FreeBSD is a free Unix-like operating system descended from AT&T UNIX via BSD UNIX. Although for legal reasons FreeBSD cannot be called "UNIX", as a direct descendant of BSD UNIX, FreeBSD's internals and system APIs are UNIX-compliant. Due to its permissive licensing terms, much of FreeBSD’s code base has become an integral part of other operating systems such as Apple's OS X that have subsequently been certified as UNIX-compliant and have formally received UNIX branding. With the exception of the proprietary OS X, FreeBSD is the most widely used BSD-derived operating system in terms of number of installed computers, and is the most widely used freely licensed, open-source BSD distribution, accounting for more than three-quarters of all installed systems running free, open-source BSD derivatives. Characterised in 2005 as "the unknown giant among free operating systems", FreeBSD is a complete operating system. The kernel, device drivers, and all of the userland utilities, such as the shell, are held in the same source code revision tracking tree.. Third-party application software may be installed using various software installation systems, the two most common being source installation and package installation, both of which use the FreeBSD Ports system. Wikipedia [ - ]

FreeBSD is a free Unix-like operating system descended from AT&T UNIX via BSD UNIX. Although for... [ + ]