall, Brian Behlendorf, Eric Allman, Guido van Rossum, Michael Tiemann, Paul Vixie, Jamie Zawinski of Netscape, and Eric Raymond. At that meeting, the confusion caused by the name “free software” was brought up. Tiemann argued for “sourceware” as a new term, while Raymond argued for “open source.” The assembled developers took a vote, and the winner was announced at a press conference that evening. Five days later, Raymond made the first public call to the free software community to adopt the new term. The Open Source Initiative was formed shortly thereafter.[12]
The Open Source Initiative (OSI) formed in February 1998 by Raymond and Perens. With about 20 years of evidence from case histories of closed and open development already provided by the Internet, the OSI continued to present the 'open source' case to commercial businesses. They sought to bring a higher profile to the practical benefits of freely available source code, and wanted to bring major software businesses and other high-tech industries into open source. Perens adapted Debian's Free Software Guidelines to make the The Open Source Definition.[13]
Open source software (OSS) are built and maintained by a large network of volunteer programmers. Prime examples of open source products are the web-server “Apache”, the internet address system “Internet Protocol”, and the internet browser “Mozilla Firefox”. Yet, one of the most successful programs is the “Linux” operating system, the open source software variant of the UNIX operating system[14][15]
The criticisms of the specific OSI principles are dealt with above as part of the definition and differentiation from other terms. The open content movement does not recognize nor endorse the OSI principles and embraces instead mutual share-alike agreements that require derived works to be re-integrated and treated equitably, e.g. not patented or trademarked to the detriment of the individual contributors/creators.
Another criticism of the Open Source movement is that these projects are not really as self-organizing as their proponents claim. This argument holds that Open Source projects succeed only when they have a strong central manager, even if that manager is a volunteer. The article Open Source Projects Manage Themselves? Dream On. by Chuck Connell explains this viewpoint. Eric Raymond responded to this criticism, and Chuck Connell answered.
The legal and cultural criticisms are both addressed as part of a common set of objections and criticisms by those who prefer share-alike as an organizing principle. This includes Creative Commons which simply ignores the OSI principles and endorses licenses that clearly violate them such as CC-by-nc-sa.
Of the vocal critics Richard Stallman of the Free Software Foundation (FSF)—whose GFDL license is used by Wikipedia itself, flatly opposes the term “Open Source” being applied to what they refer to as “free software”. Although it's clear that legally free software does qualify as open source, he considers that the category is abusive. [16] They also oppose the professed pragmatism of the Open Source Initiative, as they fear that the free software ideals of freedom and community are threatened by compromising on the FSF's idealistic standards for software freedom.[17][18]
Software experts and researchers on open source software (OSS) have identified several advantages and disadvantages. The main advantage for business is that open source is a good way for business to achieve greater penetration of the market. Companies that offer open source software are able to establish an industry standard and, thus, gain competitive advantage. It has also helped build developer loyalty as developers feel empowered and have a sense of ownership of the end product[19]. Moreover less costs of marketing and logistical services are needed for OSS. It also helps companies to keep abreast of all technology developments. It is a good tool to promote a companies’ image, including its commercial products[20]. The OSS development approach has helped produce reliable, high quality software quickly and inexpensively. Besides, it 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. It is flexible because modular systems allow programmers to build custom interfaces, or ad 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[21]. Moreover free software can be developed in accord with purely technical requirements it does not require to think about commercial pressure that often degrade the quality of the software. Commercial pressures make traditional software developer pay more attention to customers requirements than to security requirements, since such features are somewhat invisible to the customer[22].
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 team work possible (see examples http://www.gnu.org/software/classpath/docs/hacking.html, http://jgap.sourceforge.net/doc/codestyle.html). In the most complex projects these these rules may be as strict as reviewing even minor change by two independent developers http://www.javalobby.org/java/forums/t98834.html.
Not all OSS initiatives have been successful, for example, SourceXchange and Eazel[23]. 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)[24]. 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[25]. 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 is depended of control mechanisms in order to create effective performance of autonomous agents who participate in virtual organizations[26].
There are a number of commonly recognized barriers to the adoption of open source software by enterprises. These barriers include the perception that open source licenses are viral, lack of formal support and training, the velocity of change, and a lack of a long term roadmap. The majority of these barriers are risk-related. From the other side, not all proprietary projects disclose exact future plans, not all open source licenses are equally viral and many serious OSS projects (especially operating systems) actually make money from paid support and documentation.
Many business models exist around open source software to provide a 'whole product' to help reduce these risks. The 'whole product' typically includes support, commercial licenses, professional services, training, certification, partner programs, references and use cases. These business models range from 'services only' organizations that do not participate in the development of the software to models where the majority of the software is created by full-time committers that are employed by a central organization. These business models have come into existence recently and their operation is not commonly understood. One model that has been developed to explain this is the Bee Keeper Model