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Encyclopedia > Unix
Filiation of Unix and Unix-like systems
Filiation of Unix and Unix-like systems

Unix (officially trademarked as UNIX®, sometimes also written as Unix or Unix® with small caps) is a computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs including Ken Thompson, Dennis Ritchie and Douglas McIlroy. Today's Unix systems are split into various branches, developed over time by AT&T as well as various commercial vendors and non-profit organizations. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... In typography, small caps (short for small capitals) are uppercase (capital) characters that are printed in a smaller size than normal uppercase characters of the same font. ... An operating system (OS) is a software that manages computer resources and provides programmers with an interface used to access those resources. ... This article is about the current AT&T. For the 1885-2005 company, see American Telephone & Telegraph. ... Bell Laboratories (also known as Bell Labs and formerly known as AT&T Bell Laboratories and Bell Telephone Laboratories) was the main research and development arm of the United States Bell System. ... Ken Thompson Kenneth Thompson (born February 4, 1943) is a pioneer of computer science notable for his contributions to the development of the C programming language and the UNIX operating system. ... Dennis Ritchie Dennis MacAlistair Ritchie (born September 9, 1941) is a computer scientist notable for his influence on ALTRAN, B, BCPL, C, Multics, and Unix. ... Portrait of Douglas McIlroy taken at the NATO conference in Garmisch 1968, courtesy of Brian Randell. ...


As of 2007, the owner of the trademark UNIX® is The Open Group, an industry standards consortium. Only systems fully compliant with and certified to the Single UNIX Specification qualify as "UNIX®" (others are called "Unix system-like" or "Unix-like"). “(TM)” redirects here. ... This article or section reads like an advertisement. ... The Single UNIX Specification (SUS) is the collective name of a family of standards for computer operating systems to qualify for the name Unix. The SUS is developed and maintained by the Austin Group, based on earlier work by the IEEE and The Open Group. ... Diagram of the relationships between several Unix-like systems A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification. ...


During the late 1970s and early 1980s, the influence of Unix in academic circles led to large-scale adoption of Unix (particularly of the BSD variant, originating from the University of California, Berkeley) by commercial startups, the most notable of which is Sun Microsystems. Today, in addition to certified Unix systems, Unix-like operating systems such as Linux and BSD are commonly encountered. Sometimes, "traditional Unix" may be used to describe a Unix or an operating system that has the characteristics of either Version 7 Unix or UNIX System V. BSD redirects here. ... Sather Tower (the Campanile) looking out over the San Francisco Bay and Mount Tamalpais. ... Sun Microsystems, Inc. ... Diagram of the relationships between several Unix-like systems A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification. ... This article is about operating systems that use the Linux kernel. ... BSD redirects here. ... Seventh Edition Unix, also called Version 7 Unix, Version 7 or just V7, was an important early release of the Unix operating system. ... It has been suggested that Traditional Unix be merged into this article or section. ...

Contents

Overview

Unix operating systems are widely used in both servers and workstations. The Unix environment and the client-server program model were essential elements in the development of the Internet and the reshaping of computing as centered in networks rather than in individual computers. In information technology, a server is an application or device that performs services for connected clients as part of a client-server architecture. ... Sun SPARCstation 1+, 25 MHz RISC processor from early 1990s A workstation, such as a Unix workstation, RISC workstation or engineering workstation, is a high-end desktop or deskside microcomputer designed for technical applications. ... Client/Server is a network application architecture which separates the client (usually the graphical user interface) from the server. ... This article or section is in need of attention from an expert on the subject. ...


Both Unix and the C programming language were developed by AT&T and distributed to government and academic institutions, causing both to be ported to a wider variety of machine families than any other operating system. As a result, Unix became synonymous with "open systems". C is a general-purpose, block structured, procedural, imperative computer programming language developed in 1972 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system. ... Open systems are computer systems that provide either interoperability, portability, or freedom from proprietary standards, depending on users perspective. ...


Unix was designed to be portable, multi-tasking and multi-user in a time-sharing configuration. Unix systems are characterized by various concepts: the use of plain text for storing data; a hierarchical file system; treating devices and certain types of inter-process communication (IPC) as files; and the use of a large number of software tools, small programs that can be strung together through a command line interpreter using pipes, as opposed to using a single monolithic program that includes all of the same functionality. These concepts are known as the Unix philosophy. In computer science, porting is the process of adapting software so that an executable program can be created for a computing environment that is different from the one for which it was originally designed (e. ... In computing, multitasking is a method by which multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is... Multi-user is a term that defines an operating system that allows concurrent access by multiple users of a computer. ... Alternate uses: see Timesharing Time-sharing is an approach to interactive computing in which a single computer is used to provide apparently simultaneous interactive general-purpose computing to multiple users by sharing processor time. ... Computer files can be divided into two broad categories: binary and text. ... For library and office filing systems, see Library classification. ... Inter-Process Communication (IPC) is a set of techniques for the exchange of data between two or more threads in one or more processes. ... A programming tool is a program or application that software developers use to create, debug, or maintain other programs and applications. ... It has been suggested that this article or section be merged into Command line interface. ... A pipeline of three programs run on a text terminal In Unix-like computer operating systems, a pipeline is the original software pipeline: a set of processes chained by their standard streams, so that the output of each process (stdout) feeds directly as input (stdin) of the next one. ... The Unix philosophy is a set of cultural norms and philosophical approaches to developing software based on the experience of leading developers of the Unix operating system. ...


Under Unix, the "operating system" consists of many of these utilities along with the master control program, the kernel. The kernel provides services to start and stop programs, handle the file system and other common "low level" tasks that most programs share, and, perhaps most importantly, schedules access to hardware to avoid conflicts if two programs try to access the same resource or device simultaneously. To mediate such access, the kernel was given special rights on the system, leading to the division between user-space and kernel-space. A kernel connects the application software to the hardware of a computer. ... For library and office filing systems, see Library classification. ...


The microkernel concept was introduced in an effort to reverse the trend towards larger kernels and return to a system in which most tasks were completed by smaller utilities. In an era when a "normal" computer consisted of a hard disk for storage and a data terminal for input and output (I/O), the Unix file model worked quite well as most I/O was "linear". However, modern systems include networking and other new devices. As graphical user interfaces developed, the file model proved inadequate to the task of handling asynchronous events such as those generated by a mouse, and in the 1980s non-blocking I/O and the set of inter-process communication mechanisms was augmented (sockets, shared memory, message queues, semaphores), and functionalities such as network protocols were moved out of the kernel. Graphical overview of a microkernel A microkernel is a minimal computer operating system kernel providing only basic operating system services (system calls), while other services (commonly provided by kernels) are provided by user-space programs called servers. ... It has been suggested that dumb terminal be merged into this article or section. ... A contemporary computer mouse, with the most common standard features: two buttons and a scroll wheel. ... Asynchronous I/O, or non-blocking I/O, is a form of input/output processing that permits other processing to continue before the transmission has finished. ... Inter-Process Communication (IPC) is a set of techniques for the exchange of data between two or more threads in one or more processes. ... A Unix domain socket or IPC socket (inter-procedure call socket) is a virtual socket, similar to an internet socket that is used in POSIX operating systems for inter-process communication. ... // Diagram of a typical Shared memory system. ... In computer science, a message queue is a software-engineering component used for interprocess communication. ... This article is about the computer science application of mutual exclusion. ...


History

In the 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 Service), which was designed to run on the GE-645 mainframe computer. (Eventually this became a commercial product, although sales did not meet expectations.) Multics was an interactive operating system with many novel capabilities, including enhanced security. “MIT” redirects here. ... GE redirects here. ... Multics (Multiplexed Information and Computing Service) was an extraordinarily influential early time-sharing operating system. ... The GE-600 series was a family of 36-bit mainframe computers in the 1960s, built by General Electric (GE). ... For other uses, see Mainframe. ... For other uses, see Security (disambiguation). ...


