BSD ''Berkeley Software Distribution''

Berkeley Software Distribution

"BSD" redirects here. For other uses, see BSD (disambiguation). BSD Unix Beastie, the BSD daemon by Poul-Henning Kamp Website: N/A Company/ developer: CSRG, UC Berkeley OS family: Unix Source model: Open source Latest stable release: 4.4-Lite2 / 1995 Kernel type: Monolithic License: BSD license Working state: Superseded by derivatives (see below) Berkeley Software Distribution (BSD, sometimes called Berkeley Unix) is the Unix derivative distributed by the University of California, Berkeley, starting in the 1970s. The name is also used collectively for the modern descendants of these distributions. BSD is one of several branches of Unix operating systems. Another one is evolved from UNIX System V developed by AT&T's Unix System Development Labs. A third consists of the GNU/Linux operating systems which draw from Unix System V and BSD, as well as Plan9, and non-UNIX operating systems. BSD was widely identified with the versions of Unix available for workstation-class systems. This can be attributed to the ease with which it could be licensed and the familiarity it found among the founders of many technology companies during the 1980s. This familiarity often came from using similar systems—notably DEC's Ultrix and Sun's SunOS—during their education. While BSD itself was largely superseded by the System V Release 4 and OSF/1 systems in the 1990s (both of which incorporated BSD code), in recent years modified open source versions of the codebase (mostly derived from 4.4BSD-Lite) have seen increasing use and development. Contents

The earliest distributions of Unix from Bell Labs in the 1970s included the source code to the operating system, allowing researchers at universities to modify and extend Unix. The first Unix system at Berkeley was a PDP-11 installed in 1974, and the computer science department used it for extensive research thereafter.

Other universities became interested in the software at Berkeley, and so in 1977 Bill Joy, then a graduate student at Berkeley, assembled and sent out tapes of the first Berkeley Software Distribution (1BSD). 1BSD was an add-on to Sixth Edition Unix rather than a complete operating system in its own right; its main components were a Pascal compiler and Joy's ex line editor.

The Second Berkeley Software Distribution (2BSD), released in 1978, included updated versions of the 1BSD software as well as two new programs by Joy that persist on Unix systems to this day: the vi text editor (a visual version of ex) and the C shell.

Later releases of 2BSD contained ports of changes to the VAX-based releases of BSD back to the PDP-11 architecture. 2.9BSD from 1983 included code from 4.1cBSD, and was the first release that was a full OS (a modified Version 7 Unix) rather than a set of applications and patches. The most recent release, 2.11BSD, was first released in 1992, with maintenance updates from volunteers continuing until 2006 (patch 445 was released on December 26, 2006).
BSD pioneered many of the advances of modern computing. Berkeley's Unix was the first Unix to include libraries supporting the Internet Protocol stacks: Berkeley sockets. By integrating sockets with the Unix operating system's file descriptors, it became almost as easy to read and write data across a network as it was to access a disk. The AT&T laboratory eventually released their own STREAMS library, which incorporated much of the same functionality in a software stack with a better architecture, but the wide distribution of the existing sockets library, together with the unfortunate omission of a function call for polling a set of open sockets equivalent to the select call in the Berkeley library, reduced the impact of the new API.

Today, BSD continues to be used as a testbed for technology by academic organizations, as well as finding uses in a lot of commercial and free products and, increasingly, in embedded devices. The general quality of its source code, as well as its documentation (especially reference manual pages, commonly referred to as man pages), make it well-suited for many purposes.

The permissive nature of the BSD license allows companies to distribute derived products as proprietary software without exposing source code and sometimes intellectual property to competitors. Searching for strings containing "University of California, Berkeley" in the documentation of products, in the static data sections of binaries and ROMs, or as part of other information about a software program, will often show BSD code has been used. This permissiveness also makes BSD code suitable for use in open source products, and the license is compatible with many other open source licenses.

BSD operating systems can run much native software of several other operating systems on the same architecture, using a binary compatibility layer. Much simpler and faster than emulation, this allows, for instance, applications intended for Linux to be run at effectively full speed. This makes BSDs not only suitable for server environments, but also for workstation ones, given the increasing availability of commercial or closed-source software for Linux only. This also allows administrators to migrate legacy commercial applications, which may have only supported commercial Unix variants, to a more modern operating system, retaining the functionality of such applications until they can be replaced by a better alternative.

Current BSD operating system variants support many of the common IEEE, ANSI, ISO, and POSIX standards, while retaining most of the traditional BSD behavior. Like AT&T Unix, the BSD kernel is monolithic, meaning that device drivers in the kernel run in privileged mode, as part of the core of the operating system. Early versions of BSD were used to form Sun Microsystems' SunOS, founding the first wave of popular Unix workstations.

* FreeBSD, a major open source effort focusing on performance and the x86 platform
* NetBSD, an open source BSD with an emphasis on portability and clean design
* OpenBSD, a 1995 fork of NetBSD, focuses on portability, security, standardization and correctness
* DragonFly BSD, a fork of FreeBSD to follow an alternative design, particularly related to SMP
* MidnightBSD, a fork of FreeBSD to develop a desktop operating system utilizing GNUstep.
* PC-BSD, a variant of FreeBSD with emphasis on ease of use and user friendly interfaces for the desktop/laptop PC user
* DesktopBSD, another custom install of FreeBSD for the desktop/laptop PC user. It provides a number of graphical front ends to make learning FreeBSD less of a challenge.
* Tru64 UNIX (formerly DEC OSF/1 AXP or Digital UNIX), the port of OSF/1 for DEC Alpha-based systems from DEC, Compaq and HP.
* Apple Inc.'s Darwin, the core of Mac OS X; built on the XNU kernel (part Mach, part FreeBSD, part Apple-derived code) and a userland much of which comes from FreeBSD
* Juniper Networks JunOS, the operating system for Juniper routers
* Force10 Networks FTOS, the operating system for Force10 TeraScale E-Series switches/routers, based on NetBSD
* Nokia IPSO, the operating system for the Nokia IP security appliances