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Berkeley Software Distribution - BSD redirects here; for other uses see BSD (disambiguation).
Berkeley Software Distribution (BSD) is the name of 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. History AT&T Bell Laboratories permitted Berkeley and other universities to use and extend the source code to their UNIX operating system in its infancy. Berkeley used the software as a research base for investigations into operating system design through the 1970s and 1980s. Eventually, the systems that Berkeley students had developed for their research had replaced almost every component of the AT&T UNIX system, and in the early 1990s the full Berkeley source code was released to the public under the BSD License. This led to a copyright lawsuit between AT&T and Berkeley, USL v. BSDi, which was settled almost entirely in Berkeley's favor, conclusively establishing BSD's free nature. While the lawsuit was still pending however, it cast a significant doubt over whether the Berkeley distribution would remain free. The case lasted nearly two years, and in this time the Linux kernel was released and proliferated. Linus Torvalds, the initial creator of the widely used Linux kernel, has stated that if there had been a free Unix like operating system that could run on 386 architecture (a 386 port of BSD was underway at the time) he likely would not have created Linux. Although it is debatable exactly what effect that would have had on the software landscape since, there is little doubt that it would have been substantial. Today BSD is developed as a number of descendent free software projects. It is also used in countless proprietary software products, as permitted by the BSD license. For example, Microsoft used BSD-derived code (acquired from a small Scottish company, Spider) in early implementations of TCP/IP for Windows, some of which may still be in use in later versions. In addition, many of the basic command-line network utilities bundled with Windows NT-XP are direct re-compiles of BSD's comparable programs. Technology BSD pioneered many of the advances of modern computing. Berkeley's Unix was the first to include library support for the Internet Protocol stacks, Berkeley sockets. By integrating sockets with the UNIX operating system file descriptors, users of their library found it almost as easy to read and write data across the network, as it was to put data on a disk. The AT&T laboratory eventually released their own STREAMS library, which incorporated much of the same functionality in a software stack with better architectural layers, but the already widely-distributed sockets library, together with the unfortunate omission of a function call for polling a set of open sockets (an equivalent of the select call in the Berkeley library), made it difficult to justify porting applications to the new API. Today, it continues to be used as technology testbed by academic organizations, as well as high-technology examples in a lot of commercial and free products. It is increasingly being used on embedded devices as well. The general quality of its source code design and clean writing, as well as its documentation (especially reference manual pages, commonly referred to as "man pages"), make such systems a heaven for programmers. BSD systems also are still being used in many government facilities. NetBSD is one of the more portable operating systems today, running on as much as 54 different platforms. For this reason, it represents a strong competitor in quickly evolving hardware markets, such as embedded systems and handheld devices, while still being adequate for large 64-bit servers using Alpha, Sparc64, or Opteron processors. It also yields great performance. This operating system lately was chosen to break recent internet transfer speed records because of the scalability of its TCP/IP stack implementation. This operating system is known to live on the International Space Station. The FreeBSD operating system is known as one of the most performant operating systems in existence. Although mostly focusing on user friendliness and i386 architecture, it lately was ported to other very popular architectures such as the PowerPC. It remains a good choice for cheap SMP (Synchronous Multi-Processor) capable hardware. The DragonFly BSD project, although still in its early stages, especially targets SMP and networked clusters performance. It appears to have a very promising future. Visit their site for more information about their current status and their technical restructuring goals. The OpenBSD project is widely known for its emphasis on cryptography and proactive security. Although other BSDs are also considered very secure operating systems, and usually also comport cryptography, several popular utilities, also commonly used on non-BSD systems such as Linux based ones, notably OpenSSH, were originally created by the OpenBSD team. Many corporations use BSD derived code while being able to maintain their intellectual property (IP) because of the versatility of the BSD license, which is less restrictive than the GNU General Public License used by many other free software such as the Linux and GNU projects. This also means that you may be owning hardware internally running parts of BSD software without knowing it. Try looking for signs of "University of California, Berkeley" in the documentation of products, in the static data sections of binaries and ROMs, or as part of the "about" available through the user interface frontend of many products. Surprise (or lack thereof) might ensue. It is an interesting fact that BSD operating systems can run native software of several other operating systems on the same architecture, using binary compatibility. This, much faster than emulation, allows for instance to run applications intended for Linux on a BSD operating system at full speed. This makes BSDs not only suitable for server environments, but also for workstation ones, considering the increasing availability of commercial or closed-source software for Linux. It also allows to migrate old commercial software which only used to run on commercial UNIX platforms to a modern BSD operating system, while retaining functionality of the previous system until it can fully be replaced by a better alternative. Finally the BSD operating systems are notable for their standards conformance. Common IEEE, ANSI, ISO, POSIX, X/Open and BSD standards compliance is retained as much as possible. Structure 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. BSD descendants Current Unix-like operating systems that descend from BSD include: See also External links Further reading
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