Note: "open source" in the intelligence community simply means "any information accessible to the public, possibly after paying a fee." This article is about open source software, a more common meaning for the term "open source."

Open source or open-source software (OSS) is any computer software distributed under an open-source license or available under terms meeting the Open Source Definition. When used as an adjective, the term is hyphenated, e.g. "Apache is open-source software"; used as a noun, there is no hyphen.

Contents

1 Overview 2 The open source movement 3 The open-source debate 4 Security 5 Open source advocates 6 Projects and organizations 7 Examples of open-source licenses 8 Examples of open-source software 9 Related topics 10 See also 10.1 Contrast with 11 External links 11.1 On the creation of the name "Open Source" 11.2 General links about open source

Overview

Open-source software is required to have its source code freely available; end-users have the right to modify and redistribute the software, as well as the right to package and sell the software. Software with source code in the public domain meets these criteria, as does any software distributed under the popular GNU General Public License (GPL). Open-source licenses may have additional restrictions, such as a requirement to preserve the authors' names and copyright statement in the code.

The term open source in common usage may refer to any software with publicly available source code, though this usage is discouraged by many. Examples of such non-OSF open source software include some versions of Solaris and PGP. There are also shared source licenses which have some similarities with open source, but a number of critical differences make such licenses incompatible with the Open Source Definition.

Despite apparent similarities, open-source software is distinct from free software. The Free Software Foundation's (FSF) free software definition is more restrictive than the Open Source Definition; as a consequence of this, free software is open source, but open-source software may or may not be "free". In practice, nearly all open-source licenses also satisfy the FSF's free software definition, and the difference is more a matter of philosophical emphasis. (One exception is an early version of the Apple Public Source License, which was considered open-source but not free, because it did not allow private modified versions; this restriction was later removed.) Software distributed under both the GPL and BSD licenses is considered both free and open-source.

The decision to adopt the term "open source", suggested by Christine Peterson of the Foresight Institute, was based partly on the confusion caused by the dual meaning of the word "free"; the FSF intended the word to mean "free as in free speech", not "free as in free beer", but nevertheless, free software came to be associated with zero cost, a problem which was exacerbated by the fact that a great deal of it is, in fact, free of charge. It was hoped that the usage of the newer term "open source" would eliminate such ambiguity, particularly for users who might mistakenly associate "free software" with anti-commercialism. Since its introduction, however, the "open source" label has been criticized for fostering an ambiguity of a different kind: that of confusing it for mere availability of the source, rather than the freedom to use, modify, and redistribute it.

For additional comparison, see open source movement and free software movement.

The open source movement

The open source movement is a large movement of programmers and other computer users that advocates unrestricted access to the source code of software. It grew out of licenses such as BSD, the ubiquitous access to Unix source code at universities and goals which differ somewhat from those of the Free software movement. The line between the two is somewhat blurry; both are founded in the hacker culture. Mostly, the Free software movement is based upon political and philosophical ideals, while open source proponents tend to focus on more pragmatic arguments. Openness is a term that has evolved now to refer to projects that are open to anyone and everyone to contribute to, before and/or after the actual programming. Both groups assert that this more open style of licensing allows for a superior software development process, and therefore that pursuing it is in line with rational self-interest. Free software advocates, however, would argue that "freedom" is a paramount merit that one should prefer (or at least weigh heavily) even in cases where proprietary software has some superior technical features.

Proponents of the open source development methodology claim that it is superior in a number of ways to the closed source method (and some individuals may suggest that the open source methodology is the methodology that is able to produce the quality of software that can be higher than that produced by any other methodology or technique). Stability, reliability, and security are frequently cited as reasons to support open source. One successful application of the open source model is the Linux operating system, which is renowned for its stability and security characteristics. Among the works that explore and justify open source development is a series of works by Eric S. Raymond which includes The Cathedral and the Bazaar and Homesteading the Noosphere.

Open source advocates point out that as of the early 2000s, at least 90 percent of computer programmers are employed not to produce software for direct sale, but rather to design and customize software for other purposes, such as in-house applications. According to advocates, this statistic implies that the value of software lies primarily in its usefulness to the developer or developing organization, rather than in its potential sale value, and that consequently there is usually no compelling economic reason to keep source code secret from competitors. Open-source advocates further argue that corporations frequently over-protect software in ways actually damaging to their own interests, for reasons ranging from mere institutional habit through reflexive territoriality to a rational but incorrect evaluation of the tradeoffs between collecting secrecy rent and the quality and market payoff of openness.