AT&T Bell Labs pulled out of the Multics project 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 that computer called Space Travel.[1] However, he found that the game was too slow on the GE machine and was expensive, costing $75 per execution in scarce computing time.[2] Kenneth Lane Thompson (born February 4, 1943), commonly referred to as Ken Thompson (or simply Ken in hacker circles), is an American pioneer of computer science notable for his work with the B programming language and his shepherding the UNIX and Plan 9 from Bell Labs operating systems. ...


Thompson thus re-wrote the game in assembly language for Digital Equipment Corporation's PDP-7 with help from Dennis Ritchie. This experience, combined with his work on the Multics project, led Thompson to start a new operating system for the PDP-7. Thompson and Ritchie led a team of developers, including Rudd Canaday, at Bell Labs developing a file system as well as the new multi-tasking operating system itself. They included a command line interpreter and some small utility programs.[3] An assembly language is a low-level language for programming computers. ... Digital Equipment Corporation was a pioneering American company in the computer industry. ... A modified PDP-7 under restoration in Oslo, Norway The DEC PDP-7 is a minicomputer produced by Digital Equipment Corporation. ... Dennis Ritchie Dennis MacAlistair Ritchie (born September 9, 1941) is a computer scientist notable for his influence on ALTRAN, B, BCPL, C, Multics, and Unix. ...


1970s

In the 1970s the project was named Unics, and eventually could support two simultaneous users. Brian Kernighan invented this name as a contrast to Multics; the spelling was later changed to Unix. Brian Wilson Kernighan (IPA pronunciation: , the g is silent), (born 1942 in Toronto, Ontario, Canada) is a computer scientist who worked at Bell Labs alongside Unix creators Ken Thompson and Dennis Ritchie and contributed greatly to Unix and its school of thought. ...


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. This 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 PDP-11/20 assembly language. Bell Labs used this initial "text processing system", made up of Unix, roff, and the editor, for text processing of patent applications. Roff 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. The PDP-11 was a 16-bit minicomputer sold by Digital Equipment Corp. ... The title given to this article is incorrect due to technical limitations. ... Notepad is the standard text editor for Microsoft Windows A text editor is a piece of computer software for editing plain text. ... For other uses, see Patent (disambiguation). ... Troff is a document processing system developed by AT&T for the Unix operating system. ... This article or section is in need of attention from an expert on the subject. ... is the 307th day of the year (308th in leap years) in the Gregorian calendar. ... Year 1971 (MCMLXXI) was a common year starting on Friday (link will display full calendar) of the 1971 Gregorian calendar, known as the year of cyclohexanol. ...


In 1973, Unix was rewritten in the C programming language, contrary to the general notion at the time "that something as complex as an operating system, which must deal with time-critical events, had to be written exclusively in assembly language".[4] The migration from assembly language to the higher-level language C resulted in much more portable software, requiring only a relatively small amount of machine-dependent code to be replaced when porting Unix to other computing platforms. C is a general-purpose, block structured, procedural, imperative computer programming language developed in 1972 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system. ... An assembly language is a low-level language for programming computers. ... A high-level programming language is a programming language that, in comparison to low-level programming languages, may be more abstract, easier to use, or more portable across platforms. ... When applied to software the adjective quality may apply to source code as seen by software developers, or to applications software as seen by the end-users of the software. ... In computing, a platform describes some sort of framework, either in hardware or software, which allows software to run. ...


AT&T made Unix available to universities and commercial firms, as well as the United States government under licenses. The licenses included all source code including the machine-dependent parts of the kernel, which were written in PDP-11 assembly code. Copies of the annotated Unix kernel sources circulated widely in the late 1970s in the form of a much-copied book by John Lions of the University of New South Wales, the Lions' Commentary on UNIX 6th Edition, with Source Code, which led to considerable use of Unix as an educational example. The government of the United States, established by the United States Constitution, is a federal republic of 50 states, a few territories and some protectorates. ... John Lions (died December 5, 1998) was an Australian computer scientist. ... The University of New South Wales, also known as UNSW or colloquially as New South, is a university situated in Kensington, a suburb in Sydney, New South Wales, Australia. ... Lions Commentary on UNIX 6th Edition, with Source Code by John Lions (1976) contains the complete source code of the 6th Edition Unix kernel plus a commentary. ...


Versions of the Unix system were determined by editions of its user manuals, so that (for example) "Fifth Edition UNIX" and "UNIX Version 5" have both been used to designate the same thing. Development expanded, with Versions 4, 5, and 6 being released by 1975. These versions added the concept of pipes, leading to the development of a more modular code-base, increasing development speed still further. Version 5 and especially Version 6 led to a plethora of different Unix versions both inside and outside Bell Labs, including PWB/UNIX, IS/1 (the first commercial Unix), and the University of Wollongong's port to the Interdata 7/32 (the first non-PDP Unix). Sixth Edition Unix (also known as V6 Unix) was the first version of Unix to see wide release outside Bell Labs. ... PWB/UNIX (for Programmers Workbench) was an early version of the Unix operating system. ... INTERACTIVE Systems Corporation (ISC) was a computer software company, known for their versions of the Unix operating system. ... The University of Wollongong is a large University with approximately 21,000 students in the city of Wollongong, New South Wales, Australia. ... The Interdata 7/32 and 8/32 were 32-bit minicomputers developed by Interdata in the 1970s. ...


In 1978, UNIX/32V, for DEC's then new VAX system, was released. By this time, over 600 machines were running Unix in some form. Version 7 Unix, 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 released to a few universities, though they did generate papers describing the new work. This research led to the development of Plan 9 from Bell Labs, a new portable distributed system. UNIX/32V was an early version of the Unix operating system from Bell Laboratories, released late in 1978. ... Digital Equipment Corporation was a pioneering American company in the computer industry. ... VAX is a 32-bit computing architecture that supports an orthogonal instruction set (machine language) and virtual addressing (i. ... Seventh Edition Unix, also called Version 7 Unix, Version 7 or just V7, was an important early release of the Unix operating system. ... This article or section is not written in the formal tone expected of an encyclopedia article. ... Eight Edition Unix, also known as Version 8 Unix or V8, was a version of the Research Unix operating system developed and used internally at Bell Labs. ... Ninth Edition Unix, also known as Version 9 Unix or V9, was a version of the Research Unix operating system developed and used internally at the Bell Labs Information Sciences Research Division, released in September 1986. ... Tenth Edition Unix, also known as Version 10 Unix or V10, was the last version of the Research Unix operating system developed and used internally at Bell Labs. ... Plan 9 from Bell Labs is a distributed operating system, primarily used as a research vehicle. ...


1980s

A late-80s style Unix desktop running the X Window System graphical user interface. Shown are a number of client applications common to the MIT X Consortium's distribution, including Tom's Window Manager, an X Terminal, Xbiff, xload, and a graphical manual page browser.
A late-80s style Unix desktop running the X Window System graphical user interface. Shown are a number of client applications common to the MIT X Consortium's distribution, including Tom's Window Manager, an X Terminal, Xbiff, xload, and a graphical manual page browser.

AT&T licensed UNIX System III, based largely on Version 7, for commercial use, the first version launching in 1982. This also included support for the VAX. AT&T continued to issue licenses for older Unix versions. To end the confusion between all its differing internal versions, AT&T combined them into UNIX System V Release 1. This introduced a few features such as the vi editor and curses from the Berkeley Software Distribution of Unix developed at the University of California, Berkeley. This also included support for the Western Electric 3B series of machines. Image File history File links Download high-resolution version (900x750, 34 KB) This screenshot shows the X Window System running Toms Window Manager, and a number of client apps: the xlogo, an xterm, oclock, xbiff, xman, and xload. ... Image File history File links Download high-resolution version (900x750, 34 KB) This screenshot shows the X Window System running Toms Window Manager, and a number of client apps: the xlogo, an xterm, oclock, xbiff, xman, and xload. ... “X11” redirects here. ... twm desktop In computing, twm (Toms Window Manager or Tab Window Manager) is the standard window manager for the X Window System, version X11R4 onwards. ... xterm is the standard terminal emulator for the X Window System. ... xbiff is a small utility for the X Window System that shows a mailbox with its flag raised whenever the user has new e-mail. ... Almost all substantial UNIX and Unix-like operating systems have extensive documentation available as an electronic manual, split into multiple sections called man pages (short for manual pages and based on the command used to display them). ... System III was a version of the Unix operating system released by AT&Ts Unix System Group (USG). ... It has been suggested that Traditional Unix be merged into this article or section. ... vi editing a temporary, empty file. ... Curses is a terminal control library for Unix-like systems, enabling the construction of text user interface (TUI) applications. ... BSD redirects here. ... Sather Tower (the Campanile) looking out over the San Francisco Bay and Mount Tamalpais. ... Company Masthead Logo Logo until circa 1969, also current logo on company web site Logo 1969–1983 Hi Dan! Western Electric (sometimes abbreviated WE and WECo) was an American electrical engineering company, the manufacturing arm of AT&T from 1881 to 1995. ...


