Berkeley Software Distribution

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"BSD" redirects here. Berkeley Software Distribution_sentence_0

For the Windows error message abbreviated "BSOD" or "BSoD", see Blue Screen of Death. Berkeley Software Distribution_sentence_1

For other uses, see BSD (disambiguation). Berkeley Software Distribution_sentence_2

Berkeley Software Distribution_table_infobox_0

BSDBerkeley Software Distribution_table_caption_0
DeveloperBerkeley Software Distribution_header_cell_0_0_0 Computer Systems Research GroupBerkeley Software Distribution_cell_0_0_1
Written inBerkeley Software Distribution_header_cell_0_1_0 CBerkeley Software Distribution_cell_0_1_1
OS familyBerkeley Software Distribution_header_cell_0_2_0 UnixBerkeley Software Distribution_cell_0_2_1
Working stateBerkeley Software Distribution_header_cell_0_3_0 DiscontinuedBerkeley Software Distribution_cell_0_3_1
Source modelBerkeley Software Distribution_header_cell_0_4_0 Originally source-available, later open-sourceBerkeley Software Distribution_cell_0_4_1
Initial releaseBerkeley Software Distribution_header_cell_0_5_0 1977; 43 years ago (1977)Berkeley Software Distribution_cell_0_5_1
Latest releaseBerkeley Software Distribution_header_cell_0_6_0 4.4-Lite2 / 1995Berkeley Software Distribution_cell_0_6_1
Available inBerkeley Software Distribution_header_cell_0_7_0 EnglishBerkeley Software Distribution_cell_0_7_1
PlatformsBerkeley Software Distribution_header_cell_0_8_0 PDP-11, VAX, Intel 80386Berkeley Software Distribution_cell_0_8_1
Kernel typeBerkeley Software Distribution_header_cell_0_9_0 MonolithicBerkeley Software Distribution_cell_0_9_1
UserlandBerkeley Software Distribution_header_cell_0_10_0 BSDBerkeley Software Distribution_cell_0_10_1
Default user interfaceBerkeley Software Distribution_header_cell_0_11_0 Unix shellBerkeley Software Distribution_cell_0_11_1
LicenseBerkeley Software Distribution_header_cell_0_12_0 BSDBerkeley Software Distribution_cell_0_12_1

The Berkeley Software Distribution (BSD) is a discontinued operating system based on Research Unix, developed and distributed by the Computer Systems Research Group (CSRG) at the University of California, Berkeley. Berkeley Software Distribution_sentence_3

The term "BSD" commonly refers to its descendants, including FreeBSD, OpenBSD, NetBSD, and DragonFly BSD. Berkeley Software Distribution_sentence_4

BSD was initially called Berkeley Unix because it was based on the source code of the original Unix developed at Bell Labs. Berkeley Software Distribution_sentence_5

In the 1980s, BSD was widely adopted by workstation vendors in the form of proprietary Unix variants such as DEC Ultrix and Sun Microsystems SunOS due to its permissive licensing and familiarity to many technology company founders and engineers. Berkeley Software Distribution_sentence_6

Although these proprietary BSD derivatives were largely superseded in the 1990s by UNIX SVR4 and OSF/1, later releases provided the basis for several open-source operating systems including FreeBSD, OpenBSD, NetBSD, DragonFly BSD, Darwin, and TrueOS. Berkeley Software Distribution_sentence_7

These, in turn, have been used by proprietary operating systems, including Apple's macOS and iOS, which derived from them, and Microsoft Windows, which used (at least) part of its TCP/IP code, which was legal. Berkeley Software Distribution_sentence_8

Code from FreeBSD was also used to create the operating system for the PlayStation 4 and Nintendo Switch. Berkeley Software Distribution_sentence_9

History Berkeley Software Distribution_section_0

Main article: History of the Berkeley Software Distribution Berkeley Software Distribution_sentence_10

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. Berkeley Software Distribution_sentence_11

The operating system arrived at Berkeley in 1974, at the request of computer science professor Bob Fabry who had been on the program committee for the Symposium on Operating Systems Principles where Unix was first presented. Berkeley Software Distribution_sentence_12

