Software Licenses, Free and Open Source Software Péter Jeszenszky Faculty of Informatics, University of Debrecen
[email protected] Last modified: April 16, 2020 Terminology ● Non-Free Software, Closed-Source Software, Proprietary Software ● Free Software ● Open-Source Software ● Free and Open-Source Software (FOSS) ● Commercial Software ● Freeware, Shareware ● Software License ● End-User License Agreement (EULA) ● License Compatibility ● Copyleft, Copyleft License ● Public Domain ● Dual Licensing, Multi-Licensing 2 Non-Free Software ● Non-free software is any software that is not free. – Its use, redistribution or modification is prohibited or restricted, or requires permission. – It is also called as closed source software or proprietary software. – Non-free software is the complementary set of free software. 3 Free Software ● The four essential freedoms: – The freedom to run the program for any purpose. – The freedom to study how the program works. – The freedom to redistribute copies of the program. – The freedom to modify the program. ● Access to the source code is a precondition for the second and the fourth freedom. ● See: The Free Software Definition https://www.gnu.org/philosophy/free-sw.html.en 4 Open Source Software (1) ● The terms “free software” and “open source software” refer to almost the same range of software. However, they represent two different approaches. – Definition: The Open Source Definition https://opensource.org/docs/osd ● The term “open source” is more suitable for marketing purposes than the “term free” software. – Free is an ambiguous word. One meaning of the word is “at no cost”. ● See, for example, “free speech” vs “free beer”. 5 Open Source Software (2) ● The free software movement emphasizes the ethical aspects of freedom.