Berkeley Software Distribution

The Berkeley Software Distribution (BSD ) is a version of the Unix operating system that originated at the University of California at Berkeley from 1977. BSD is based on AT & T's Unix Sixth Edition (V6 ) and Seventh Edition (V7 ), which were made ​​from 1975 ( V6) and 1979 (V7 ) the universities for the price of the disks available as the company at this time, the telecommunications monopoly in the United States had held and therefore no business could make in the computer field, with permission to view the source code and modify. This permit was maintained even later for the purposes of teaching. Meanwhile, the complete source code is rewritten, there is no single line of AT & T source code in the current BSDs.

The original created by the University of BSD is hardly common. The term BSD called today rather a whole class of Unix derivatives, which have their roots in the actual BSD, such as early versions of SunOS and Ultrix. BSD is next to System V one of the two major main lines of Unix development.

Today, Mac OS X, the XNU kernel is based on Mach and builds on the userland from FreeBSD, the most common and commercially successful by far Desktop Unix variant in the computer market.

  • 4.1 Similarities and differences of the BSDs 4.1.1 Other BSD variants
  • 4.1.2 BSD derivatives

The BSD License

The source code of the distribution has been released by Berkeley under the BSD license, which is, in modified form today to is a free license, which is also used for other software packages. In contrast to the GNU General Public License allows the BSD license, in accordance with some rules to use the source code to develop their own, proprietary programs.

Innovations of Berkeley

BSD had great influence on the Unix development. It changes to the kernel were made, the system was otherwise substantially expanded. Many of these innovations were later adopted either directly or in a similar form in the competing system -V line.

The main changes were:

  • The Fast File System, faster file system that supports long file names ( the 7 edition only allowed 14 characters).
  • The Internet protocol network implementation.
  • The socket interface, a general network programming interface, which was acquired on other systems.
  • The virtual memory management on Unix was implemented at Berkeley.
  • New signals (previously 15 ), the Berkeley job control enabled SIGSTOP and SIGCONT

History of development

The following describes the history of the Berkeley Software Distribution is described by the acquisition of a copy of Unix from Bell Laboratories by UCB up to version 4.4 Lite2.

The beginnings

The University of Berkeley received in 1974 by AT & T 4- Edition of the still new operating system Unix. This had just been rewritten in C, a C-language development system was part of the system. Immediately began the expansion of the system, which ran on a PDP-11 machine from Digital Equipment Corporation ( Digital). The work accelerated, than in 1976, Ken Thompson, a significant Unix developers, a visiting professor at Berkeley took. Meanwhile, the 5 Series and 6 Series edition were published.

The enhancements and changes summarized the then student Bill Joy in 1977 for the first time together, and set them outside researchers on a magnetic tape available - the first Berkeley Software Distribution. So many new parts 1978 Been added that the second Berkeley Software Distribution ( 2BSD ) was compiled. This contained the first version of the vi editor.

VAX computer and DARPA influence

Meanwhile, Digital had released a new processor line called VAX, whose first representative was the VAX-11/780. VAX was actually called Virtual Address Extension and was originally conceived as an extension for the PDP -11 line. The VAX was but a separate processor line, and digital planned to stop selling PDP machinery in favor of the VAX line. AT & T had indeed been a port of Unix V7 on the VAX processor completed (Version 32 / V ), but this did not support virtual memory management. Berkeley ported 2BSD on the VAX-11/780 and implemented a virtual memory management. For VAX machines appeared in 1979 and then in 1980 3BSD 4BSD. The development of the BSD's for PDP - 11s was independent of continued with 2BSD because the address space of the PDP of only 64 KByte was too small for the new versions.

1980, a contract was concluded with the research department of the U.S. Department of Defense DARPA. 3BSD and 4BSD should be the basis for the DARPA developments, particularly in the area of networking. This resulted in the integration of the Internet network protocols (TCP / IP) in the BSD.

At the same time, AT & T decided their 7- Edition (V7 ) for System III and then further develop the System V and commercially marketable. Therefore, the new Berkeley version was not 5BSD but 4.1BSD order to avoid confusion. With 4.1a, 4.1b and 4.1c 4.1BSD and the internal versions of the performance of the system was improved, inserted first TCP / IP protocols and networking tools (rsh, rcp ) developed. This and many aid programs created by Berkeley prompted Sun, DEC, and other hardware manufacturers to build their versions of UNIX BSD, rather than on the official System V from AT & T. Thus BSD established in the academic and military fields. AT & T took over these developments later in their system V product. Since the Berkeley distribution included still early source code from AT & T, AT & T wanted to acquire a (expensive) license of anyone who used code from Berkeley.