A PDP-11/45 was bought to run the system, but for budgetary reasons, this machine was shared with the mathematics and statistics groups at Berkeley, who used RSTS, so that Unix only ran on the machine eight hours per day (sometimes during the day, sometimes during the night). Berkeley Software Distribution_sentence_13

A larger PDP-11/70 was installed at Berkeley the following year, using money from the Ingres database project. Berkeley Software Distribution_sentence_14

Understanding BSD requires delving far back into the history of Unix, the operating system first released by AT&T Bell Labs in 1969. Berkeley Software Distribution_sentence_15

BSD began life as a variant of Unix that programmers at the University of California at Berkeley, initially led by Bill Joy, began developing in the late 1970s. Berkeley Software Distribution_sentence_16

At first, BSD was not a clone of Unix, or even a substantially different version of it. Berkeley Software Distribution_sentence_17

It just included some extra utilities, which were intertwined with code owned by AT&T.If you use a free and open source operating system, it’s almost certainly based on the Linux kernel and GNU software. Berkeley Software Distribution_sentence_18

But these were not the first freely redistributable platforms, nor were they the most professional or widely commercialized. Berkeley Software Distribution_sentence_19

The Berkeley Software Distribution, or BSD, beat GNU/Linux on all of these counts. Berkeley Software Distribution_sentence_20

In 1975, Ken Thompson took a sabbatical from Bell Labs and came to Berkeley as a visiting professor. Berkeley Software Distribution_sentence_21

He helped to install Version 6 Unix and started working on a Pascal implementation for the system. Berkeley Software Distribution_sentence_22

Graduate students Chuck Haley and Bill Joy improved Thompson's Pascal and implemented an improved text editor, ex. Berkeley Software Distribution_sentence_23

Other universities became interested in the software at Berkeley, and so in 1977 Joy started compiling the first Berkeley Software Distribution (1BSD), which was released on March 9, 1978. Berkeley Software Distribution_sentence_24

1BSD was an add-on to Version 6 Unix rather than a complete operating system in its own right. Berkeley Software Distribution_sentence_25

Some thirty copies were sent out. Berkeley Software Distribution_sentence_26

The second Berkeley Software Distribution (2BSD), released in May 1979, 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. Berkeley Software Distribution_sentence_27

Some 75 copies of 2BSD were sent out by Bill Joy. Berkeley Software Distribution_sentence_28

A VAX computer was installed at Berkeley in 1978, but the port of Unix to the VAX architecture, UNIX/32V, did not take advantage of the VAX's virtual memory capabilities. Berkeley Software Distribution_sentence_29

The kernel of 32V was largely rewritten to include Berkeley graduate student Ozalp Babaoglu's virtual memory implementation, and a complete operating system including the new kernel, ports of the 2BSD utilities to the VAX, and the utilities from 32V was released as 3BSD at the end of 1979. Berkeley Software Distribution_sentence_30

3BSD was also alternatively called Virtual VAX/UNIX or VMUNIX (for Virtual Memory Unix), and BSD kernel images were normally called /vmunix until 4.4BSD. Berkeley Software Distribution_sentence_31

After 4.3BSD was released in June 1986, it was determined that BSD would move away from the aging VAX platform. Berkeley Software Distribution_sentence_32

The Power 6/32 platform (codenamed "Tahoe") developed by Computer Consoles Inc. seemed promising at the time, but was abandoned by its developers shortly thereafter. Berkeley Software Distribution_sentence_33

Nonetheless, the 4.3BSD-Tahoe port (June 1988) proved valuable, as it led to a separation of machine-dependent and machine-independent code in BSD which would improve the system's future portability. Berkeley Software Distribution_sentence_34

In addition to portability, the CSRG worked on an implementation of the OSI network protocol stack, improvements to the kernel virtual memory system and (with Van Jacobson of LBL) new TCP/IP algorithms to accommodate the growth of the Internet. Berkeley Software Distribution_sentence_35

Until then, all versions of BSD used proprietary AT&T Unix code, and were therefore subject to an AT&T software license. Berkeley Software Distribution_sentence_36

