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The term Unices includes Unix and Unix-like operating systems. Unices is the plural of Unix. (Strictly speaking, the form Unices is a spurious plural, since Unix is not a Latin word. Tongue-in-cheek plurals like this are however popular in computer jargon.)
As is often the case with developments that go on to become highly popular and influential, the beginnings of UNIX are unremarkable.
In the late 1960s, the Massachusetts Institute of Technology, AT&T Bell Labs, and General Electric worked on an experimental operating system called Multics (Multiplexed Information and Computing System), which was designed to run on the GE-645 mainframe computerMainframes (often colloquially referred to as "big iron") are large, powerful, and expensive computers used mainly by government institutions and large companies for bulk data processing (such as censuses, industry/consumer statistics, ERP, and bank trans. The aim was the creation of an interactive operating system with many novel capabilities, including enhanced securitySecurity is being free from danger. In absolute sense this is hardly possible, it is a relative matter. The term can be used with reference to crime, accidents of all kinds, etc. Note that Security should not be confused with Safety. In some languages (e.. The project did develop production releases, but initially these releases turned out to have poor performance.
AT&T Bell Labs pulled out and deployed its resources elsewhere. One of the developers on the Bell Labs team, Ken Thompson, continued to develop for the GE-645 mainframe, and wrote a game for the computer called Space Travel. However he found that the game was slow on the GE machine and was costly, apparently costing $75 per go.
Thompson thus re-wrote the game with help from Dennis Ritchie to run on the DECDigital Equipment Corporation is a pioneering company in the American computer industry. They are generally referred to within the computing industry as DEC . This acronym was once officially used by DEC itself Digital Equipment Corporation#References|[1] PDP-7The DEC PDP-7 is a minicomputer produced by Digital Equipment Corporation. Introduced in 1965, the first to use their Flip Chip® technology, with a cost of only US-$ 72,000, this computer was very cheap, but quite powerful. The PDP-7 is an 18-bit architec, written in PDP-7 Assembly languageAssembly language or simply assembly is a human-readable notation for the machine language that a specific computer architecture uses. Machine language, a pattern of bits encoding machine operations, is made readable by replacing the raw values with symbo. This experience, combined with his work on the Multics project, led Thompson to start a new operating system for the DEC PDP-7. Thompson and Ritchie led a team of developers, including Rudd Canaday , at Bell Labs developing a file systemSee Filing system for this term as it is used in libraries and offices In computing, a file system is a method for storing and organizing computer files and the data they contain to make it easy to find and access them. File systems may use a storage devi as well as the new multi-tasking operating system itself. They included a command interpreterA command line interpreter is a computer program which reads a line of text the user has typed and interprets this text in the context of a given operating system or programming language. Command line interpreters have the advantage that the user may issu and some small utility programs as well. This project was called UNICS, short for Uniplexed Information and Computing System, because it could support two simultaneous users. The name has been attributed to Brian Kernighan, and was a hack on Multics. Following bad puns of UNICS ( homophone of eunuchs) being a castrated MULTICS, the name was later changed to UNIX, and thus a legacy was born.
Up until this point there had been no financial support from Bell Labs, when the Computer Science Research Group wanted to use UNIX on a much larger machine than the PDP-7. Thompson and Ritchie managed to trade the promise of adding text processing capabilities to UNIX for a PDP-11/20 machine, and this itself led to some financial support from Bell. For the first time in 1970, the UNIX Operating System was officially named and ran on the PDP-11/20. It added a text formatting program called roff and a text editor. All three were written in the PDP-11/20 assembly language. This initial "text processing system", made up of UNIX, roff and the editor, was used by Bell Labs for text processing of patent applications at Bell. Runoff soon evolved into troff, the first electronic publishing program with a full typesetting capability. The UNIX Programmer's Manual was published on November 3, 1971.
In 1973 the decision was made to re-write UNIX in the C programming language. The change meant that UNIX could later easily be modified to work on other machines (thus becoming portable), and other variations could be created by other developers. The code was now more concise and compact, leading to an acceleration in the development of UNIX. AT&T made UNIX available to universities and commercial firms, as well as the United States government under licenses.
Development expanded, with Versions 4, 5 and 6 being released by 1975. These versions added pipes, leading to the development of a more modular code-base, increasing development speed still further. By 1978 over 600 machines were running UNIX in some form. Version 7, the last version of Research UNIX to be released widely, was released in 1979. Versions 8, 9 and 10 were developed through the 1980s but were only ever released to a few universities, though they did generate papers describing the new work. This research led to the development of Plan 9, a new portable distributed system, now available at http://plan9.bell-labs.com/plan9dist/.