The commercial era

Rise

Computer manufacturer took over the Berkeley Software Distribution and adapted them to their machines. 1982 Bill Joy joined the newly founded company Sun Microsystems, which brought out the first version of its BSD-based SunOS operating system in the same year. SunOS has been enhanced with many features of the already licensed system V in the course of its development history, but remained for a long time its BSD roots.

In 1983, out for PDP -11 Digital Ultrix -11 and VAX computers Ultrix -32. Ultrix was also based on BSD. It was later ported to the MIPS processors used the digital in its workstation line.

Other Unix vendors used parts of the BSD. So put NeXT in 1988 for their operating system NeXTSTEP a BSD system, but with a Mach microkernel, a. System V took over gradually code from BSD, it formed the basis of these Unix systems.

Case

Digital brought around 1990 out their Alpha microprocessor, which should replace the VAX and MIPS products. At the same time the development of Ultrix has been set as the new OSF / 1 on Alpha - a Unix clone - was offered.

Sun made in 1988 with Unix International an alliance with AT & T and ported her SunOS also on System V with BSD extensions. In 1992 sunos5 (also Solaris 2 ), which was not a direct descendant of BSD.

Thus, the last major Unix vendor had changed sides on System V, all Unix systems still used, however, large parts of BSD, including imported from BSD commands and the TCP / IP network implementation.

Further developments in Berkeley

Berkeley continued its tradition and further developed the distribution. In 1983 and 1986, 4.2BSD 4.3BSD. It was clear that the VAX processors had to be replaced by other systems with 4.3BSD -Tahoe (1988 ) of the kernel in machine-dependent and portable parts was separated, was published in 1990 with 4.3BSD - Reno a version that, among others, the Mach- microkernel supported.

4.3BSD has even been ported to the PDP-11 machines (back) and published in 1992 as 2.11BSD. The 250 -Kbyte kernel was here shown with overlay techniques on the only 64 -kbyte address space of the PDP.

BSD and AT & T's Unix source code

The late 1980s, Berkeley had built so many extensions that almost all of the Unix source code from AT & T was replaced with your own versions. Manufacturer of Unix versions based on BSD still had to because of the other elements constituting a (expensive) System V license from AT & T purchase. Because, among other things originated the entire network implementation of Berkeley, had other manufacturers interested in the Berkeley developments, but without having to purchase an AT & T license. In 1989, the University therefore the Networking Release / 1 out, which included all the files identified by Berkeley without code from AT & T. However, this version was not a complete operating system longer represent

In 1991 appeared the Networking Release / 2 Bill Jolitz 1992 added this release to only six files and published a patch, so that was a complete, advanced operating system for Intel 80386 processors called 386BSD.

Also in 1992 started a company established by the University of Berkeley company called Berkeley Software Design Inc. ( BSDI ) The marketing of even the operating system advanced Networking Release / 2 They marketed their system under the name of Unix including the source code for the lower price of $ 995. The Unix System Laboratories ( USL ), a branch of AT & T, sued BSDI and the University then. To stop selling for trademark infringement and partial use of its source code An injunction was refused.

In the course of this litigation, however, the authorship of Berkeley pointed out that AT & T code had taken over from Berkeley (which was legal because of the BSD license ), while from the source code and documentation removed had (which is prohibited in the BSD license ). The dispute ended in 1994 with the fact that AT & T had to enter in some of its files authorship of Berkeley again. Berkeley had to remove Release / 2 and perform some small changes only three of the more than 18,000 files of networking. The release was thus free of Unix source code.

In the same year Berkeley was then the version 4.4BSDLite as a successor to the Networking Release / 2 out. 1995, then the version 4.4BSDLite2 the latest version of the Berkeley Software Distribution. 4.4BSDLite and Lite2 were together with 386BSD the basis of NetBSD, FreeBSD and OpenBSD shortly thereafter.

The BSDi developed and marketed their system continue under the name of BSD / OS. In 2001 BSDi was acquired by Wind River Systems, California.