Since the newer commercial UNIX licensing terms were not as favorable for academic use as the older versions of Unix, the Berkeley researchers continued to develop BSD Unix as an alternative to UNIX System III and V, originally on the PDP-11 architecture (the 2.xBSD releases, ending with 2.11BSD) and later for the VAX-11 (the 4.x BSD releases). Many contributions to Unix first appeared on BSD releases, notably the C shell with job control (modelled on ITS). 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 several significant releases that contained network code: 4.1cBSD, 4.2BSD, 4.3BSD, 4.3BSD-Tahoe ("Tahoe" being the nickname of the Computer Consoles Inc. Power 6/32 architecture that was the first non-DEC release of the BSD kernel), Net/1, 4.3BSD-Reno (to match the "Tahoe" naming, and that the release was something of a gamble), Net/2, 4.4BSD, and 4.4BSD-lite. The network code found in these releases is the ancestor of much TCP/IP network code in use today, including code that was later released in AT&T System V UNIX and early versions of Microsoft Windows. The accompanying Berkeley Sockets API is a de facto standard for networking APIs and has been copied on many platforms. The C shell (csh) is a Unix shell developed by Bill Joy for the BSD Unix system. ... ITS, the Incompatible Timesharing System, was an early, revolutionary, and influential MIT time-sharing operating system; it was developed principally by the Artificial Intelligence Laboratory at MIT, with some help from Project MAC. ITS development was initiated in the late 1960s by those (notably the majority of the AI Lab... The Internet protocol suite is the set of communications protocols that implement the protocol stack on which the Internet runs. ... A computer network is an interconnection of a group of computers. ... A kernel connects the application software to the hardware of a computer. ... This article does not cite any references or sources. ... Windows redirects here. ... The Berkeley sockets application programming interface (API) comprises a library for developing applications in the C programming language that perform inter-process communication, most commonly across a computer network. ... API redirects here. ...


Other companies began to offer commercial versions 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; however, others were based on BSD instead. One of the leading developers of BSD, Bill Joy, went on to co-found Sun Microsystems in 1982 and created SunOS (now Solaris) for their workstation computers. In 1980, Microsoft announced its first Unix for 16-bit microcomputers called Xenix, which the Santa Cruz Operation (SCO) ported to the Intel 8086 processor in 1983, and eventually branched Xenix into SCO UNIX in 1989. Bill Joy William Nelson Joy (born Nov 8, 1954), commonly known as Bill Joy, is an American computer scientist. ... Sun Microsystems, Inc. ... SunOS was the version of the UNIX operating system developed by Sun Microsystems for their workstations and server systems until the early 1990s. ... Solaris is a computer operating system developed by Sun Microsystems. ... Sun SPARCstation 1+, 25 MHz RISC processor from early 1990s A workstation, such as a Unix workstation, RISC workstation or engineering workstation, is a high-end desktop or deskside microcomputer designed for technical applications. ... Microsoft Corporation, (NASDAQ: MSFT, HKSE: 4338) is a multinational computer technology corporation with global annual revenue of US$44. ... In computer science, 16-bit is an adjective used to describe integers that are at most two bytes wide, or to describe CPU architectures based on registers, address buses, or data buses of that size. ... Xenix was a version of the Unix operating system, licensed by Microsoft from AT&T in the late 1970s. ... Santa Cruz Operation (SCO) was a software company based in Santa Cruz, California that was best known for selling three Unix variants for Intel x86 processors: Xenix, SCO UNIX (later known as SCO OpenServer), and UnixWare. ... The 8086[1] is a 16-bit microprocessor chip designed by Intel in 1978, which gave rise to the x86 architecture. ... Tarantella, Inc. ...


For a few years during this period (before PC compatible computers with MS-DOS became dominant), industry observers expected that UNIX, with its portability and rich capabilities, was likely to become the industry standard operating system for microcomputers.[5] In 1984 several companies established the X/Open consortium with the goal of creating an open system specification based on UNIX. Despite early progress, the standardization effort collapsed into the "Unix wars," with various companies forming rival standardization groups. The most successful Unix-related standard turned out to be the IEEE's POSIX specification, designed as a compromise API readily implemented on both BSD and System V platforms, published in 1988 and soon mandated by the United States government for many of its own systems. One of the first PCs from IBM - the IBM PC model 5150. ... Microsofts disk operating system, MS-DOS, was Microsofts implementation of DOS, which was the first popular operating system for the IBM PC, and until recently, was widely used on the PC compatible platform. ... X/Open Company, Ltd. ... 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. ... The Institute of Electrical and Electronics Engineers or IEEE (pronounced as eye-triple-ee) is an international non-profit, professional organization incorporated in the State of New York, United States. ... POSIX or Portable Operating System Interface[1] 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 operating system. ... API redirects here. ... Year 1988 (MCMLXXXVIII) was a leap year starting on Friday (link displays 1988 Gregorian calendar). ... The government of the United States, established by the United States Constitution, is a federal republic of 50 states, a few territories and some protectorates. ...


AT&T added various features into UNIX System V, such as file locking, system administration, streams, new forms of IPC, the Remote File System and TLI. AT&T cooperated with Sun Microsystems and between 1987 and 1989 merged features from Xenix, BSD, SunOS, and System V into System V Release 4 (SVR4), independently of X/Open. This new release consolidated all the previous features into one package, and heralded the end of competing versions. It also increased licensing fees. File locking is a mechanism that enforces access to a computer file by only one user or process at any specific time. ... A system administrator is a person responsible for running, or running some aspect of, a computer system. ... The standard streams for input, output, and error The standard streams are preconnected input or output channels between a computer program and its environment (typically a text terminal) when it begins execution. ... IPC may refer to: Indian Penal Code Institute for printed circuits - an Association laying standards for every aspect of PCB design, manufacturing, and testing. ... The Remote File System (RFS) was a file access protocol developed by AT&T in the 1980s. ... In computer software, specifically networking, the Transport Layer Interface (TLI) was the networking API provided by AT&T UNIX System V Release 3. ... Xenix was a version of the Unix operating system, licensed by Microsoft from AT&T in the late 1970s. ... System V, previously known as AT&T System V, was one of the versions of the Unix computer operating system. ...


During this time a number of vendors including Digital Equipment, Sun, Addamax and others began building trusted versions of UNIX for high security applications, mostly designed for military and law enforcement applications. Addamax was founded in 1986 in Champaign, Illinois by Dr. Peter A. Alsberg. ... The phrase trusted operating system generally refers to an operating system that provides sufficient support for multilevel security and evidence of correctness to meet a particular set of government requirements. ...


1990s

In 1990, the Open Software Foundation released OSF/1, their standard Unix implementation, based on Mach and BSD. The Foundation was started in 1988 and was funded by several Unix-related companies that wished to counteract the collaboration of AT&T and Sun on SVR4. Subsequently, AT&T and another group of licensees formed the group "UNIX International" in order to counteract OSF. This escalation of conflict between competing vendors gave rise again to the phrase "Unix wars". The Open Software Foundation (OSF) was an organization founded in 1988 to create an open standard for an implementation of the Unix operating system. ... Mach is an operating system kernel developed at Carnegie Mellon University to support operating system research, primarily distributed and parallel computation. ... Unix International or UI was an association created in 1988 to promote open standards, especially the Unix operating system. ... 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. ...