Source code licenses had become very expensive and several outside parties had expressed interest in a separate release of the networking code, which had been developed entirely outside AT&T and would not be subject to the licensing requirement. Berkeley Software Distribution_sentence_37

This led to Networking Release 1 (Net/1), which was made available to non-licensees of AT&T code and was freely redistributable under the terms of the BSD license. Berkeley Software Distribution_sentence_38

It was released in June 1989. Berkeley Software Distribution_sentence_39

After Net/1, BSD developer Keith Bostic proposed that more non-AT&T sections of the BSD system be released under the same license as Net/1. Berkeley Software Distribution_sentence_40

To this end, he started a project to reimplement most of the standard Unix utilities without using the AT&T code. Berkeley Software Distribution_sentence_41

Within eighteen months, all of the AT&T utilities had been replaced, and it was determined that only a few AT&T files remained in the kernel. Berkeley Software Distribution_sentence_42

These files were removed, and the result was the June 1991 release of Networking Release 2 (Net/2), a nearly complete operating system that was freely distributable. Berkeley Software Distribution_sentence_43

Net/2 was the basis for two separate ports of BSD to the Intel 80386 architecture: the free 386BSD by William Jolitz and the proprietary BSD/386 (later renamed BSD/OS) by Berkeley Software Design (BSDi). Berkeley Software Distribution_sentence_44

386BSD itself was short-lived, but became the initial code base of the NetBSD and FreeBSD projects that were started shortly thereafter. Berkeley Software Distribution_sentence_45

BSDi soon found itself in legal trouble with AT&T's Unix System Laboratories (USL) subsidiary, then the owners of the System V copyright and the Unix trademark. Berkeley Software Distribution_sentence_46

The USL v. BSDi lawsuit was filed in 1992 and led to an injunction on the distribution of Net/2 until the validity of USL's copyright claims on the source could be determined. Berkeley Software Distribution_sentence_47

The lawsuit slowed development of the free-software descendants of BSD for nearly two years while their legal status was in question, and as a result systems based on the Linux kernel, which did not have such legal ambiguity, gained greater support. Berkeley Software Distribution_sentence_48

The lawsuit was settled in January 1994, largely in Berkeley's favor. Berkeley Software Distribution_sentence_49

Of the 18,000 files in the Berkeley distribution, only three had to be removed and 70 modified to show USL copyright notices. Berkeley Software Distribution_sentence_50

A further condition of the settlement was that USL would not file further lawsuits against users and distributors of the Berkeley-owned code in the upcoming 4.4BSD release. Berkeley Software Distribution_sentence_51

The final release from Berkeley was 1995's 4.4BSD-Lite Release 2, after which the CSRG was dissolved and development of BSD at Berkeley ceased. Berkeley Software Distribution_sentence_52

Since then, several variants based directly or indirectly on 4.4BSD-Lite (such as FreeBSD, NetBSD, OpenBSD and DragonFly BSD) have been maintained. Berkeley Software Distribution_sentence_53

The permissive nature of the BSD license has allowed many other operating systems, both open-source and proprietary, to incorporate BSD source code. Berkeley Software Distribution_sentence_54

For example, Microsoft Windows used BSD code in its implementation of TCP/IP and bundles recompiled versions of BSD's command-line networking tools since Windows 2000. Berkeley Software Distribution_sentence_55

Darwin, the basis for Apple's macOS and iOS, is based on 4.4BSD-Lite2 and FreeBSD. Berkeley Software Distribution_sentence_56

Various commercial Unix operating systems, such as Solaris, also incorporate BSD code. Berkeley Software Distribution_sentence_57

Relationship to Research Unix Berkeley Software Distribution_section_1

Starting with the 8th Edition, versions of Research Unix at Bell Labs had a close relationship to BSD. Berkeley Software Distribution_sentence_58

This began when 4.1cBSD for the VAX was used as the basis for Research Unix 8th Edition. Berkeley Software Distribution_sentence_59

This continued in subsequent versions, such as the 9th Edition, which incorporated source code and improvements from 4.3BSD. Berkeley Software Distribution_sentence_60

