UNIX System V

Unix System V, commonly abbreviated SysV (and usually pronounced, though rarely written as System 5), was one of the versions of the Unix 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.

While AT&T sold their own hardware that 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, based on System V Release 3, and Sun Microsystems' Solaris Operating System and HP's HP-UX, both based on System V Release 4.

System V was an enhancement over AT&T's first commercial Unix called System III (there was never an outside release of System IV ["Whatever happened to System IV is one of the great unsolved mysteries of computer science." Andrew S. Tanenbaum (2001). "Modern Operating Systems". Upper Saddle River, NJ: Prentice Hall, p. 675.] ). Traditionally, System V has been considered one of the two major "flavors" of UNIX, the other being BSD. However, with the advent of Unix-like systems developed from neither code base, such as Linux and QNX, this generalization 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.

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.

VR1

The first version of System V (also called System V.0 or System V Release 1, SVR1) was released in 1983. Developed by AT&T's Unix System Development Labs (USDL), a merger of the Unix Support Group and the PWB group, it was based on System III and the Bell Labs internal UNIX/TS 5.0. System V 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); it also improved performance by adding buffer and inode caches. System V ran on the DEC VAX and PDP-11 machines. It also added support for inter-process communication using messages, semaphores, and shared memory.

VR2

System V Release 2 was released in 1984. It added shell functions and the SVID. New kernel features included record and file locking, demand paging, and copy on write. [cite book
last=Goodheart
first=Berny
authorlink = Berny Goodheart
coauthors=James Cox
title=The Magic Garden Explained
publisher=Prentice Hall
year=1994
pages=11
id=ISBN 0-13-098138-9
] 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. Maurice J. Bach's "The Design of the UNIX Operating System" [cite book
last=Bach
first=Maurice
title=The Design of the UNIX Operating System
publisher=Prentice Hall
year=1986
id=ISBN 0-13-201799-7
] is the definitive description of the System V Release 2 kernel.

Apple Computer's A/UX operating system was based on this release (later versions had many extensions from SVR3, SVR4, and BSD), although it was heavily integrated with the Macintosh Toolbox. The first release of HP-UX was also an SVR2 derivative. [Rosen, p. 33.]

VR3

System V Release 3 was released in 1987. It included STREAMS, the Remote File System (RFS), the File System Switch (FSS) virtual file system mechanism, a restricted form of shared libraries, and the Transport Layer Interface (TLI) network API. The final version was Release 3.2 in 1988, which added binary compatibility to Xenix on Intel platforms; SCO Xenix System V/386 was based upon 3.2. The AT&T 3B2 became the official "porting base". IBM's AIX operating system is an SVR3 derivative.

VR4

System V Release 4.0 was announced on October 18, 1988 [cite press release
title= SEVERAL MAJOR COMPUTER AND SOFTWARE COMPANIES ANNOUNCE STRATEGIC COMMITMENT TO AT&T'S UNIX SYSTEM V, RELEASE 4.0
publisher= Amdahl, Control Data Corporation, et al
date= October 18, 1988
url= http://groups.google.com/group/comp.unix.questions/msg/2e02a599c5c62848
accessdate= 2007-01-01
] and was released in 1990.Fact|date=February 2007 A joint project of Unix System Laboratories and Sun Microsystems, it combined technology from Release 3 as well as 4.3BSD, Xenix, and SunOS:
*From BSD: TCP/IP support, sockets, ufs, support for multiple groups, 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, an improved shared library system based on the SunOS 4.x model, the OpenWindows GUI environment, External Data Representation (XDR) and Remote Procedure Calls (RPC)
*From Xenix: x86 device drivers, binary compatibility with Xenix (in the x86 version of System V)
*Other improvements:
**ksh
**ANSI X3J11 C compatibility
**Multi-National Language Support (MNLS)
**better internationalization support
**an application binary interface (ABI)
**support for standards such as POSIX, X/Open, and SVID3

The primary platforms for SVR4 were Intel x86 and SPARC; the SPARC version, called Solaris 2 (or, internally, SunOS 5.x), was developed by Sun. The relationship between Sun and AT&T was terminated after the release of SVR4, meaning that later versions of Solaris did not inherit features of later SVR4.x releases. Sun would in 2005 release most of the source code for Solaris 10 (SunOS 5.10) as the open source OpenSolaris project, creating the only open-source (heavily modified) System V implementation available.

Many versions of SVR4 appeared, because of hardware vendors (HP, SGI) adapting it to their platform, and because porting houses (SCO, Microport, ESIX, UHC) sold enhanced and supported x86 versions. SVR4 was even ported to the Amiga as Amiga Unix and Atari as ASV SVR4 Unix 1991.

