It has been suggested that Traditional Unix be merged into this article or section. (Discuss)

The many divergents of System V

System V, previously known as AT&T System V and rarely called System 5, was one of the versions of the Unix computer operating system. It was originally developed by AT&T and first released in 1983. Four major versions of System V were released, termed Releases 1, 2, 3 and 4. System V Release 4, or SVR4, was the most successful version, and the source of several common Unix features, such as "SysV init scripts" (/etc/init.d), used to control system startup and shutdown. The system also forms the basis of the System V Interface Definition (SVID), a standard defining how System V systems should work. Image File history File links Please see the file description page for further information. ... Traditional Unix is a phrase used to descripe a Unix or GNU operating system that has the characteristics of either Version 7 Unix or UNIX System V. ... Image File history File links Download high resolution version (656x1359, 20 KB) PNG version of Image:UnixHistory. ... Image File history File links Download high resolution version (656x1359, 20 KB) PNG version of Image:UnixHistory. ... AT&T Inc. ... Wikibooks has more about this subject: Guide to UNIX Unix or UNIX is a computer operating system originally developed in the 1960s and 1970s by a group of AT&T Bell Labs employees including Ken Thompson, Dennis Ritchie, and Douglas McIlroy. ... An operating system is a program required for the user to manage the system and to run third-party application software for that system. ... 1983 (MCMLXXXIII) was a common year starting on Saturday of the Gregorian calendar. ... init is the program on Unix and Unix-like systems which spawns all other processes. ... The System V Interface Definition (or SVID) is a standard which describes the AT&T UNIX System V behavior, including that of system calls, C libraries, available programs and devices. ...

While AT&T sold their own hardware which ran System V (see AT&T Computer Systems), most customers ran a version from a reseller, based on AT&T's reference implementation. Popular SysV derivatives include Dell SVR4 and Bull SVR4. The most widely used versions of System V today are IBM's AIX and SCO OpenServer, based on System V Release 3, and Sun Microsystems Solaris Operating Environment and SCO UnixWare, both based on System V Release 4. AT&T Computer Systems is the generic name for AT&Ts abortive attempt to enter the computer business. ... In computing, a reference implementation (or, infrequently, sample implementation) is a software example of a standard for use in helping others implement their own versions of the standard. ... International Business Machines Corporation (IBM, or colloquially, Big Blue) NYSE: IBM (incorporated June 15, 1911, in operation since 1888) is headquartered in Armonk, NY, USA. The company manufactures and sells computer hardware, software, infrastructure services and consulting services. ... AIX (Advanced Interactive eXecutive) is a proprietary operating system developed by IBM based on UNIX System V. Before the product was ever marketed, the acronym AIX originally stood for Advanced IBM Unix. ... SCO OpenServer, previously SCO UNIX and SCO ODT, is a Unix-like computer operating system developed by Santa Cruz Operation (SCO) and now maintained by the SCO Group. ... Sun Microsystems, Inc. ... This article or section contains information that has not been verified and thus might not be reliable. ... UnixWare is a flavor of the Unix operating system. ...

System V was an enhancement over AT&T's first commercial UNIX called System III (System IV was an AT&T-internal version). Traditionally, System V has been considered one of the two major "flavors" of UNIX, the other being BSD. However, with the advent of UNIX implementations developed from neither code base, such as Linux and QNX, this generalisation is not as accurate as it once was, and in any case standardisation efforts such as POSIX are tending to reduce the differences between implementations. System III was a version of the Unix operating system released by AT&Ts Unix System Group (USG). ... BSD redirects here; for other uses see BSD (disambiguation). ... Tux is the official Linux mascot. ... QNX (pronounced either Q-N-X or Q-nix) is a commercial POSIX-compliant Unix-like real-time operating system, aimed primarily at the embedded systems market. ... POSIX is the collective name of a family of related standards specified by the IEEE to define the application programming interface (API) for software compatible with variants of the Unix OS. They are formally designated as IEEE 1003 and the international standard name is ISO/IEC 9945. ...

During the period of the Unix wars System V was known for being the primary choice of manufacturers of large multiuser systems, in opposition to BSD's dominance of desktop workstations. The Unix wars were the struggles between vendors of the Unix computer operating system in the late 1980s and early 1990s to set the standard for Unix henceforth. ... BSD redirects here; for other uses see BSD (disambiguation). ...

SVR1

The first version of System V was released in 1983. It was based on System III and the Bell Labs internal UNIX/TS 5.0, and also included features such as the vi editor and curses from the Berkeley Software Distribution of UNIX developed at the University of California, Berkeley (UCB). System V ran on the DEC VAX machine. It also added support for inter-process communication using messages, semaphores, and shared memory. The correct title of this article is vi. ... Curses is a terminal control library for UNIX-like systems, enabling the construction of text user interface (TUI) applications. ... Berkeley Software Distribution (BSD, sometimes called Berkeley Unix) is the Unix derivative distributed by the University of California, Berkeley starting in the 1970s. ... University of California, Berkeley The University of California, Berkeley (also known as California, Cal, UCB, UC Berkeley, The University of California, or simply Berkeley) is a public, coeducational university situated east of the San Francisco Bay in Berkeley, California, overlooking the Golden Gate. ... VAX is a 32-bit computing architecture that supports an orthogonal instruction set (machine language) and virtual addressing (i. ... The expression Inter-process communication (IPC) describes the exchange of data between one process and another, either within the same computer or over a network. ... A semaphore is a protected variable (or abstract data type) and constitutes the classic method for restricting access to shared resources (e. ... Shared memory refers to a (typically) large block of Random access memory that can be accessed by several different central processing units (CPUs) in a multiple-processor computer system. ...

