Free-and-Open-Source-Software<\/a> (FOSS) is a classification of software that can be classified as both free software and open-source software. This means anyone is freely licensed to use, copy, study, and change the software in any way, and the source code is openly shared so that people are encouraged to voluntarily improve the design of the software. This approach stands in contrast to Proprietary-Software<\/a>, where the software is under restrictive copyright and the source code is usually hidden from users.<\/p> The movement is historically rooted in two distinct philosophies. The Free-Software-Movement<\/a>, launched by Richard-Stallman<\/a> in 1983 via the GNU-Project<\/a>, focuses on the moral and ethical rights of users. Stallman founded the Free-Software-Foundation<\/a> (FSF) to support these ideals, emphasizing the 'four freedoms' of software usage. More information on these principles can be found at the official GNU Philosophy page<\/a>.<\/p> Conversely, the Open-Source-Movement<\/a>, formalized by the Open-Source-Initiative<\/a> (OSI) in 1998, emphasizes the technical and collaborative advantages of open development. Key figures such as Eric-S-Raymond<\/a> and Bruce-Perens<\/a> argued that making source code available leads to better software through peer review. The OSI maintains the Open Source Definition<\/a>, which sets the criteria for open-source licenses.<\/p> Crucial to the ecosystem are Software-Licenses<\/a>. Copyleft<\/a> licenses, most notably the GNU-General-Public-License<\/a> (GPL), ensure that derivative works remain free. Permissive licenses, such as the MIT-License<\/a> and the Apache-License<\/a>, allow for the integration of code into non-free projects. The Linux-Kernel<\/a>, started by Linus-Torvalds<\/a>, remains one of the most successful examples of FOSS collaboration in history.<\/p>