FreeBSD

FreeBSD is a free, open-source, Unix-like operating system based on Berkeley Software Distribution (BSD) Unix. It is the most popular among the BSD-based operating systems, with an installed base of more than 75%. Due to legal constraints, FreeBSD cannot be labeled as a Unix system, although it is compliant with Unix internals and application programming interfaces (APIs). FreeBSD’s licensing terms give developers a high degree of freedom to reuse it, so other operating systems (such as MAC OSX) have reused many FreeBSD codes. Although FreeBSD is not categorized as Unix, MAC OSX does have a formal Unix branding.

FreeBSD is used by millions of users all over the world, as well as some of the busiest sites on the Internet such as Yahoo, Sony Japan, etc.

Users attest to the reliability of FreeBSD, its amazing stability, and high performance are due to the following:

• FreeBSD is a complete operating system environment with a kernel, device drivers and a shell tool. In contrast, most Linux-based operating systems have a separately-developed kernel, application, and userland utilities.
• Several emulation tools are built into FreeBSD, allowing third-party software package installation, most of which employ the FreeBSD ports system.
• FreeBSD supports a wide variety of networking protocols, including TCP/IP, IPv6, Stream Control Transmission Protocol (SCTP), IPSec, Internetwork Packet Exchange (IPX), and AppleTalk, allowing users to integrate FreeBSD-based computers with other operating systems running within the same network.