BSD Unix traces its roots to 1976 when Ken Thompson returned to Bell Labs. Bill Joy and Chuck Haley began optimizing the Unix kernel and bundling it with the Pascal compiler. In early 1977, Bill Joy released the Berkeley Software Distribution, or BSD.
Early BSD was not a standalone OS but a collection of software for existing Unix systems. Berkeley charged only for tape and distribution, helping the system spread to universities and research institutions. After the first BSD distribution, Joy improved the Pascal system and bundled it with vi, the C shell, and other tools to form the Second Berkeley Software Distribution, or 2BSD.
Joy personally handled every distribution request, taping and mailing copies himself. In 1978, a VAX arrival at Berkeley led to the integration of virtual-memory code, resulting in 3BSD, which shipped in December 1979. DARPA took notice of Berkeley's successful distribution of 3BSD to research institutions, recognizing Unix's portability.
BSD runs well on the VAX platform, cementing its role in operating system history.
Source: Hacker News · Summarized by HeadlinesBriefing