AT&T now developed UNIX System III , based on Version 7, as a commercial version and sold the product directly, the first version launching in 1982. However its subsidiary, Western Electric, continued to sell older UNIX versions, based on the UNIX System (Versions 1 to 7). To end the confusion between all the differing versions, AT&T combined various versions developed at other universities and companies into UNIX System V Release 1. This introduced features such as the Vi editor and curses from the Berkeley Software Distribution of UNIX developed at the University of California, Berkeley (UCB). This also included support for the DEC VAX machine.
The new commercial UNIX releases however no longer included the source code and so UCB continued to develop BSD UNIX as an alternative to UNIX System III and V, originally on the PDP-11 architecture (the BSD 2.x releases, ending with 2.10). Perhaps the most important aspect of the BSD development effort was the addition of TCP/IP network code to the mainstream UNIX kernel. The BSD effort produced 8 significant releases that contained network code: 4.1c, 4.2, 4.3, 4.3-Tahoe ("Tahoe" being the nickname of the CCI Power 6/32 architecture that was the first non-DEC port of the BSD kernel), 4.3-Reno (to match the "Tahoe" naming, and that the release was something of a gamble), Net2, 4.4, and 4.4-lite. The network code found in these releases is the ancestor of almost all TCP/IP network code in use today, including code that was later released in AT&T System V UNIX and Microsoft Windows.
Other companies began to offer commercial version of the UNIX System for their own mini-computers and workstations. Most of these new UNIX flavors were developed from the System V base under a license from AT&T. Others chose BSD instead. One of the leading developers of BSD, Bill Joy, went on to create SunOS, and eventually co-founding Sun Microsystems to distribute the operating system.
In 1991, a group of BSD's developers ( Donn Seeley , Mike Karels , Bill Jolitz , and Trent Hein ) left the University of California to found Berkeley Software Design, Inc ( BSDI ). BSDI was the first company to produce a fully-functional commercial version of BSD UNIX for the inexpensive and ubiquitous Intel platform, which started a wave of interest in the use of inexpensive hardware for production computing. Shortly after it was founded, Bill Jolitz left BSDI to pursue distribution of 386BSD, commonly identified as the freeware ancestor of FreeBSD, OpenBSD, and NetBSD.
AT&T added features such as file locking , system administration, job control , streams , the Remote File System and TLI into UNIX System V. However AT&T decided in 1987-1989 to merge Xenix (Microsoft's development of UNIX for x86-PC's, announced on August 25 1980), BSD, SunOS and System V into System V Release 4 (SVR4). This new release solidified all the previous features into one package, and spelled the end of competing versions.
By 1993 most of the commercial vendors of UNIX had changed their commercial variants of UNIX to be based upon SVR4, and many BSD features were added on top.
Shortly after UNIX System V Release 4 was produced AT&T sold all its rights to UNIX to Novell. Dennis Ritchie, one of the creators of UNIX likened this to the Biblical story of Esau selling his birthright for some lentils [1]. Novell developed its own version, UNIXware , merging its Netware with UNIX System V Release 4. Novell tried to use this to battle against Microsoft Windows NT, but their core markets suffered considerably.
In 1994, Novell decided to split the bundle of UNIX related assests and sell parts of them. The UNIX trademark and the certification rights were sold to the X/Open Consortium, which was an industry group to define a "UNIX Standard". Finally X/OPEN and OSF/1 (a competitor to the SVR4 standardisation) merged, creating the Open Group. Various standards by the Open Group now define what is and what isn't a "UNIX" operating system.
In 1995, the business of administration and support of the existing UNIX licenses plus rights to further develop the SystemV code base were transferred to the Santa Cruz Operation, (SCO). And Novell retained the core copyrights, veto rights over future licensing activities of SCO, and 95% of the licensing revenue.
In 2000, the Santa Cruz Operation sold its entire UNIX business and assets to Caldera Systems, which later on changed its name to The SCO Group. This new player then started a huge legal campaign against various users and vendors of Linux. The SCO Group has offered various legal theories over the course of several cases. Some of these allege that Linux contains copyrighted Unix code now owned by The SCO Group. Others allege trade-secret violations by IBM, or contract violations by former Santa Cruz customers who since converted to Linux. The most far reaching theory is that development work that IBM did for AIX is considered a derivative work and therefore also owned by SCO. If this is upheld it would affect all Unix licensees.
Under a program called SCOsource, the SCO Group is now offering licenses to all companies and individuals wishing to use operating systems with code based on UNIX System V Release 4 (and their own release, UNIX System V, Release 5).
However, Novell dispute the SCO group's claim to hold copyright on the UNIX source base. According to Novell, SCO (and hence the SCO group) are effectively franchise operators for Novell. The SCO Group disagree with this, and the dispute has resulted in the SCO v. Novell lawsuit.
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