In 1991, a group of BSD developers (Donn Seeley, Mike Karels, Bill Jolitz, and Trent Hein) left the University of California to found Berkeley Software Design, Inc (BSDI). BSDI produced 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, the free software ancestor of FreeBSD, OpenBSD, and NetBSD. Berkely Software Design Inc. ... 386BSD, also known as JOLIX, is a free BSD operating system for the Intel 80386. ... FreeBSD is a Unix-like free operating system descended from AT&T UNIX via the Berkeley Software Distribution (BSD) branch through the 386BSD and 4. ... OpenBSD is a Unix-like computer operating system descended from Berkeley Software Distribution (BSD), a Unix derivative developed at the University of California, Berkeley. ... NetBSD is a freely redistributable, open source version of the Unix-like BSD computer operating system. ...


By 1993 most commercial vendors had changed their variants of Unix to be based on System V with many BSD features added on top. The creation of the COSE initiative that year by the major players in Unix marked the end of the most notorious phase of the Unix wars, and was followed by the merger of UI and OSF in 1994. The new combined entity, which retained the OSF name, stopped work on OSF/1 that year. By that time the only vendor using it was Digital, which continued its own development, rebranding their product Digital UNIX in early 1995. AT&T UNIX System V was one of the versions of the UNIX operating system. ... The Common Open Software Environment or COSE was an initiative formed in March 1993 by the major Unix vendors of the time to create open, unified operating system (OS) standards. ... Digital Equipment Corporation was a pioneering American company in the computer industry. ... Tru64 is HPs (formerly Compaq; formerly DEC) 64-bit UNIX for the Alpha AXP platform. ...


Shortly after UNIX System V Release 4 was produced, AT&T sold all its rights to UNIX to Novell. (Dennis Ritchie likened this to the Biblical story of Esau selling his birthright for the proverbial "mess of pottage".[6]) Novell developed its own version, UnixWare, merging its NetWare with UNIX System V Release 4. Novell tried to use this to battle against Windows NT, but their core markets suffered considerably. For the road bicycle racing team previously known as Novell, see Rabobank (cycling). ... Esaw redirects here. ... The phrase mess of pottage means something of little value. ... UnixWare is a flavor of the Unix operating system. ... NetWare is a network operating system and the set of network protocols it uses to talk to client machines on the network. ... Windows NT (New Technology) is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. ...


In 1993, Novell decided to transfer the UNIX® trademark and certification rights to the X/Open Consortium.[7] In 1996, X/Open merged with OSF, creating the Open Group. Various standards by the Open Group now define what is and what is not a "UNIX" operating system, notably the post-1998 Single UNIX Specification. “(TM)” redirects here. ... X/Open Company, Ltd. ... The Open Software Foundation (OSF) was an organization founded in 1988 to create an open standard for an implementation of the Unix operating system. ... The Open Group is an industry consortium sponsored by IBM, Sun, HP, Hitachi, and Fujitsu for forming de facto-standards in the field of software engineering, in particular APIs. ... The Single UNIX Specification (SUS) is the collective name of a family of standards for computer operating systems to qualify for the name Unix. The SUS is developed and maintained by the Austin Group, based on earlier work by the IEEE and The Open Group. ...


In 1995, the business of administering and supporting the existing UNIX licenses, plus rights to further develop the System V code base, were sold by Novell to the Santa Cruz Operation.[8] Whether Novell also sold the copyrights is currently the subject of litigation (see below).


In 1997, Apple Computer sought out a new foundation for its Macintosh operating system and chose NEXTSTEP, an operating system developed by NeXT. The core operating system, which was based on BSD and the Mach kernel, was renamed Darwin after Apple acquired it. The deployment of Darwin in Mac OS X makes it, according to a statement made by an Apple employee at a USENIX conference, the most widely used Unix-based system in the desktop computer market. Apple Inc. ... NEXTSTEP is the original object-oriented, multitasking operating system that NeXT Computer, Inc. ... For other meanings, see Next. ... BSD redirects here; for other uses see BSD (disambiguation). ... Mach is an operating system kernel developed at Carnegie Mellon University to support operating system research, primarily distributed and parallel computation. ... Darwin is a free and open source, Unix-like operating system first released by Apple Inc. ... Mac OS X (pronounced ) is a line of graphical operating systems developed, marketed, and sold by Apple Inc. ... The USENIX Association is the Advanced Computing Technical Association. ... Bold text Desktop computer with several common peripherals (Monitor, keyboard, mouse, speakers, microphone and a printer) A desktop computer is a gay electronic machine computer which convert raw data into meaningful information, made for use on a desk in an office or home and is distinguished from portable computers such...


2000 to present

Unix has been losing market share, particularly to Linux. The Dot-com crash has led to significant consolidation of versions of Unix. Of the many commercial flavors of Unix that were born in the 1980s, only Solaris, HP-UX, and AIX are still doing relatively well in the market, though SGI's IRIX persisted for quite some time. Of these, Solaris has the largest market share.[9] The Dot-com bubble (or dot-com speculative bubble) refers to the approximately four years of time (1997–2001) in which stock markets in Western nations had their value increase rapidly and most significantly in the technology and new Internet sector. ... Solaris is a computer operating system developed by Sun Microsystems. ... HP-UX (Hewlett Packard UniX) is Hewlett-Packards proprietary implementation of the Unix operating system, based on System V (initially System III). ... 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. AIX has pioneered numerous network operating system enhancements, introducing new innovations later adopted by Unix-like operating systems... IRIX is a computer operating system developed by Silicon Graphics, Inc. ...

See also: SCO-Linux controversies
A modern Unix desktop environment (Solaris 10)

In 2000, SCO 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 legal action against various users and vendors of Linux. SCO had alleged that Linux contained copyrighted Unix code now owned by The SCO Group. Other allegations included trade-secret violations by IBM, or contract violations by former Santa Cruz customers who had since converted to Linux. However, Novell disputed 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, which also retained the core copyrights, veto rights over future licensing activities of SCO, and 95% of the licensing revenue. The SCO Group disagreed with this, and the dispute resulted in the SCO v. Novell lawsuit. On August 10, 2007, a major portion of the case (the fact that Novell had the copyright to UNIX, and that the SCO Group had improperly kept money that was due to Novell) was decided in Novell's favor. The court also ruled that "SCO is obligated to recognize Novell's waiver of SCO's claims against IBM and Sequent". After the ruling, Novell announced they have no interest in suing people over Unix and stated, "We don't believe there is Unix in Linux".[10][11][12] The SCO-Linux controversies are a series of legal and public disputes between the software company SCO Group (SCO) and various Linux vendors and users. ... Solaris 10 with the new Java Desktop System (JDS). ... Solaris 10 with the new Java Desktop System (JDS). ... The Solaris Operating System, usually known simply as Solaris, is a free Unix-based operating system introduced by Sun Microsystems in 1992 as the successor to SunOS. Solaris is known for its scalability, especially on SPARC systems, as well for being the origin for many innovative features such as DTrace... Santa Cruz Operation (SCO) was a software company based in Santa Cruz, California that was best known for selling three Unix variants for Intel x86 processors: Xenix, SCO UNIX (later known as SCO OpenServer), and UnixWare. ... The SCO Group, Inc. ... For other uses, see IBM (disambiguation) and Big Blue. ... SCO v. ... is the 222nd day of the year (223rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ...


In 2005, Sun Microsystems released the bulk of its Solaris system code (based on UNIX System V Release 4) into an open source project called OpenSolaris. New Sun OS technologies such as the ZFS file system are now first released as open source code via the OpenSolaris project; as of 2006 it has spawned several non-Sun distributions such as SchilliX, Belenix, Nexenta and MarTux. Sun Microsystems, Inc. ... It has been suggested that Traditional Unix be merged into this article or section. ... 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 Solaris Operating System technology. ... For other uses, see ZFS (disambiguation). ... 2006 is a common year starting on Sunday of the Gregorian calendar. ... SchilliX is a LiveCD operating system distribution based on OpenSolaris. ... BeleniX is an operating system distribution that is built using the OpenSolaris source base. ... In computing, Nexenta OS is an Debian-based GNU/Solaris operating system. ...


