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 initscripts" (/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 DellSVR4 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 Systemand 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-likesystems developed from neither code base, such as Linuxand QNX, this generalization is not as accurate as it once was, and in any case standardisation efforts such as POSIXare tending to reduce the differences between implementations.
During the period of the
Unix warsSystem V was known for being the primary choice of manufacturers of large multiuser systems, in opposition to BSD's dominance of desktop workstations.
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
vieditor and curses from the Berkeley Software Distributionof UNIX developed at the University of California, Berkeley(UCB); it also improved performance by adding buffer and inodecaches. System V ran on the DEC VAXand PDP-11machines. It also added support for inter-process communicationusing messages, semaphores, and shared memory.
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
authorlink = Berny Goodheart
title=The Magic Garden Explained
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
title=The Design of the UNIX Operating System
id=ISBN 0-13-201799-7] is the definitive description of the System V Release 2 kernel.
Apple Computer's A/UXoperating 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-UXwas also an SVR2 derivative. [Rosen, p. 33.]
System V Release 3 was released in 1987. It included
STREAMS, the Remote File System(RFS), the File System Switch (FSS) virtual file systemmechanism, 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 systemis an SVR3 derivative.
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
accessdate= 2007-01-01 ] and was released in
1990.Fact|date=February 2007 A joint project of Unix System Laboratoriesand Sun Microsystems, it combined technology from Release 3 as well as 4.3BSD, Xenix, and SunOS:
TCP/IPsupport, sockets, ufs, support for multiple groups, csh
*From SunOS: the
virtual file systeminterface (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 GUIenvironment, 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)
**ANSI X3J11 C compatibility
**Multi-National Language Support (MNLS)
**better internationalization support
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, SunOS5.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 OpenSolarisproject, 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 Amigaas Amiga Unixand Atarias ASV SVR4 Unix1991.
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.
Release 4.1 added
asynchronous I/O.Fact|date=January 2008
Release 4.2, developed in
1992added 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) UnixWare1, UHC UnixWare, and Consensys.
Release 4.2MP, completed late
1993, added support for multiprocessing. It was released as UnixWare 2 in 1995.Fact|date=January 2008
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 Groupalso based SCO OpenServer6 on SVR5, but the codebase is not used by any other manufacturer.Fact|date=January 2008
* [http://www.catb.org/~esr/faqs/clone-unix-guide.txt PC-clone UNIX Software Buyer's Guide] by
Eric S. Raymond(posted to USENETin 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
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
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