VR4.0MP

Built by a consortium of Intel based resellers (including Unisys, ICL and NCR Corporation).Fact|date=January 2008 It provided a limited multi-processor capability. This allowed operating system calls to be processed from any processor, but interrupt servicing only from a "master" processor.

VR4.1

Release 4.1 added asynchronous I/O.Fact|date=January 2008

VR4.2

Release 4.2, developed in 1992 added support for the Veritas filesystem, access control lists (ACLs), and dynamically loadable kernel modules.Fact|date=January 2008

Again, several versions of SVR4.2 appeared, including Univel (later SCO) UnixWare 1, UHC UnixWare, and Consensys.

VR4.2MP

Release 4.2MP, completed late 1993, added support for multiprocessing. It was released as UnixWare 2 in 1995.Fact|date=January 2008

VR5

System V Release 5 was developed in 1997 by the Santa Cruz Operation (SCO) as a merger of SCO OpenServer (an SVR3-derivative) and UnixWare, with a focus on large-scale servers. [Kenneth H. Rosen (1999). "UNIX: The Complete Reference". McGraw-Hill Professional, pp. 23, 32.] It was released as SCO UnixWare 7. SCO's successor, The SCO Group also based SCO OpenServer 6 on SVR5, but the codebase is not used by any other manufacturer.Fact|date=January 2008

References

External links

* [http://www.catb.org/~esr/faqs/clone-unix-guide.txt PC-clone UNIX Software Buyer's Guide] by Eric S. Raymond (posted to USENET in 1994)
* [http://www.faqs.org/faqs/unix-faq/faq/part6/ Unix FAQ - history]
* [http://www.levenez.com/unix/ A Unix History Diagram] - The original and continuously updated version of the Unix history, as published by O'Reilly


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • UNIX System V — UNIX System V, ou System V (soit « système cinq », 5 étant écrit en chiffre romain) est une version du système d exploitation d origine UNIX, dévoilée par l entreprise AT T en janvier 1983. System V est une version majeure d UNIX, avec… …   Wikipédia en Français

  • UNIX System V — Множество потомков System V …   Википедия

  • Unix System V — Множество потомков System V AT T UNIX System V одна из версий операционной системы 1989 г. Было выпущено 4 основные версии Releases 1, 2, 3 и 4. Версия System V Release 4 (SVR4) была наиболее удачной и популярной и послужила источником для… …   Википедия

  • UNIX System V — System V ist der Name einer Version des Unix Betriebssystems von AT T und wurde erstmals 1983 als Nachfolger von System III veröffentlicht. Seit 1992 liegt es in der Version System V Release 4.2 vor. Inhaltsverzeichnis 1 Überblick 2 Neuerungen 3… …   Deutsch Wikipedia

  • UNIX system — noun trademark for a powerful operating system • Syn: ↑UNIX, ↑UNIX operating system • Hypernyms: ↑operating system, ↑OS • Instance Hyponyms: ↑Linux …   Useful english dictionary

  • UNIX System Services — (USS) is a required, included component of z/OS. USS is a certified UNIX implementation (XPG4 UNIX 95) optimized for mainframe architecture. It is the first UNIX 95 to not be derived from the AT T source code. Through integration with the rest of …   Wikipedia

  • Unix System Services — (USS) ist eine Komponente des z/OS. USS ist eine vollwertige, zertifizierte Unix Implementierung (XPG4 UNIX 95). Es handelt sich um das erste Unix 95, welches nicht aus dem AT T / SCO Sourcecode abgeleitet wurde. Durch die Integration in z/OS… …   Deutsch Wikipedia

  • Unix System Laboratories — or USL was originally organized as part of Bell Labs in 1989. USL joined with the UNIX Software Operation, also a Bell Laboratories division, in 1990. It assumed responsibility for Unix development and licensing activities. It then became a… …   Wikipedia

  • UNIX System Services — ou USS est un sous système de MVS permettant de faire fonctionner des programmes dans un environnement UNIX. Il possède un Shell basé sur Korn. Appelé OpenEdition sous OS/390, il change de nom en 2001 pour UNIX System Services. USS est certifié… …   Wikipédia en Français

  • UNIX System III — Bell Unices Research Unix V6 (1975) V7 (1979) V8 (1985) V9 (1986) V10 (1989) Другие CB UNIX (c. 1975) PWB/UNIX (1977) System III (1982) Syste …   Википедия

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.