Standards

Beginning in the late 1980s, an open operating system standardization effort now known as POSIX provided a common baseline for all operating systems; IEEE based POSIX around the common structure of the major competing variants of the Unix system, publishing the first POSIX standard in 1988. In the early 1990s a separate but very similar effort was started by an industry consortium, the Common Open Software Environment (COSE) initiative, which eventually became the Single UNIX Specification administered by The Open Group). Starting in 1998 the Open Group and IEEE started the Austin Group, to provide a common definition of POSIX and the Single UNIX Specification. POSIX or Portable Operating System Interface[1] 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 operating system. ... The Institute of Electrical and Electronics Engineers or IEEE (pronounced as eye-triple-ee) is an international non-profit, professional organization incorporated in the State of New York, United States. ... The Common Open Software Environment or COSE was an initiative formed in March 1993 by the major Unix vendors of the time to create open, unified operating system (OS) standards. ... The Single UNIX Specification (SUS) is the collective name of a family of standards for computer operating systems to qualify for the name Unix. The SUS is developed and maintained by the Austin Group, based on earlier work by the IEEE and The Open Group. ... This article or section reads like an advertisement. ... The Austin Group or the Austin Common Standards Revision Group is a joint technical working group formed to develop and maintain a common revision of POSIX.1 and parts of the Single UNIX Specification. ...


In an effort towards compatibility, in 1999 several Unix system vendors agreed on SVR4's Executable and Linkable Format (ELF) as the standard for binary and object code files. The common format allows substantial binary compatibility among Unix systems operating on the same CPU architecture. In computing, the Executable and Linking Format (ELF, formerly called Extensible Linking Format) is a common standard file format for executables, object code, shared libraries, and core dumps. ...


The Filesystem Hierarchy Standard was created to provide a reference directory layout for Unix-like operating systems, particularly Linux. The Filesystem Hierarchy Standard (FHS) defines the main directories and their contents in Linux and other Unix-like computer operating systems. ...


Components

See also: list of Unix programs

The Unix system is composed of several components that are normally packaged together. By including — in addition to the kernel of an operating system — the development environment, libraries, documents, and the portable, modifiable source-code for all of these components, Unix was a self-contained software system. This was one of the key reasons it emerged as an important teaching and learning tool and has had such a broad influence. This is a list of Unix programs. ... A kernel connects the application software to the hardware of a computer. ...


The inclusion of these components did not make the system large — the original V7 UNIX distribution, consisting of copies of all of the compiled binaries plus all of the source code and documentation occupied less than 10MB, and arrived on a single 9-track magnetic tape. The printed documentation, typeset from the on-line sources, was contained in two volumes. Magnetic tape has been used for data storage for over 50 years. ...


The names and filesystem locations of the Unix components has changed substantially across the history of the system. Nonetheless, the V7 implementation is considered by many to have the canonical early structure:

  • Kernel — source code in /usr/sys, composed of several sub-components:
    • conf — configuration and machine-dependent parts, including boot code
    • dev — device drivers for control of hardware (and some pseudo-hardware)
    • sys — operating system "kernel", handling memory management, process scheduling, system calls, etc.
    • h — header files, defining key structures within the system and important system-specific invariables
  • Development Environment — Early versions of Unix contained a development environment sufficient to recreate the entire system from source code:
    • cc — C language compiler (first appeared in V3 Unix)
    • as — machine-language assembler for the machine
    • ld — linker, for combining object files
    • lib — object-code libraries (installed in /lib or /usr/lib) libc, the system library with C run-time support, was the primary library, but there have always been additional libraries for such things as mathematical functions (libm) or database access. V7 Unix introduced the first version of the modern "Standard I/O" library stdio as part of the system library. Later implementations increased the number of libraries significantly.
    • make - build manager (introduced in PWB/UNIX), for effectively automating the build process
    • include — header files for software development, defining standard interfaces and system invariants
    • Other languages — V7 Unix contained a Fortran-77 compiler, a programmable arbitrary-precision calculator (bc, dc), and the awk "scripting" language, and later versions and implementations contain many other language compilers and toolsets. Early BSD releases included Pascal tools, and many modern Unix systems also include the GNU Compiler Collection as well as or instead of a proprietary compiler system.
    • Other tools — including an object-code archive manager (ar), symbol-table lister (nm), compiler-development tools (e.g. lex & yacc), and debugging tools.
  • Commands — Unix makes little distinction between commands (user-level programs) for system operation and maintenance (e.g. cron), commands of general utility (e.g. grep), and more general-purpose applications such as the text formatting and typesetting package. Nonetheless, some major categories are:
    • sh — The "shell" programmable command-line interpreter, the primary user interface on Unix before window systems appeared, and even afterward (within a "command window").
    • Utilities — the core tool kit of the Unix command set, including cp, ls, grep, find and many others. Subcategories include:
      • System utilities — administrative tools such as mkfs, fsck, and many others
      • User utilities — environment management tools such as passwd, kill, and others.
    • Document formatting — Unix systems were used from the outset for document preparation and typesetting systems, and included many related programs such as nroff, troff, tbl, eqn, refer, and pic. Some modern Unix systems also include packages such as TeX and Ghostscript.
    • Graphics — The plot subsystem provided facilities for producing simple vector plots in a device-independent format, with device-specific interpreters to display such files. Modern Unix systems also generally include X11 as a standard windowing system and GUI, and many support OpenGL.
    • Communications — Early Unix systems contained no inter-system communication, but did include the inter-user communication programs mail and write. V7 introduced the early inter-system communication system UUCP, and systems beginning with BSD release 4.1c included TCP/IP utilities.
The 'man' command can display a 'man page' for every command on the system, including itself.
The 'man' command can display a 'man page' for every command on the system, including itself.
  • Documentation — Unix was the first operating system to include all of its documentation online in machine-readable form. The documentation included:
    • man — manual pages for each command, library component, system call, header file, etc.
    • doc — longer documents detailing major subsystems, such as the C language and troff

In computer programming, make is a utility for automatically building large applications. ... PWB/UNIX (for Programmers Workbench) was an early version of the Unix operating system. ... This article is about the programming language. ... Pascal is a structured imperative computer programming language, developed in 1970 by Niklaus Wirth as a language particularly suitable for structured programming. ... The GNU Compiler Collection (usually shortened to GCC) is a set of programming language compilers produced by the GNU Project. ... The title given to this article is incorrect due to technical limitations. ... Troff is a document processing system developed by AT&T for the Unix operating system. ... TBL is a three letter acronym which may be referring to: Tampa Bay Lightning, a National Hockey League sports team The Black Lotus, a demogroup The Big Lebowski, a 1998 Coen Brothers film. ... Part of the troff suite of Unix document layout tools, eqn is a preprocessor that formats equations for printing. ... refer is a program for managing bibliographic references, and citing them in troff documents. ... Pic is a domain-specific language by Brian Kernighan for specifying diagrams in terms of objects such as boxes with arrows between them. ... TeX (IPA: as in Greek, often in English; written with a lowercase e in imitation of the logo) is a typesetting system created by Donald Knuth. ... Ghostscript is a suite of software based on an interpreter for Adobe Systems PostScript and Portable Document Format (PDF) page description languages. ... In computing, the X Window System (commonly X11 or X) is a windowing system for bitmap displays. ... GUI can refer to the following: GUI is short for graphical user interface, a term used to describe a type of interface in computing. ... OpenGL (Open Graphics Library) is a standard specification defining a cross-language cross-platform API for writing applications that produce 2D and 3D computer graphics. ... UUCP stands for Unix to Unix CoPy. ... The Internet protocol suite is the set of communications protocols that implement the protocol stack on which the Internet runs. ... Image File history File links Man-man. ... Image File history File links Man-man. ...

Unix Impact

The Unix system had significant impact on other operating systems.


