freeopensource

Free and open-source software (FOSS) refers to software distributed with source code that anyone can inspect, modify, and redistribute. It embodies two closely related ideals: freedom for users to run, study, modify, and share software, and the availability of the source code so others can review and improve it.

History and terminology: The Free Software Foundation and the GNU project popularized the concept in the 1980s. In 1998 the Open Source Initiative helped promote the term "open source" to emphasize practical benefits and collaborative development.

Licensing: FOSS is released under licenses that grant these rights. Licenses are broadly categorized as copyleft (e.g., GNU General Public License) which requires derivative works to carry the same license, and permissive (e.g., MIT, BSD, Apache) which impose minimal restrictions on redistribution.

Benefits: Transparency, security through public review, and broader collaboration are core advantages. Open-source licenses enable interoperability, vendor independence, and new business models based on services, support, or dual licensing.

Challenges: License compliance and license compatibility can be complex; sustainability of projects often depends on active communities and funding. Security relies on timely maintenance, supply-chain governance, and responsible patching.

Notable examples: The Linux kernel, the GNU toolchain, the Apache HTTP Server, Mozilla Firefox, LibreOffice, Python, and Kubernetes illustrate the breadth of free and open-source software across operating systems, web servers, office suites, and cloud platforms.