FreeBSD

ROAM_REFS: https://en.wikipedia.org/wiki/FreeBSD

FreeBSD is a free-software Unix-like operating system descended from the Berkeley Software Distribution (BSD). The first version was released in 1993 developed from 386BSD—the first fully functional and free Unix clone—and has since continuously been the most commonly used BSD-derived operating system.

FreeBSD maintains a complete system, delivering a kernel, device drivers, userland utilities, and documentation, as opposed to Linux only delivering a kernel and drivers, and relying on third-parties such as GNU for system software. The FreeBSD source code is generally released under a permissive BSD license, as opposed to the copyleft GPL used by Linux. The project includes a security team overseeing all software shipped in the base distribution. Third-party applications may be installed using the pkg package management system or from source via FreeBSD Ports. The project is supported and promoted by the FreeBSD Foundation.

Much of FreeBSD's codebase has become an integral part of other operating systems such as Darwin (the basis for macOS, iOS, iPadOS, watchOS, and tvOS), TrueNAS (an open-source NAS/SAN operating system), and the system software for the PlayStation 3, PlayStation 4, PlayStation 5, and PlayStation Vita game consoles. The other current BSD systems (OpenBSD, NetBSD, and DragonFly BSD) also contain a large amount of FreeBSD code, and vice-versa.