The result was that these later versions of Research Unix were closer to BSD than they were to System V. In a Usenet posting from 2000, Dennis Ritchie described this relationship between BSD and Research Unix: Berkeley Software Distribution_sentence_61

Relationship to System V Berkeley Software Distribution_section_2

Eric S. Raymond summarizes the longstanding relationship between System V and BSD, stating, "The divide was roughly between longhairs and shorthairs; programmers and technical people tended to line up with Berkeley and BSD, more business-oriented types with AT&T and System V." Berkeley Software Distribution_sentence_62

In 1989, David A. Curry wrote about the differences between BSD and System V. He characterized System V as being often regarded as the "standard Unix." Berkeley Software Distribution_sentence_63

However, he described BSD as more popular among university and government computer centers, due to its advanced features and performance: Berkeley Software Distribution_sentence_64

Technology Berkeley Software Distribution_section_3

Berkeley sockets Berkeley Software Distribution_section_4

Berkeley's Unix was the first Unix to include libraries supporting the Internet Protocol stacks: Berkeley sockets. Berkeley Software Distribution_sentence_65

A Unix implementation of IP's predecessor, the ARPAnet's NCP, with and Telnet clients, had been produced at the University of Illinois in 1975, and was available at Berkeley. Berkeley Software Distribution_sentence_66

However, the memory scarcity on the PDP-11 forced a complicated design and performance problems. Berkeley Software Distribution_sentence_67

By integrating sockets with the Unix operating system's , it became almost as easy to read and write data across a network as it was to access a disk. Berkeley Software Distribution_sentence_68

The AT&T laboratory eventually released their own STREAMS library, which incorporated much of the same functionality in a software stack with a different architecture, but the wide distribution of the existing sockets library reduced the impact of the new API. Berkeley Software Distribution_sentence_69

Early versions of BSD were used to form Sun Microsystems' SunOS, founding the first wave of popular Unix workstations. Berkeley Software Distribution_sentence_70

Binary compatibility Berkeley Software Distribution_section_5

Some BSD operating systems can run much native software of several other operating systems on the same architecture, using a binary compatibility layer. Berkeley Software Distribution_sentence_71

Much simpler and faster than emulation, this allows, for instance, applications intended for Linux to be run at effectively full speed. Berkeley Software Distribution_sentence_72

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. Berkeley Software Distribution_sentence_73

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. Berkeley Software Distribution_sentence_74

Standards Berkeley Software Distribution_section_6

Current BSD operating system variants support many of the common IEEE, ANSI, ISO, and POSIX standards, while retaining most of the traditional BSD behavior. Berkeley Software Distribution_sentence_75

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. Berkeley Software Distribution_sentence_76

BSD descendants Berkeley Software Distribution_section_7

See also: Comparison of BSD operating systems Berkeley Software Distribution_sentence_77

Several operating systems are based on BSD, including FreeBSD, OpenBSD, NetBSD, MidnightBSD, GhostBSD, Darwin and DragonFly BSD. Berkeley Software Distribution_sentence_78

Both NetBSD and FreeBSD were created in 1993. Berkeley Software Distribution_sentence_79

They were initially derived from 386BSD (also known as "Jolix"), and merged the 4.4BSD-Lite source code in 1994. Berkeley Software Distribution_sentence_80

OpenBSD was forked from NetBSD in 1995, and DragonFly BSD was forked from FreeBSD in 2003. Berkeley Software Distribution_sentence_81

BSD was also used as the basis for several proprietary versions of Unix, such as Sun's SunOS, Sequent's DYNIX, NeXT's NeXTSTEP, DEC's Ultrix and OSF/1 AXP (now Tru64 UNIX). Berkeley Software Distribution_sentence_82

NeXTSTEP later became the foundation for Apple Inc.'s macOS. Berkeley Software Distribution_sentence_83

See also Berkeley Software Distribution_section_8

Berkeley Software Distribution_unordered_list_0

Credits to the contents of this page go to the authors of the corresponding Wikipedia page: Software Distribution.