FreeBSD
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FreeBSD
FreeBSD is a Unix-like free operating system descended from AT&T UNIX via the Berkeley Software Distribution (BSD) branch through the 386BSD and 4.4BSD operating systems. It runs on Intel x86 family (IA-32) PC compatible systems (including the Microsoft Xbox), and also DEC Alpha, Sun UltraSPARC, IA-64, AMD64, PowerPC and NEC PC-98 architectures. Support for the ARM and MIPS architectures are under development.
FreeBSD is developed as 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 (CVS). This is in contrast to other free operating systems such as Linux where the kernel, userland utilities and applications are developed separately and packaged together by other groups as Linux distributions.
As an operating system, FreeBSD is generally regarded as reliable and robust, and of the operating systems that accurately report uptime remotely, FreeBSD is the most common free operating system listed in Netcraft's list of the 50 web servers with the longest uptime. A long uptime also indicates that no crashes have occurred and that no kernel updates have been deemed necessary, as installing a new kernel requires a reboot and resets the uptime counter of the system.
History and development
Initial development of FreeBSD started in 1993, originating in the unofficial patchkit maintained by users of the 386BSD operating system. The first official release of FreeBSD was FreeBSD 1.0 in December 1993.
However, due to concerns about the legality of the BSD Net/2 release source code used in 386BSD and a consequent lawsuit between Novell (then owner of the UNIX copyright) and Berkeley, FreeBSD ended up re-engineering much of the system using the 4.4BSD-Lite release from the University of California, Berkeley, with the FreeBSD 2.0 release in January 1995. The FreeBSD Handbook includes more information about the genesis of FreeBSD.
Perhaps FreeBSD 2.0's most notable advance was the revamp of the original Carnegie Mellon University Mach Virtual Memory system, which was optimized for performance under high loads, and the creation of the FreeBSD Ports system that made downloading, building and installing third party software very easy. FreeBSD powered extremely successful sites like cdrom.com (a huge repository of software that broke several throughput records on the Internet), Hotmail, and Yahoo!.
FreeBSD 3.0 brought many changes: it switched to the ELF binary format and initial support for SMP systems and the 64 bit Alpha platform were added. At its time, the 3.X branch was severely criticized[citation needed] as many changes were not evidently beneficial and affected performance, but it was a necessary step to develop what would become the very successful 4.X branch.
Initially, FreeBSD employed the BSD Daemon as its logo, but in 2005 a competition for a new logo was arranged. On October 8, 2005, the competition finished and the design by Anton K. Gural was chosen as the new FreeBSD logo. The BSD Daemon will remain as the FreeBSD Project mascot.
Linux compatibility
FreeBSD provides binary compatibility with several other Unix-like operating systems, including Linux. This permits Linux programs to be run, including some commercial applications distributed only in binary form. Applications which use the Linux compatibility layer include StarOffice, the Linux version of Firefox, Adobe Acrobat, RealPlayer, VMware, Oracle, Mathematica, Matlab, WordPerfect, Skype, Doom 3 and Quake 4. There is said to be no noticeable performance penalty when running Linux binaries over native FreeBSD programs, and they may even be faster than the same binaries running on Linux[citation needed]. However, the layer is not completely seamless and some Linux binaries are unusable on FreeBSD or possess limited functionality: this is often as the compatibility layer only supports the system calls available in the historical Linux kernel 2.4.2, work is ongoing to provide Linux 2.6 support.
