BSDs

BSDs (Berkeley Software Distributions) are a family of Unix-like operating systems derived from the Berkeley Software Distribution, developed at the University of California, Berkeley. They are known for permissive open-source licenses, stable releases, and a cohesive software ecosystem. BSD licenses, including the two- and three-clause variants, permit wide use in both open-source and proprietary software with minimal restrictions.

The major BSD descendants are FreeBSD, NetBSD, OpenBSD, and DragonFly BSD. The lineage traces back to 386BSD and early BSD releases from Berkeley. Each project has its own emphasis: FreeBSD targets performance and a complete system; NetBSD emphasizes portability across a wide range of architectures; OpenBSD prioritizes security, correctness, and code auditing; DragonFly BSD focuses on performance, scalability, and advanced filesystem features.

Common features across BSDs include a monolithic kernel, a mature userland, and a robust ports or package management system. Notable strengths vary by project: FreeBSD offers Jails for lightweight virtualization and strong ZFS integration; OpenBSD is known for secure defaults and integrated cryptography; NetBSD is highly portable; DragonFly BSD provides the HAMMER filesystem and multiprocessing improvements.

BSDs are used in servers, networking gear, and embedded systems. They have influenced other operating systems; for example, macOS and iOS derive much of their userland and tooling from BSD-derived foundations. The combination of permissive licensing, stability, and a transparent development model contributes to ongoing adoption in both research and industry contexts.