What is Open Source Software?

The open source term refers to the public release of the source code of a software that before it is converted into machine language, in a way that can be read and understood by everyone.

Open source software is developed in a decentralized and collaborative way, based on peer review and community generation. Open source software is generally cheaper and more flexible. It is frequently updated, reviewed and tested, as it is developed by communities rather than a single person or company. For this reason, it is longer lasting and safer than other software. In addition, what information the software uses for what and where, or what changes are made in the source code are always clearly visible and transparent.

This movement, which has become a way of working beyond software production, uses the values of open source software and the decentralized production model to find new ways to solve problems in communities and industries.

The Brief History of Open Source Software

In fact, there were similar approaches before the concept of software. In the early days of automobile manufacturing, George B. Selden, the owner of the two-cycle gasoline engine patent, was able to create obstacles for entrepreneurs who would to manufacture cars. Following the elimination of this situation with the lawsuit that Henry Ford won against Selden, the newly established Motor Vehicle Manufacturers Association provided free sharing of new inventions among the members with a multi-directional sharing agreement. Until the United States entered the Second World War, more than 600 patents were shared by all members free of charge and without need have court.

In the early years of its foundation, IBM donated the source code of its operating system to a group called SHARE, which is founded inside of IBM and shared technical information and software between themselves.

In the 1950s and 1960s, researchers who have been developing early internet technologies and telecommunication network protocols united in ARPANET (Advanced Research Projects Agency Network), which would later form the basis of the modern internet, aiming the promotion of peer review and an open feedback process in an open and collaborative research environment.

Free, Closed Source and Open Source Software

For a long time, open source software was known as “free software”. The free software movement was formally founded in 1983 by Richard Stallman through the GNU Project. It was organized around the idea of ​​user freedoms such as seeing the source code, modifying it, redistributing it.

Closed source software is highly protected. Only owners of source code are legally entitled to access this code. The closed source code cannot be legally modified or copied, and the user only pays to use the software as intended, meaning that he cannot modify it for new uses or share it with their community.

Free software is the opposite of closed source software. However, the name “free software” has caused confusion. Contrary to the misunderstanding, free software does not mean freedom to have it, you are only free about how you want to use it. According to Christine Peterson, who coined the term “open source”, the problem with “free software” was not political connotations. The problem was that people new to the term actually focused on price. There was a need for a term that focuses on the core problem of source code and does not immediately confuse people new to the concept. For this reason, Peterson proposed the idea to replace the term “free software” with the term “open source” to a working group that was partially dedicated to driving open source software applications to the wider market.

Eric Raymond, one of the members of this group, made reference to these arguments in his 1997 article titled “The Cathedral and the Bazaar”. In 1998, Netscape open-sourced the Mozilla project, which would later become the basis for Mozilla Firefox and Thunderbird which are open source projects, partially in response to this article, and released the source code as free software. This prompted the community to consider the practical commercial aspects of the free software movement. Thus, the term “open source” would serve as a term supporting the methodological and commercial side of free software, while “free software” would remain a label for speeches emphasizing the philosophical aspects of the same topics.

Also in 1998, Open Source Movement (OSI) was formed, formalized the term open source, and created a common industry-wide definition. From the frontiers of software production, OSI has become the industry standard today, although it continued to be met with cautious and corporate doubts from the late 1990s to the early 2000s.

Figure 1: Open Source Initiative Logo

Open Source Licenses

First of all, in order for a software to be considered open source, it must be published with a license that meets the definition of open source. Open source licenses generally allow the software to be freely used, modified, and shared. In order for a license to be approved, it must go through a license review process conducted by the OSI.

Popular Licenses

Today there are many licenses that are OSI certified, widely used and with a strong community. You can check out the most popular open source licenses from the list below.

  • Apache License 2.0
  • BSD 3-Clause “New” or “Revised” license
  • BSD 2-Clause “Simplified” or “FreeBSD” license
  • GNU General Public License (GPL)
  • GNU Library or “Lesser” General Public License (LGPL)
  • MIT license
  • Mozilla Public License 2.0
  • Common Development and Distribution License
  • Eclipse Public License version 2.0

There are many more licenses besides this list. You can view all licenses here.


  1. Wikipedia. Open-source software
  2. Opensource. What is open source software?
  3. RedHat. What is open source?
  4. GNU. What is free software?

Leave a Reply

Your email address will not be published. Required fields are marked *