Open source

from Wikipedia, the free encyclopedia

As open source (from English source open , literally open source ) is software called whose source code can be modified and used in public and seen by third parties. Open source software can mostly be used free of charge.

Software can be made open source software by individuals for altruistic motives as well as by organizations or companies in order to share development costs or to gain market share .


Open source has many origins and precursors, such as the do-it-yourself movement, the hacking movement of the 1960s / 1970s, and the free software movement of the 1980s, which became the immediate forerunner.

Influenced by the essay The Cathedral and the Bazaar by Eric S. Raymond , published in 1997 , Netscape decided in 1998, in view of the growing dominance of Microsoft in the browser market, to release the source code of the economically no longer usable Netscape Navigator (this release resulted later the Mozilla project).

Shortly thereafter, Raymond, computer scientist Bruce Perens, and Tim O'Reilly , founder and director of O'Reilly Publishing , decided that the free software community needed better marketing . In order to be able to present this free software as free of ethical values ​​and business-friendly, it was decided to introduce a new marketing term for free software - the term open source was used nationwide in marketing from then on and was also the namesake for Raymond, Perens and O'Reilly founded Open Source Initiative (OSI). Adapted open source licenses were created that meet the needs of the open source environment and should also be attractive for commercial enterprises ( permissive licenses ). One of the most famous licenses that emerged from these endeavors is the Mozilla Public License .


Definition of the open source initiative

The Open Source Initiative (OSI) applies the term open source to all software whose license agreements correspond to the following three characteristic features and which meet the ten points of the open source definition :

  • The software (i.e. the source text) is available in a form that can be read and understood by humans : As a rule, this form is the source text in a high-level programming language . Before the actual program (run) it is normally necessary to convert this text into binary form using a compiler so that the computer program can be executed by the computer. Binary programs are practically unreadable for humans in the semantic sense.
  • The software may be copied, distributed and used as required : There are no restrictions on the use of open source software, either with regard to the number of users or the number of installations. The duplication and distribution of open source software does not entail any payment obligations towards a licensor. Typically, only the source text must be passed on.
  • The software may be changed and passed on in the changed form : Thanks to the source text disclosed, changes are possible for everyone without further effort. Distribution of the software should be possible without license fees. Open source software is downright dependent on the active participation of the user in the development. Open source software is ideal for learning, participating and improving.

However, open source does not mean, as is often assumed, everything-is-allowed ; there are conditions attached to its use. Completely unconditional use typically only exists with software in the public domain . That is why a BITKOM report on the subject of open source software gives the following correct description: “Utilization, duplication and processing is not permitted without reservation, because with open source software the granting of rights of use is often made dependent on certain requirements. In this way, open source software can be distinguished from public domain software […]. In the case of public domain software, the user is allowed to reproduce, distribute and change without restriction and without reservation. "

In practice, open source software (OSS) has great overlaps with free software , as defined by the FSF . Both concepts have in common that the source code of software should be available to users. The same copyleft and permissive software licenses are also classified as "free" or "open" by both sides, with a few rare exceptions. The primary difference lies in the terminology and point of view: Free software focuses on the aspect of user control over software and sees free software as an important social, political and ethical concern. The OSI takes the view that the practical benefit for the general public (users, society, companies, etc.) of a freely available software infrastructure, a free software market and a collaborative development method are the decisive aspect.

Further definitions

Open source, derived “open” concepts and associated properties: openness, transparency, collaborative work

The term open source is not limited to software, but is also broadly extended to knowledge and information. In addition, the free software movement has inspired the founding of many new “open” movements in other areas, such as open content , open source hardware and open access .

An example of this is Wikipedia and the Wikimedia Commons , in the context of which one speaks of free content ( open content ). Other important examples of Open Content are OpenStreetMap and Open Educational Resources . A family of licenses created for such free content (“free cultural works”) are the Creative Commons licenses.

The idea of ​​public and free access to information was also carried over to development projects. In this context, there is often talk of free hardware ( open hardware ), i.e. free access to all information ( open standard , open format ) in order to produce a corresponding hardware. Product examples based on open standards and recipes are Vores Øl / Free Beer or OpenCola.

The FabLabs , who want to provide free access to (production) hardware , also see themselves as “open” and closely related to the open source and open hardware movement .

Another example is the open source seed license , which tries to transfer the principle to plant breeding. Non-profit breeders can equip new varieties with a viral license ( copyleft ) so that the genetic material can no longer be transferred to a private good.

Open Access tries to provide free access to academic literature and other materials on the Internet and to reduce paywalls . Similarly, open government tries to make it easier for citizens to access government resources.

Definition conflict with "Free Software"

The terms open source software and free software are often used synonymously, but there is the possibility of a differently pointed interpretation. Although the actual meaning of the open source definition hardly differs from free software , both terms can be used deliberately to trigger different associations. The term open source was introduced after the original term free software caused confusion, as it was often misunderstood as basically free software.

