Also known as: FOSS · free software · OSS
Open source software is software distributed under a licence that grants anyone the right to use, inspect, modify, and redistribute the source code, subject to conditions defined by that licence.
Licences divide broadly into permissive families such as MIT and Apache, which allow proprietary derivatives, and copyleft families such as the GPL, which require derivative works to be released under the same terms. The choice is a governance decision, not merely legal boilerplate.
Open availability of source does not by itself guarantee security. Many widely-deployed critical components are maintained by very small numbers of unpaid volunteers, a structural fragility that several high-profile incidents have made concrete.
Linux Distribution
A Linux distribution is a complete operating system built around the Linux kernel, bundling it with system libraries, a package manager, default utilities, and a curated set of software, along with policies for how all of it is maintained and updated.
Kernel
The kernel is the core of an operating system, responsible for managing memory, scheduling processes, and mediating all access between software and hardware. The Linux kernel is the component that makes a system 'Linux'.
Software Supply Chain Security
Software supply chain security is the practice of verifying the integrity and provenance of every component, tool, and process that contributes to a piece of software, from source dependencies through the build system to distribution.
Package Manager
A package manager is the tool that installs, updates, configures, and removes software on a Linux system, resolving dependencies automatically and verifying package integrity through cryptographic signatures.
Reproducible Build
A reproducible build is one where compiling the same source code with the same environment always produces a byte-for-byte identical binary, allowing anyone to independently verify that a distributed binary genuinely corresponds to its published source.