It was written in high level language as opposed to assembly language (which had been thought necessary for systems implementation on early computers). Although this followed the lead of Multics and Burroughs, it was Unix that popularized the idea. An assembly language is a low-level language for programming computers. ... Multics (Multiplexed Information and Computing Service) was an extraordinarily influential early time-sharing operating system. ... The Burroughs large systems were the largest of three series of Burroughs Corporation mainframe computers. ...


Unix had a drastically simplified file model compared to many contemporary operating systems, treating all kinds of files as simple byte arrays. The file system hierarchy contained machine services and devices (such as printers, terminals, or disk drives), providing a uniform interface, but at the expense of occasionally requiring additional mechanisms such as ioctl and mode flags to access features of the hardware that did not fit the simple "stream of bytes" model. The Plan 9 operating system pushed this model even further and eliminated the need for additional mechanisms. A computer printer, or more commonly a printer, produces a hard copy (permanent human-readable text and/or graphics) of documents stored in electronic form, usually on physical print media such as paper or transparencies. ... A computer terminal is an electronic or electromechanical hardware device that is used for entering data into, and displaying data from, a computer or a computing system. ... Disk Drive is the afternoon show on CBC Radio Two. ... In computing, the system call ioctl (IPA: ), found on Unix-like systems, allows an application to control or communicate with a device driver outside the usual read/write of data. ... Plan 9 from Bell Labs is a distributed operating system, primarily used as a research vehicle. ...

Linux has been adapted to boot from flash memory cards.
Linux has been adapted to boot from flash memory cards.

Unix also popularized the hierarchical file system with arbitrarily nested subdirectories, originally introduced by Multics. Other common operating systems of the era had ways to divide a storage device into multiple directories or sections, but they had a fixed number of levels, often only one level. Several major proprietary operating systems eventually added recursive subdirectory capabilities also patterned after Multics. DEC's RSX-11M's "group, user" hierarchy evolved into VMS directories, CP/M's volumes evolved into MS-DOS 2.0+ subdirectories, and HP's MPE group.account hierarchy and IBM's SSP and OS/400 library systems were folded into broader POSIX file systems. RSX-11 is a family of real-time operating systems mainly for PDP-11 computers created by Digital Equipment Corporation (DEC), common in the late 1970s and early 1980s. ... OpenVMS V7. ... CP/M is an operating system originally created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc. ... Microsofts disk operating system, MS-DOS, was Microsofts implementation of DOS, which was the first popular operating system for the IBM PC, and until recently, was widely used on the PC compatible platform. ... MPE (Multi-Programming Executive) is an early 1980s era business-oriented minicomputer operating system made by Hewlett-Packard. ... System Support Program (SSP) was an operating system for the IBM System/34 and System/36 minicomputers. ... OS/400 is an operating system used on IBMs line of AS/400 (now called iSeries) minicomputers. ...


Making the command interpreter an ordinary user-level program, with additional commands provided as separate programs, was another Multics innovation popularized by Unix. The Unix shell used the same language for interactive commands as for scripting (shell scripts — there was no separate job control language like IBM's JCL). Since the shell and OS commands were "just another program", the user could choose (or even write) his own shell. New commands could be added without changing the shell itself. Unix's innovative command-line syntax for creating chains of producer-consumer processes (pipelines) made a powerful programming paradigm (coroutines) widely available. Many later command-line interpreters have been inspired by the Unix shell. Screenshot of a sample Bash session, taken on Gentoo Linux. ... A shell script is a script written for the shell, or command line interpreter, of an operating system. ... Job Control Language (JCL) is a scripting language used on IBM mainframe operating systems to instruct the Job Entry Subsystem (that is, JES2 or JES3) on how to run a batch program or start a subsystem. ... In computer science, coroutines are program components that generalize subroutines to allow multiple entry points and suspending and resuming of execution at certain locations. ...


A fundamental simplifying assumption of Unix was its focus on ASCII text for nearly all file formats. There were no "binary" editors in the original version of Unix — the entire system was configured using textual shell command scripts. The common denominator in the I/O system was the byte — unlike "record-based" file systems. The focus on text for representing nearly everything made Unix pipes especially useful, and encouraged the development of simple, general tools that could be easily combined to perform more complicated ad hoc tasks. The focus on text and bytes made the system far more scalable and portable than other systems. Over time, text-based applications have also proven popular in application areas, such as printing languages (PostScript), and at the application layer of the Internet Protocols, e.g. Telnet, FTP, SSH, SMTP, HTTP and SIP. This article needs to be wikified. ... For the literary term, see Postscript. ... The Internet Protocol (IP) is a data-oriented protocol used for communicating data across a packet-switched internetwork. ...


Unix popularized a syntax for regular expressions that found widespread use. The Unix programming interface became the basis for a widely implemented operating system interface standard (POSIX, see above). A regular expression (abbreviated as regexp, regex or regxp) is a string that describes or matches a set of strings, according to certain syntax rules. ...


The C programming language soon spread beyond Unix, and is now ubiquitous in systems and applications programming. C is a general-purpose, block structured, procedural, imperative computer programming language developed in 1972 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system. ...


Early Unix developers were important in bringing the theory of modularity and reusability into software engineering practice, spawning a "Software Tools" movement. Modularity is a concept that has applications in the contexts of computer science, particularly programming, as well as cognitive science in investigating the structure of mind. ... In computer science and software engineering, reusability is the likelihood a segment of structured code can be used again to add new functionalities with slight or no modification. ... Software engineering is the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software. ...


Unix provided the TCP/IP networking protocol on relatively inexpensive computers, which contributed to the Internet explosion of world-wide real-time connectivity, and which formed the basis for implementations on many other platforms. (This also exposed numerous security holes in the networking implementations.)


The Unix policy of extensive on-line documentation and (for many years) ready access to all system source code raised programmer expectations, and contributed to the 1983 launch of the free software movement. The free software movement, also known as the free software philosophy, began in 1983 when Richard Stallman announced the GNU Project. ...


Over time, the leading developers of Unix (and programs that ran on it) evolved a set of cultural norms for developing software, norms which became as important and influential as the technology of Unix itself; this has been termed the Unix philosophy. The Unix philosophy is a set of cultural norms and philosophical approaches to developing software based on the experience of leading developers of the Unix operating system. ...


2038

Main article: Year 2038 problem

Unix stores system time values as the number of seconds from midnight January 1, 1970 (the "Unix Epoch") in variables of type time_t, historically defined as "signed 32-bit integer". On January 19, 2038, the current time will roll over from a zero followed by 31 ones (01111111111111111111111111111111) to a one followed by 31 zeros (10000000000000000000000000000000), which will reset time to the year 1901 or 1970, depending on implementation, because that toggles the sign bit. As many applications use OS library routines for date calculations, the impact of this could be felt much earlier than 2038; for instance, 30-year mortages may be calculated incorrectly beginning in the year 2008. Example showing how the date would reset (at 03:14:08 UTC on 19 January 2038). ... In computer science and computer programming, system time represents a computer systems notion of the passing of time. ... is the 1st day of the year in the Gregorian calendar. ... Year 1970 (MCMLXX) was a common year starting on Thursday (link shows full calendar) of the Gregorian calendar. ... Unix time, or POSIX time, is a system for describing points in time. ... Unix time, or POSIX time, is a system for describing points in time. ... is the 19th day of the year in the Gregorian calendar. ... 2038 (MMXXXVIII) will be a common year starting on Friday of the Gregorian calendar. ... In computer science the sign bit is the bit in a computer numbering format which indicates the sign of the number. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ...


Since times before 1970 are rarely represented in Unix time, one possible solution that is compatible with existing binary formats would be to redefine time_t as "unsigned 32-bit integer". However, such a kludge merely postpones the problem to February 7, 2106, and could introduce bugs in software that compares differences between two sets of time. Unix time passed 1,000,000,000 seconds in 2001-09-09T03:46:40. ... This article does not cite any references or sources. ... is the 38th day of the year in the Gregorian calendar. ... (Redirected from 2106) (21st century - 22nd century - 23rd century - other centuries) The twenty-second century comprises the years 2101 to 2200. ...


