Glossary
Our glossary guides you through the most important terms and concepts relating to Free Software. Ideal for anyone who wants to deepen their understanding in this area.
Free Software
Free software refers to "freedom" rather than the "price" of software. The term "free" is often mistakenly equated with "no cost" or "gratis" due to misunderstanding. The concept of free software was defined in 1985 by the GNU Project, initiated by Richard M. Stallman in 1983, and includes the following freedoms:
- Unlimited right to use the software for any purpose.
- The ability to study how the software works.
- Permission to make and distribute copies of the software.
- The authority to make improvements to the software and to publish these improvements.
If any of these freedoms are withheld, the software is classified as proprietary or non-free software.
Open Source
Open Source was brought to live in 1998 by Eric S. Raymond, the founder of the Open Source Initiative (OSI), to establish a marketing term for Free Software, based on the freedoms mentioned above. However, the term has led to numerous misunderstandings. It suggests that the software is source-open, which is merely a prerequisite for fulfilling the four freedoms. Over time, licenses have been developed that disclose the source code but simultaneously prohibit improving the code.
We use the terms Free Software and Open Source synonymously on our webpages, but we align ourselves with the free software movement.
Free Software Licenses
Free Software is by no means license-free, as is often mistakenly claimed. A license that meets the criteria for Free Software does not restrict the user to just the right to use the software, as is the case with proprietary software. Since the source code is distributed with it, the user is free to adapt the software according to their wishes and to fix any errors. The modifications can ultimately be made available to the public, which benefits from the changes and may make further improvements to the software product.
Difference Between Copyleft and Non-Copyleft Licenses
Copyleft Licenses
Copyleft licenses protect Free Software from being incorporated into a proprietary software product, thus also securing the rights of programmers who have contributed to this software. Examples include the GNU GPL (General Public License) and the GNU LGPL (Lesser General Public License). A prominent example of software under a copyleft license is the Linux Kernel, which is released under the GNU General Public License (GPL), ensuring that all derivative works must also remain free.
Non-Copyleft Licenses
Non-copyleft licenses do not offer this protection. Examples include the BSD Copyright License, the MIT License, and the X11 License. Prominent examples of systems under such licenses are OpenBSD and FreeBSD, which are released under the BSD Copyright License.
Copyleft licenses protect Free Software from being incorporated into a proprietary software product, thus also securing the rights of programmers who have contributed to this software. Examples include the GNU GPL (General Public License) and the GNU LGPL (Lesser General Public License). A prominent example of software under a copyleft license is the Linux Kernel, which is released under the GNU General Public License (GPL), ensuring that all derivative works must also remain free.
Non-Copyleft Licenses
Non-copyleft licenses do not offer this protection. Examples include the BSD Copyright License, the MIT License, and the X11 License. Prominent examples of systems under such licenses are OpenBSD and FreeBSD, which are released under the BSD Copyright License.