FreeBSD

Background and history

FreeBSD is a free and open source UNIX-like operating system developed by the FreeBSD Project. FreeBSD is regarded as one of the most reliable and secure operating systems in the world and powers some of the internet’s largest web servers, including Yahoo’s and Sony’s (and more). FreeBSD's rock-solid stability and ability to perform extremely well under heavy workloads makes it a popular choice among internet service providers (ISPs) and web hosting companies, but FreeBSD is equally suitable for use in other kinds of enterprises. Of the operating systems that accurately report uptime remotely, FreeBSD is among the few system listed on Netcraft's list of the 50 web servers with the longest uptime.

FreeBSD descended from AT&T UNIX and originated at the University of California, Berkeley (1975) and evolved over time and multiple steps through the 386BSD and 4.4BSD operating systems to the project founded in 1993 known as FreeBSD. For a detailed account of FreeBSD's history refer to the History Chapter in the FreeBSD's Handbook or read "Twenty Years of Berkeley Unix. From AT&T-Owned to Freely Redistributable", an e-book written by Marshall Kirk McKusick. An interesting chart showing the history of UNIX/BSD can be found here. As a side note, FreeBSD is not called UNIX, but a UNIX-like operating system, since UNIX is a registered trademark owned by Novell.