Some Unix versions have already addressed this. For example, in Solaris on 64-bit systems, time_t is 64 bits long, meaning that the OS itself and 64-bit applications will correctly handle dates for some 292 billion years. Existing 32-bit applications using a 32-bit time_t continue to work on 64-bit Solaris systems but are still prone to the 2038 problem.


Free Unix-like operating systems

Linux is a modern Unix-like system
Linux is a modern Unix-like system

In 1983, Richard Stallman announced the GNU project, an ambitious effort to create a free software Unix-like system; "free" in that everyone who received a copy would be free to use, study, modify, and redistribute it. The GNU project's own kernel development project, GNU Hurd, had not produced a working kernel, but the Linux kernel was released as free software in 1992 under the GNU General Public License. In addition to their use in the Linux operating system, many GNU packages — such as the GNU Compiler Collection (and the rest of the GNU toolchain), the GNU C library and the GNU core utilities — have gone on to play central roles in other free Unix systems as well. Richard Matthew Stallman (born March 16, 1953), often abbreviated rms,[1] is an American software freedom activist, hacker,[2] and software developer. ... GNU (pronounced ) is a computer operating system composed entirely of free software. ... Free software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with minimal restrictions only to ensure that further recipients can also do these things. ... Diagram of the relationships between several Unix-like systems A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification. ... Hurd redirects here. ... The Linux kernel is a Unix-like operating system kernel. ... GPL redirects here. ... This article is about operating systems that use the Linux kernel. ... The GNU Compiler Collection (usually shortened to GCC) is a set of programming language compilers produced by the GNU Project. ... The GNU toolchain is a blanket term given to the programming tools produced by the GNU project. ... Glibc is the GNU projects C standard library, licensed under the LGPL. The lead contributor and maintainer is Ulrich Drepper. ... Coreutils is a package of GNU software containing many of the basic tools such as cat, ls, and rm needed for Unix-like operating systems to function. ...


Linux distributions, comprising Linux and large collections of compatible software have become popular both with hobbyists and in business. Popular distributions include Red Hat Enterprise Linux, Fedora, SUSE Linux Enterprise, openSUSE, Debian GNU/Linux, Ubuntu, Mandriva Linux, Slackware Linux and Gentoo. Red Hat Enterprise Linux (often abbreviated to RHEL) is a Linux distribution produced by Red Hat and targeted toward the commercial market, including mainframes. ... Fedora (previously called Fedora Core) is an RPM-based, general purpose Linux distribution, developed by the community-supported Fedora Project and sponsored by Red Hat. ... SUSE (pronounced IPA: , properly (in German), ZOO-za, loosely SOO-sa [1] in English) is a major retail Linux distribution, produced in Germany and owned by Novell, Inc. ... SUSE (pronounced IPA: , properly (in German), ZOO-za, loosely SOO-sa [1] in English) is a major retail Linux distribution, produced in Germany and owned by Novell, Inc. ... Debian is a free operating system. ... Mandriva Linux (formerly Mandrakelinux or Mandrake Linux) is a Linux distribution created by Mandriva (formerly Mandrakesoft). ... Slackware is a Linux distribution. ... The Gentoo Linux operating system (pronounced ) is a Linux distribution named after the Gentoo penguin. ...


A free derivative of BSD Unix, 386BSD, was also released in 1992 and led to the NetBSD and FreeBSD projects. With the 1994 settlement of a lawsuit that UNIX Systems Laboratories brought against the University of California and Berkeley Software Design Inc. (USL v. BSDi), it was clarified that Berkeley had the right to distribute BSD Unix — for free, if it so desired. Since then, BSD Unix has been developed in several different directions, including OpenBSD and DragonFly BSD. BSD redirects here; for other uses see BSD (disambiguation). ... 386BSD, also known as JOLIX, is a free BSD operating system for the Intel 80386. ... NetBSD is a freely redistributable, open source version of the Unix-like BSD computer operating system. ... FreeBSD is a Unix-like free operating system descended from AT&T UNIX via the Berkeley Software Distribution (BSD) branch through the 386BSD and 4. ... UNIX Systems Laboratories or USL was originally organized as part of Bell Labs in 1989. ... This article is in need of attention. ... OpenBSD is a Unix-like computer operating system descended from Berkeley Software Distribution (BSD), a Unix derivative developed at the University of California, Berkeley. ... DragonFly BSD is a free Unix-like operating system created as a fork of FreeBSD 4. ...


Linux and BSD are now rapidly occupying much of the market traditionally occupied by proprietary Unix operating systems, as well as expanding into new markets such as the consumer desktop and mobile and embedded devices. Due to the modularity of the Unix design, sharing bits and pieces is relatively common; consequently, most or all Unix and Unix-like systems include at least some BSD code, and modern systems also usually include some GNU utilities in their distribution.


In 2005, Sun Microsystems released the bulk of the source code to the Solaris operating system, a System V variant, under the name OpenSolaris, making it the first actively developed commercial Unix system to be open sourced (several years earlier, Caldera had released many of the older Unix systems under an educational and later BSD license). As a result, a great deal of formerly proprietary AT&T/USL code is now freely available. Sun Microsystems, Inc. ... Solaris is a computer operating system developed by Sun Microsystems. ... OpenSolaris is an open source project created by Sun Microsystems to build a developer community around Solaris Operating System technology. ... 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. ... The BSD license is a permissive license and is one of the most widely used free software licenses. ...


Branding

See also: list of Unix systems

In October 1993, Novell, the company that owned the rights to the Unix System V source at the time, transferred the trademarks of Unix to the X/Open Company (now The Open Group),[13] and in 1995 sold the related business operations to Santa Cruz Operation.[14] Whether Novell also sold the copyrights to the actual software was the subject of a 2006 federal lawsuit, SCO v. Novell, which Novell won; the case is being appealed.[citation needed] Unix vendor SCO Group Inc. accused Novell of slander of title. Each version of the UNIX Time-Sharing System evolved from the version before, with version one evolving from the prototypal Unics. ... For the road bicycle racing team previously known as Novell, see Rabobank (cycling). ... “(TM)” redirects here. ... This article or section reads like an advertisement. ... Santa Cruz Operation (SCO) was a software company based in Santa Cruz, California that was best known for selling three Unix variants for Intel x86 processors: Xenix, SCO UNIX (later known as SCO OpenServer), and UnixWare. ... Not to be confused with copywriting. ... SCO v. ... The SCO Group, Inc. ... For the road bicycle racing team previously known as Novell, see Rabobank (cycling). ... In law, slander of title is normally a claim involving Real Estate in which one entity falsely claims to own another entitys property. ...


The present owner of the trademark UNIX® is The Open Group, an industry standards consortium. Only systems fully compliant with and certified to the Single UNIX Specification qualify as "UNIX®" (others are called "Unix system-like" or "Unix-like"). “(TM)” redirects here. ... This article or section reads like an advertisement. ... The Single UNIX Specification (SUS) is the collective name of a family of standards for computer operating systems to qualify for the name Unix. The SUS is developed and maintained by the Austin Group, based on earlier work by the IEEE and The Open Group. ... Diagram of the relationships between several Unix-like systems A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification. ...