The older term Free Software has been used by the Free Software Foundation (FSF) since the 1980s . A misassociation of free software with freeware was common, since in English free can stand for free as well as freedom and free software is in most cases really available free of charge. As with free but really only freedom from the FSF was meant these coined the slogan " free speech, not free beer " - "free speech, not free beer " to an association of free software with free software counter.

The possible misinterpretation of the ambiguous word "free" was part of the motivation for the term open source , which became popular with Linux from the late 1990s . The suggestion came in 1998 from Christine Peterson of the Foresight Institute when founding the OSI and open source movement . The newly founded open source movement decided to establish open source instead of the already existing FSF term free software , because it was hoped that the use of the term open source would remove the ambiguity of the term “free” and thus better acceptance of the Open source concept also enables the economy. In addition, the term open source avoided an association with the Free Software Foundation and the GNU General Public License ( GPL ), which can be problematic from an economic point of view. The term open source software should also emphasize a superiority of the collaborative, open development process (see The Cathedral and the Bazaar by Eric Steven Raymond ).

Since the introduction of the competing term Open Source , the FSF has criticized the fact that this term can also cause confusion. The term open source associates the availability of the source text, but does not say anything about the granted rights of use and freedom of use. An example of such confusion is the latest version of cryptography program PGP of the PGP Corporation : This is called open source touted as the source code can be considered, but this is subject to any open source license. Redistribution and modification of this source code are prohibited, so that the program does not fall under the open source definition. In response to this, GNU Privacy Guard was created, which meets the open source requirements through its GPL licensing.

Conversely, the GNU FDL , which the FSF regards as “free”, is criticized as not “open” and “free”. A problematic feature of the GNU FDL is that it offers the possibility of prohibiting the modification of certain sections, i.e. restricting the right to free further use. The GNU FDL therefore does not meet a fundamental requirement of the open source definition, the free software definition and the Debian Free Software Guidelines for software.

In order to avoid the conflict between Free Software and Open Source Software and to emphasize the similarities of the Open Source and Free Software movements , the terms FOSS and FLOSS (Free / Libre and Open Source Software) were suggested, which also achieved relevant dissemination.

Economical meaning

Application areas of open source software.

Open source often serves as the basis for commercial software. The Linux open source operating system is used as a platform on many embedded systems , home routers, set-top boxes and mobile phones . The commercial operating system webOS from HP Palm also benefits from Linux. Since these companies are dependent on Linux, they are also motivated to contribute to its development.

Software development companies can also offer support services for open source products . This is the case, for example, with the operating systems Ubuntu , Red Hat / Fedora and SUSE Linux . However, the source code is distributed free of charge.

Open source software can also be developed by volunteers for altruistic (selfless) motives. Larger projects usually come together to form a foundation, which is then financed by donations.

After open source software had initially established itself in the areas of server operating systems, web and mail servers, databases and middleware, open source software was able to gain an important role in commercial software in general. A study commissioned by the European Commission in 2006 examined the economic importance of open source for Europe. Accordingly, the market share has increased steadily in recent years. The study puts the total value at around twelve billion euros. In the four main areas of application (web server, programming languages, databases and server operating systems), 70% of Swiss users used open source software in 2015, which is a growth of 20% compared to 2012. The study forecast for 2010 32 percent of IT services are open source and advocates greater support for free software so that Europe can better exploit the economic potential of open source. The topic is therefore attracting increasing attention in business development . One example is the Stuttgart Region Economic Development Agency , which has started an initiative for an open source cluster .

Open source software was used much more frequently in companies than in public authorities.

Many open source projects have a high economic value. According to the Battery Open Source Software Index (BOSS), the ten most economically significant open source projects are:

rank Project Leading company Market value
1 Linux Red hat 16 billion
2 Git GitHub 2 billion
3 MySQL Oracle 1.87 billion
4th Node.js NodeSource ?
5 docker docker 1 billion
6th Hadoop Cloudera 3 billion
7th Elasticsearch Elastic 700 million
8th Spark Databricks 513 million
9 MongoDB MongoDB 1.57 billion
10 Selenium Sauce Labs 470 million

The given rank is based on the activity regarding the projects in online discussions, on GitHub, regarding the search activity in search engines and the impact on the job market.

Benefits of using

Survey on the reasons for using Open Source in 200 Swiss organizations.