The open-source debate

The debate over open source vs. closed source (alternatively called proprietary development) is heated at times. The most obvious complaint against open-source software involves the complaint that making money through some traditional methods, such as the sale of the use of individual copies and patent royalty payments, is much more difficult and sometimes impractical with open-source software. Some software development companies sell the rights to use individual copies of software as their primary source of income, using a combination of copyright, patent, trademark, and trade secret laws (collectively called intellectual property rights laws). By keeping their software source code hidden, they can make it impractical to make changes to a program they develop, and demand fees for its use and improvement. While most software is written for internal use, the fees from sale and license of commercial software are the primary source of income for companies which do sell software. Additionally, some companies with large research and development teams develop extensive patent portfolios, again with the purpose of making money from patent royalties. These companies can charge licensing fees for the use of their patents in software, however open source distribution creates the potential for an infinite number of derived works using the patented technology with no payment to the patent holder.

This complaint is countered by a large number of alternative funding streams, which are actually better-connected to the real costs of creating and maintaining software. After all, the cost of making a copy of a software program is essentially zero, so per-use fees may make sense for physical products but are not reasonable for software programs. At one time, open-source software development was almost entirely volunteer-driven, and this is still true for many small projects. However, a large number of alternative funding streams have been identified and employed for open source software:

• give away the program and charge for installation and support (this is the model used by many Linux distributions).
• "commoditize complements", that is, intentionally make one product cheaper so that the user is more likely to purchase a product or service you do sell (this is a primary reason for OpenOffice.org; Sun gives away the office suite to encourage users to buy their computer hardware).
• cost avoidance / cost sharing; many developers need the product, so they share the cost of its development (this is the genesis of the X Window system and Apache).

Increasingly open-source software is developed by commercial organizations. In 2004, Andrew Morton noted that 37,000 of the 38,000 recent patches in the Linux kernel were created by developers directly paid to develop the Linux kernel. Many projects, such as the X Window system and Apache, have had commercial development as a primary source of improvements since their inception, and this trend has accelerated over time.

One argument made against open-source software is that closed-source development allows more control over the final product, though this argument does not do much to support its assertion. The theory behind this argument is that open-source software is primarily a volunteer effort, while closed-source development is typically a salary-driven effort. By having the monetary resources to fund developers and management, and the ability to control development in a given direction, closed-source proponents argue that development can be more efficient and more focused. But this argument misses many key points. First, it is no longer true that OSS is necessarily a volunteer effort; increasingly this is actually not true. Also, a project can be primarily in-house or not, independent of whether or not it's open source. If a project is developed entirely externally to an organization, without any support, then of course that project need not take that organization's needs seriously. However, an organization can devote increasing amounts of resources to ensure its needs are met. At the extreme end, an organization could "fork" an open source development project and add the critical components it needs. In the end, an open-source software program always offers greater flexibility to end-users, since any end user can take the program and modify it for their needs.

Large scale open-source projects such as Linux, FreeBSD, or Apache tend to discredit this argument. However, even within these very successful projects, there are sometimes technological components missing due to the fact that no one has the time or effort to volunteer to do them, nor a commercial company whose interests cause it to fund such work. Of course, this also applies to proprietary products; proprietary products also omit technological components because the expected return is less than other alternatives, even if they are important to a particular customer. It is also worth mentioning that most of the venture capital money is not going to open source companies today. Instead, many open source projects are either legacy code like FreeBSD or Apache which were developed long time ago independently of the open source movement, or companies like Netscape which donate its source code to open source with the hope that they can compete better, or companies like MySQL which use open source to lure customers for its more expensive licensed product. This argument is weakened by the fact that most of these projects have seen major or even complete (in the case of the Netscape code, for example) rewrites and don't contain much of the original code.

Security

Open source advocates usually believe that open source programs are more secure, mostly because they argue, everybody can see and fix it. On the other hand, they mostly ignore whether someone actually looks at the code or not. There is no accepted credible source that shows opening up the source code actually provides any sort of security.

Open source advocates also claim that open source programmers are very quick to fix bugs or security problems, though they neglect to mention that most of those fixes are raw fixes which must then be tested by the open source bundlers. In some cases testing is up to the end user.

Some proponents of proprietary or closed source software believe that open source software is more susceptible to security problems due to the availability of its source code. They also believe that the main factor which causes exploitation of proprietary software such as Microsoft Internet Explorer is its large market share, making it an attractive target for attackers. In response, proponents of open source software may believe that the availability of open source code leads to faster discovery of security issues, and faster resolution of these issues. This approach is also used in cryptography: it is believed that a secure encryption scheme has to be able to withstand attacks from people who have access to the code, and that security through obscurity is not a good thing. Though, cryptography and software development are very much different things. Opening up the source code may in fact hurt the security significantly. For example, many open source web programs using php have serious security problems and although these problems are being fixed, they are only fixed when affected end users prompt the developers about the problem.

Open source advocates

Bruce Perens, Eric Raymond, Linus Torvalds, Paul Vixie, Alan Cox, Tim O'Reilly, Brian Behlendorf, Russell Pavlicek (author of the book Embracing Insanity)

Projects and organizations

• Debian, FreeBSD, Mozilla, NetBSD, OpenBSD, Linux, OpenOffice.org, Open Source Initiative, OSTG, Slackware, BerliOS, SourceForge, NOSI, GNU, GOCC

Examples of open-source licenses

• BSD license, GNU General Public License, GNU Lesser General Public License, MIT License, Apache Software License, Mozilla Public License, Open Gaming License

For a more extensive list, see Open source license.