SVR2

System V Release 2 was released in 1984. It added UNIX shell functions and the SVID. The concept of the "porting base" was formalized, and the DEC VAX 11/780 was named for this Release. The "porting base" is the so-called original version of a Release, from which all porting efforts for other machines emanate. A Unix shell, also called the command line, provides the traditional user interface for the Unix operating system. ... The System V Interface Definition (or SVID) is a standard which describes the AT&T UNIX System V behavior, including that of system calls, C libraries, available programs and devices. ...

SVR3

System V Release 3 was released in 1987. It included STREAMS, remote file sharing (RFS), shared libraries, and the Transport Layer Interface (TLI). The AT&T 3B2 became the official "porting base". STREAMS is the Unix System V networking architecture. ... In computer science, a library is a collection of subprograms used to develop software. ... In computer software, specifically networking, the Transport Layer Interface (TLI) was the networking API provided by AT&T UNIX System V Release 3. ...

SVR4

System V Release 4.0 was announced on November 1, 1989 and was released in 1990. A joint project of UNIX Systems Laboratories and Sun Microsystems, it combined technology from Release 3 as well as 4.3BSD, Xenix, and SunOS: November 1 is the 305th day of the year (306th in leap years) in the Gregorian Calendar, with 60 days remaining. ... 1989 (MCMLXXXIX) was a common year starting on Sunday of the Gregorian calendar. ... This article is about the year. ... UNIX Systems Laboratories or USL was originally organized as part of Bell Labs in 1989. ... Sun Microsystems, Inc. ... Berkeley Software Distribution (BSD, sometimes called Berkeley Unix) is the Unix derivative distributed by the University of California, Berkeley starting in the 1970s. ... Xenix was a Unix-like computer operating system derived from the UNIX system developed by Microsoft in the 1980s. ... SunOS was the version of the UNIX operating system developed by Sun Microsystems for their workstations and server systems until the early 1990s. ...

• From BSD: TCP/IP support, csh
• From SunOS: the Virtual file system interface (replacing the one in System V release 3, the "File System Switch"), Network File System (NFS), new virtual memory system including support for memory mapped files, a new shared library system
• Other improvements:
  • ksh
  • ANSI C compatibility
  • better internationalization support
  • an application binary interface (ABI)
  • support for standards such as POSIX, X/Open, and SVID3

The Internet protocol suite is the set of communications protocols that implement the protocol stack on which the Internet runs. ... The C shell (csh) is a Unix shell developed by Bill Joy for the BSD Unix system. ... A Virtual file system or Virtual filesystem switch (VFS) is an abstraction layer on top of a more concrete file system. ... Network File System (NFS) is a protocol originally developed by Sun Microsystems in 1984 and defined in RFCs 1094, 1813, and 3530 (obsoletes 3010), as a distributed file system which allows a computer to access files over a network as easily as if they were on its local disks. ... In computing, mmap() is a POSIX-compliant Unix system call that maps files or devices into memory. ... Korn shell logo. ... The C Programming Language, Brian Kernighan and Dennis Ritchie, the original edition that served for many years as an informal specification of the language The C programming language is a standardized imperative computer programming language developed in the early 1970s by Dennis Ritchie for use on the Unix operating system. ... It has been suggested that Software localization be merged into this article or section. ... In computer software, an application binary interface (ABI) describes the low-level interface between an application program and the operating system, between an application and its libraries, or between component parts of the application. ... POSIX is the collective name of a family of related standards specified by the IEEE to define the application programming interface (API) for software compatible with variants of the Unix OS. They are formally designated as IEEE 1003 and the international standard name is ISO/IEC 9945. ... X/Open Company, Ltd. ...

SVR4.1

Release 4.1 added asynchronous I/O.

SVR4.2

Release 4.2 added support for the Veritas filesystem, access control lists (ACLs), and dynamically loadable kernel modules. This codebase, in greatly modified form, is available as open source in the form of Sun's OpenSolaris project. The access control list (ACL) is a concept in computer security used to enforce privilege separation. ... A module is a self-contained component of a system, which has a well-defined interface to the other components; something is modular if it is constructed so as to facilitate easy assembly, flexible arrangement, and/or repair of the components. ... Open source refers to projects that are open to the public and which draw on other projects that are freely available to the general public. ... OpenSolaris is an open source project created by Sun Microsystems to build a developer community around the Solaris Operating System technology. ...

Note: this is not correct. Solaris diverged from SVR4.0. USL/Novell continued to enhance SVR4 and licensed the later releases to other vendors.

SVR5

Release 5 was released as SCO UnixWare 7 by The SCO Group. The codebase is not used by any other manufacturer. UnixWare is a flavor of the Unix operating system. ... The SCO Group, Inc. ...

External links

• Unix FAQ - history