Open source software is used by both companies and individuals. It offers a number of advantages:

  • Almost any number of people (and companies) can participate in the development of an open source program. The effort for the development is shared and everyone can benefit from the work of the others. If a company needs software and this is not part of the main product, it can be worthwhile for them not to buy the finished software or to start a complete in-house development, but to participate in an open source project.
  • Users of open source software are never dependent on a specific manufacturer. If a user wishes an extension or the correction of a program error , he is free to make this change or to instruct someone to do it. This is not possible with proprietary software and a change can only be requested from the manufacturer. This independence prevents the planned obsolescence of a software product , which is common with proprietary software, to the detriment of the user. Interoperability (e.g. data formats) is also possible with open source software , while this is often prevented by the lock-in effect with proprietary software .
  • The use of open source software is linked to few or no conditions. The software may be used by any number of users for any purpose. There are no license costs for duplication and further use.
  • Open source software enables insight into the source code and usually also the version history via the open development model . This makes it possible for everyone - for example using dedicated sites such as Ohloh - to analyze the software quality using static code analysis as well as the number of developers and their changes, and to draw conclusions about the maintainability and maturity of the software.
  • Checkability of a program for consciously introduced, user-unwanted mechanisms such as backdoors that could be used for political or economic espionage purposes. For example, Microsoft, as a provider of non-open source software, has problems refuting recurring rumors about NSA back doors in their operating systems because disclosure of the source code is not an option for Microsoft.


When asked what the important reasons for using open source are, it becomes clear that maximum flexibility is important to users when designing their IT landscape: for the vast majority of respondents, compliance with open standards (86%), Exchange of knowledge with the community (82%), cost savings (77%) and the reduction of supplier dependencies (76%) are the main motives for the use of open source.


To ensure ongoing support for open source projects, a number of conditions are necessary:

First of all, there should be an active community so that the knowledge is distributed among numerous people. One example of this is the Linux kernel . According to a kernel development study by the Linux Foundation from 2015, the proportion of Intel developers who contribute the most to the Linux kernel is only 10.5%. Even if Intel were to withdraw from Linux development, further development would still be ensured. It would be different, however, if the development is largely driven by an individual or company. In this case, the source code would be accessible to the general public, but important knowledge would be lost at the same time.

In addition, cooperation with commercial providers is important for the sustainability of open source projects. Developers who are not paid for the project but are paid for the work can devote more time to the project in the long term. For example, numerous smaller companies (such as Collabora ) are involved in the development of LibreOffice and sell certified versions of the program. At the same time, the developers are employed by the companies and develop the program full-time.

Finally, the existence of a non-profit organization that coordinates development and carries out marketing is also important. Coordination is important when developing software. In the case of proprietary software, this task is taken over by the owner of the software. In larger open source projects (such as the Linux kernel, LibreOffice or the content management system TYPO3 ), a non-profit organization connects the developer companies and the software users with one another. The non-profit organization can take the form of a foundation or an association . Marketing in particular has an important function, since in the software industry (for example at Adobe, Oracle or Microsoft) twice as much money is spent on sales and advertising as on actual software development.

In his book The Cathedral and the Bazaar, Eric S. Raymond describes a development method in which open source projects can be managed independently without centralized control by the community as a bazaar . Whether this development method is actually used or can be put into practice at all is controversial. For example, the Linux kernel , one of the big successful OSS projects , with Linus Torvalds at the helm, follows a more centralized development model with a Benevolent Dictator for Life ( benevolent dictator for life ) and corresponds to the cathedral in Raymond's terminology. Similar leadership structures can be found with Richard Stallman at the head of the FSF / GNU project and also at the Mozilla Foundation . The community-driven projects Apache Hadoop and OpenStack are cited as counterexamples .

Criticism and problems

In 2009, computer scientist Niklaus Wirth was critical of the technical quality of complex open source projects: The open source movement ignored and hindered the idea of ​​building complex software systems based on strictly hierarchical modules . Developers should not be familiar with the source code of the modules they are using. You should rely purely on the specifications of the modules' interfaces. If, as with open source, the source code of the modules is available, this automatically leads to a poorer specification of the interfaces, since the behavior of the modules can be read in the source code.

The FSF , and in particular its founder Richard Stallman , criticizes the open source movement in principle for neglecting socio-ethical aspects and concentrating only on technical and economic issues. In Stallman's opinion , the basic idea of free software is being neglected. The FSF also criticizes the company practice tolerated by parts of the open source movement of adapting the further developments of existing open source software to their own (hardware) systems to such an extent that they can practically no longer be used otherwise, e.g. B. tivoization or source text made illegible . The further development is then still under an open source license, but can no longer be used by the community; a situation that the FSF tries to prevent through the GPLv3 .

The ideal of open source, the free exchange and any further use of source text, is in reality through u. a. Limited licensing problems. This is particularly problematic due to the fact that the number of software licenses and version variants has now grown to a barely manageable number (and continues to grow), a problem known as license proliferation . Recognized open source licenses are also often incompatible with one another, which prevents further software use in some contexts. It is therefore advisable not to use any self-created or exotic open source licenses, the legal and practical problems of which you may not be able to oversee, but rather to use a tried, recognized and widespread free license (and license combinations) such as the GPL, the LGPL or to access the BSD license . The generous licenses in particular are characterized by very good license compatibility.

See also

Portal: Free Software  - Overview of Wikipedia content on the subject of Free Software


Web links

Wiktionary: open source  - explanations of meanings, word origins, synonyms, translations
Wiktionary: open source  - explanations of meanings, word origins, synonyms, translations (English)
Wikibooks: Open Source in Companies  - Learning and Teaching Materials

References and comments

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