Examples of open-source software

• Apache, Linux, BSD, Mozilla, GNU Emacs, TeX, Vim, XFree86, GIMP, PHP, Zope, KDE, GNOME, OpenOffice.org, MySQL, Moodle, Postnuke, phpBB, GnucDNA , Shareaza, RPGToolkit

For a more extensive list, see List of open-source software packages.

Related topics

• Free/Libre Open Source Software
• Open content for non-programming open source projects
• Openness the philosophic term
• Open Source Funding
• Open Source Software
• Richard Stallman is a central figure in the rival (but cooperative) free software movement, which has a significantly different philosophical basis; Stallman does not want his name associated with the term open source.
• Open Source Culture

See also

• Free software
• Gift economy
• GNU Savannah
• Halloween documents
• List of open-source software packages
• OpenCola
• Open Law project
• SourceForge

Contrast with

• Freeware
• Shareware
• Proprietary software

External links

On the creation of the name "Open Source"

• Goodbye, "free software"; hello, "open source" http://www.catb.org/~esr/open-source.html Raymond's announcement of the term "open source", 8 February 1998
• It's Still Free Software http://lwn.net/1998/0219/a/rms.html 16 Feb 1998, Richard Stallman. The terminology battle begins.
• "It's Time to Talk About Free Software Again" http://lists.debian.org/debian-devel/1999/02/msg01641.html 12 months later, Bruce Perens chimes in.
• Why "Free Software" is better than "Open Source" http://www.gnu.org/philosophy/free-software-for-freedom.html - a later essay from FSF.

General links about open source

• ItresDotOrg Wiki http://www.itres.org - a wiki dedicated to the Open Source world.
• The Asian Open Source Center http://www.asiaosc.org - has a lot of information on open source in Asia, much of it stored in a Wiki similar to Wikipedia.
• Database of Open Source Bounties, Call for Tenders and Grants http://www.opensourcexperts.com/bountylist.html .
• Directory of Open Source Solution Providers Worldwide http://www.opensourcexperts.com/Index/index_html .
• JBoss, Professional Open Source http://www.jboss.org .
• A Case Against Open Source http://stlr.stanford.edu/STLR/Articles/01_STLR_4/article.htm , by Mathias Strasser, 2001, from Stanford Technology Law Review
• EU-funded report on the use of open-source software http://www.infonomics.nl/FLOSS/report/
• Fundamental issues with open source software development http://firstmonday.org/issues/issue9_4/levesque/index.html a personal review by Michelle Levesque.
• Groklaw - Open Source Software: What Is It and How Does It Work?" - By Dr. Ben Kremer http://www.groklaw.net/article.php?story=2004040421042728 - Good general overview of open source and the GPL.
• The Institutional Design of Open Source Programming: Implications for Addressing Complex Public Policy and Management Problems http://www.firstmonday.org/issues/issue8_1/schweik/index.html
• Open reSource: a wiki on the market, companies, investors, trends. http://sterneco.editme.com
• Open Source: Open for Business http://www.csc.com/features/2004/48.shtml
• The Open Source Alternative: Shrink-Wrap, Open Source and Copyright http://www.murdoch.edu.au/elaw/issues/v10n4/halbert104.html by Debora Halbert Ph.D., vol. 10, No. 4 (Dec. 2003) Murdoch University Electronic Journal of Law - Copyright Policy
• Open Source HealthCare Alliance http://www.oshca.org/
• Open Source Initiative (OSI) http://www.opensource.org/index.php - a list of available licenses
• Open Sources: Voices from the Open Source Revolution http://www.oreilly.com/catalog/opensources/book/toc.html - an online book containing essays from prominent members of the open source community
• W3C Open Source Software http://www.w3.org/Status
• Open Source Gaming http://osgaming.net/
• Rewriting Reality http://ceh.kitoba.com/worldview/reality.html Open Source Worldview Construction
• Why Open Source Software / Free Software? Look at the Numbers! http://www.dwheeler.com/oss_fs_why.html provides quantitative information on OSS
• Collaborative Source Software http://www.methodsandtools.com/archive/archive.php?id=11 - This article presents an approach to combine the best of the open source and proprietary software development worlds.
• Brief History of the Open Source Movement http://www.openknowledge.org/writing/open-source/scb/brief-open-source-history.h
  tml (opinion)
• Open source versus proprietary software: a discussion http://www.matthewbarr.co.uk/opensource.htm

This article is part of the series: forms of software distribution
Adware | Beerware | Careware | Crippleware | Donateware | Free software | Freeware | Hostageware | Nagware | Open source | Postcardware | Shareware | Shovelware |