Version History

  • First BSD version of UNIX developed by Bill Joy
  • Support for PDP -11
  • Extract (programs): Pascal, ex
  • Development ( PDP 11)
  • Porting 2BSD on VAX
  • First virtual memory management
  • Development ( VAX )
  • Extract (programs): mail, job control
  • Development ( PDP 11)
  • Development ( VAX )
  • Various performance improvements
  • Internal versions: BSD4.1a, BSD4.1b, BSD4.1c
  • Network development
  • Various performance improvements
  • Development ( PDP 11)
  • New file system, TCP / IP
  • Robust network implementation
  • Various performance improvements
  • Separation of the machine-dependent and portable kernel parts
  • Latest version and further development of the original PDP-11 line
  • Networking Release / 1
  • Networking Release / 2 (also 4.3BSD - Lite)
  • Backport from 4.3BSD to the PDP -11
  • Commercial version of Berkeley Software Design, Inc. with support for Intel i386 processors
  • Port of 4.3BSD -Lite on Intel i386 processors by Bill Jolitz
  • First completely from AT & T source code free version ( 4.4BSD- Encumbered also )
  • Development ( 386BSD )
  • Additional support for Sun SPARC and PowerPC processors
  • Last release of the Berkeley Software Distribution

The projects NetBSD, FreeBSD and OpenBSD

The free 386BSD (1992 ) by Bill Jolitz attracted developers, especially as PCs were very inexpensive 80386. Jolitz was permanently employed and did not always have enough time for troubleshooting and incorporation of suggestions for improvement. This prompted some developers in 1993, two follow-up projects, NetBSD and FreeBSD to call almost simultaneously into life.

After 1994, the dispute with AT & T was settled, both projects brought new versions based on 4.4BSD -Lite that will contain no AT & T code more: NetBSD 1.0 (1994) and FreeBSD 2.0 ( early 1995 ).

1995, fell out of one of the founders of the NetBSD project, Theo de Raadt, with the other developers and split off a separate project called OpenBSD. Since 2003, with DragonFly BSD, a fork of FreeBSD, another BSD Project. The operating system Mac OS X and its open-source counterpart Darwin from Apple, based in parts (which the "normal" GUI-oriented, user hardly notices ) on BSD, especially FreeBSD. The continuation and further development of NeXTStep as Mac OS X BSD learned again a technological boom and a very strong distribution.

Similarities and differences of the BSDs

New developments and in particular the numerous device drivers of a project are taken from the other irregular. All projects have to develop a free system to the target, the actual system should therefore be weighed solely with the BSD license compatible code. The details of the interpretation of the term free software, however, differ slightly.

NetBSD would like to support as large a number of different hardware architectures and processors. Of course it runs NetBSD is the slogan of the project. A special attention is paid to the implementation of a system-wide, clean design and a clear structure. This includes the creation and continuous improvement of machine- independent interfaces, eg for device drivers that allow the proverbial portability of NetBSD in the first place.

Because of his public relations FreeBSD is one of the most popular BSD variants. FreeBSD initially focused on PC hardware with Intel's 80386 processor. Simple installation is a goal of the project, so that even non-experts using this system is possible. Early on, the project therefore published installation CDs. In addition to Intel and AMD processors and other processors such as Sun SPARC and alpha are supported.

OpenBSD has as a major objective the development of the safest free system. This includes, for a proactive security, that is to be as far as possible error detected and eliminated in advance of code audits. But this means far from that in the other BSD security would be neglected. OpenBSD is a leader in the implementation of secure, encrypted transmission method. IPsec support is as important as an open implementation of the Secure Shell called OpenSSH.

Other BSD variants

BSD derivatives

  • Debian GNU / kFreeBSD, port of Debian GNU operating system to the FreeBSD kernel.
  • Debian GNU / NetBSD port of the Debian GNU operating system to the NetBSD kernel.
  • Darwin Stark modified FreeBSD derivative, and the basis for Mac OS X
  • Mac OS X Heavily modified, commercial FreeBSD derivative of Apple
Monolithic kernel BSD licenses History of Unix Network socket Remote Shell Daemon (computing) Sendmail UNIX System III MIPS architecture DEC Alpha BSD/OS William Jolitz Darwin (operating system) Comparison of BSD operating systems PC-BSD Marshall Kirk McKusick Groklaw Andrew S. Tanenbaum Integrated Authority File
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