FreeBSD Operating System

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) IBM PC compatible computers, Sun UltraSPARC, IA-64, AMD64, PowerPC, ARM and NEC PC-9801 architectures along with Microsoft's Xbox. Support for other architectures is in varying stages of development. The DEC Alpha architecture was previously supported between releases 4.0 and 7.0, with the code being removed for FreeBSD 7.0. FreeBSD currently has more than 200 active developers and thousands of contributors.

FreeBSD has been characterized as "the unknown giant among free operating systems." It is not a clone of UNIX, but works like UNIX, with UNIX-compliant internals and system APIs. FreeBSD is generally regarded as reliable and robust.

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, whereas with Linux distributions, the kernel, userland utilities and applications are developed separately, then packaged together in various ways by others.

FreeBSD 7.0 was released on 27 February 2008. The most recent FreeBSD 7 release was 7.2, on May 04, 2009. New features include SCTP, UFS journaling, an experimental port of Sun's ZFS file system, GCC4, improved support for the ARM architecture, jemalloc (a memory allocator optimized for parallel computation, which was ported to Firefox 3), and major updates and optimizations relating to network, audio, and SMP performance. Benchmarks have shown significant speed improvements over previous FreeBSD releases as well as Linux. The new ULE scheduler has seen much improvement but a decision was made to ship the 7.0 release with the older 4BSD scheduler, leaving ULE as a kernel compile-time tunable. In FreeBSD 7.1 ULE was the default for the i386 and AMD64 architectures.

Starting from version 7.1 DTrace was also integrated and FreeBSD 7.2 brought support for multi-IPv4/IPv6 jail

Pros: Fast and stable; availability of over 15,000 software applications (or "ports") for installation; very good documentation

Cons: Tends to lag behind Linux in terms of support for exotic hardware, limited availability of commercial applications; lacks graphical configuration tools