By decree of The Open Group, the term "UNIX®" refers more to a class of operating systems than to a specific implementation of an operating system; those operating systems which meet The Open Group's Single UNIX Specification should be able to bear the UNIX® 98 or UNIX® 03 trademarks today, after the operating system's vendor pays a fee to The Open Group. Systems licensed to use the UNIX® trademark include AIX, HP-UX, IRIX, Solaris, Tru64 (formerly "Digital UNIX"), A/UX, Mac OS X 10.5 on Intel platforms,[15] and a part of z/OS. The Single UNIX Specification (SUS) is the collective name of a family of standards for computer operating systems to qualify for the name Unix. The SUS is developed and maintained by the Austin Group, based on earlier work by the IEEE and The Open Group. ... The Single UNIX Specification (SUS) is the collective name of a family of standards for computer operating systems to qualify for the name Unix. The SUS is developed and maintained by the Austin Group, based on earlier work by the IEEE and The Open Group. ... The Single UNIX Specification (SUS) is the collective name of a family of standards for computer operating systems to qualify for the name Unix. The SUS is developed and maintained by the Austin Group, based on earlier work by the IEEE and The Open Group. ... AIX (Advanced Interactive eXecutive) is the name given to a series of proprietary operating systems sold by IBM for several of its computer system platforms, based on UNIX System V. Before the product was ever marketed, the acronym AIX originally stood for Advanced IBM UNIX. The latest scalable AIX 5L... HP-UX (Hewlett Packard UniX) is Hewlett-Packards proprietary implementation of the Unix operating system, based on System V (initially System III). ... IRIX is a computer operating system developed by Silicon Graphics, Inc. ... The Solaris Operating System, usually known simply as Solaris, is a free Unix-based operating system introduced by Sun Microsystems in 1992 as the successor to SunOS. Solaris is known for its scalability, especially on SPARC systems, as well for being the origin for many innovative features such as DTrace... Tru64 is HPs (formerly Compaq; formerly DEC) 64-bit UNIX for the Alpha AXP platform. ... A/UX (from Apple Unix) is Apple Computers implementation of the Unix operating system for some of their Macintosh computers. ... Mac OS X (pronounced ) is a line of graphical operating systems developed, marketed, and sold by Apple Inc. ... Intel redirects here. ... z/OS Welcome Screen seen through a terminal emulator The title of this article begins with a capital letter due to technical limitations. ...


Sometimes a representation like "Un*x", "*NIX", or "*N?X" is used to indicate all operating systems similar to Unix. This comes from the use of the "*" and "?" characters as "wildcard" characters in many utilities. This notation is also used to describe other Unix-like systems, e.g. Linux, BSD, etc., that have not met the requirements for UNIX® branding from the Open Group.


The Open Group requests that "UNIX®" is always used as an adjective followed by a generic term such as "system" to help avoid the creation of a genericized trademark. A genericized trademark (also known as a generic trade mark or proprietary eponym) is a trademark or brand name that has become the colloquial or generic description for (or synonymous with) a particular class of product or service. ...


"Unix" was the original formatting, but the usage of "UNIX" remains widespread because, according to Dennis Ritchie, when presenting the original Unix paper to the third Operating Systems Symposium of the American Association for Computing Machinery, “we had a new typesetter and troff had just been invented and we were intoxicated by being able to produce small caps.”[16]. Many of the operating system's predecessors and contemporaries used all-uppercase lettering, so many people wrote the name in upper case due to force of habit. Dennis Ritchie Dennis MacAlistair Ritchie (born September 9, 1941) is a computer scientist notable for his influence on ALTRAN, B, BCPL, C, Multics, and Unix. ... The Association for Computing Machinery, or ACM, was founded in 1947 as the worlds first scientific and educational computing society. ...


Several plural forms of Unix are used to refer to multiple brands of Unix and Unix-like systems. Most common is the conventional "Unixes", but the hacker culture which created Unix has a penchant for playful use of language, and "Unices" (treating Unix as Latin noun of the third declension) is also popular. The Anglo-Saxon plural form "Unixen" is not common, although occasionally seen. Trademark names can be registered by different entities in different countries and trademark laws in some countries allow the same trademark name to be controlled by two different entities if each entity uses the trademark in easily distinguishable categories. The result is that Unix has been used as a brand name for various products including book shelves, ink pens, bottled glue, diapers, hair driers and food containers.[17] To meet Wikipedias quality standards, this article or section may require cleanup. ... For other uses, see Latins and Latin (disambiguation). ... Latin is an inflected language, and as such its nouns, pronouns, and adjectives must be declined in order to serve a grammatical function. ... Note: This page contains phonetic information presented in the International Phonetic Alphabet (IPA) using Unicode. ...


Common Unix commands

Wikibooks
Wikibooks Guide to Unix has a page on the topic of
See also: List of Unix utilities

Widely used Unix commands include: Image File history File links Wikibooks-logo-en. ... Wikibooks logo Wikibooks, previously called Wikimedia Free Textbook Project and Wikimedia-Textbooks, is a wiki for the creation of books. ... This is a list of UNIX utilities as specified by IEEE Std 1003. ...

  • Directory and file creation and navigation: ls cd pwd mkdir rm rmdir cp find touch mv
  • File viewing and editing: more less ed vi emacs head tail
  • Text processing: echo cat grep sort uniq sed awk cut tr split printf
  • File comparison: comm cmp diff patch
  • Miscellaneous shell tools: yes test xargs
  • System administration: chmod chown ps su w who
  • Communication: mail telnet ftp finger ssh
  • Authentication: su login passwd

References

  1. ^ Ritchie, Dennis M.. Space Travel: Exploring the solar system and the PDP-7. Retrieved on 2007-03-11.
  2. ^ The Creation of the UNIX* Operating System: The famous PDP-7 comes to the rescue
  3. ^ The Creation of the UNIX* Operating System: The UNIX system begins to take shape
  4. ^ Stallings, William. "Operating Systems: Internals and Design Principles" 5th ed, page 91. Pearson Education, Inc. 2005.
  5. ^ "UNIX". The Computer Chronicles. 1985.
  6. ^ http://groups.google.com/group/comp.unix.questions/browse_frm/thread/2f0b5e719fa3a3ec/3fa5e5fe4d58f96b
  7. ^ http://groups.google.com/group/comp.std.unix/msg/c9974cf0022884f8
  8. ^ HP, Novell and SCO To Deliver High-Volume UNIX OS With Advanced Network And Enterprise Services
  9. ^ Stephen Shankland (December 7, 2005). Itanium: A cautionary tale. Tech News. ZDNet. Retrieved on 2006-10-04. “In the third quarter of this year, 7,845 Itanium servers were sold, according to research by Gartner. That compares with 62,776 machines with Sun Microsystems' UltraSparc, 31,648 with IBM's Power, and 9,147 with HP's PA-RISC.”
  10. ^ Memorandum and Decision Order in SCO v. Novell
  11. ^ Memorandum and Decision Order Civil Case No. 2:04CV139DAK
  12. ^ Novell Won't Pursue Unix Copyrights August 15, 2007
  13. ^ http://groups.google.com/group/comp.std.unix/msg/c9974cf0022884f8
  14. ^ HP, Novell and SCO To Deliver High-Volume UNIX OS With Advanced Network And Enterprise Services
  15. ^ The Open Group. Mac OS X Version 10.5 Leopard on Intel-based Macintosh computers certification. Retrieved on 2007-06-12.
  16. ^ Unix
  17. ^ OtherUnix

Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 70th day of the year (71st in leap years) in the Gregorian calendar. ... Hosted by Stewart Cheifet (with co-host Gary Kildall in the 1980s), Computer Chronicles was the worlds most popular television program on personal technology during the height of the personal computer revolution. ... This article is about the year. ... is the 341st day of the year (342nd in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 277th day of the year (278th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 163rd day of the year (164th in leap years) in the Gregorian calendar. ... Peter H. Salus is a linguist, computer scientist, historian of technology, author and editor of books on computing. ... is the 152nd day of the year (153rd in leap years) in the Gregorian calendar. ... Year 1994 (MCMXCIV) The year 1994 was designated as the International Year of the Family and the International Year of the Sport and the Olympic Ideal by the United Nations. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 52nd day of the year in the Gregorian calendar. ... Also see: 2002 (number). ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... John Lions (died December 5, 1998) was an Australian computer scientist. ...

External links

Wikibooks
Wikibooks has a book on the topic of
Image File history File links Wikibooks-logo-en. ... Wikibooks logo Wikibooks, previously called Wikimedia Free Textbook Project and Wikimedia-Textbooks, is a wiki for the creation of books. ... The Open Directory Project (ODP), also known as dmoz (from , its original domain name), is a multilingual open content directory of World Wide Web links owned by Netscape that is constructed and maintained by a community of volunteer editors. ... Diagram of the relationships between several Unix-like systems A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification. ... An operating system (OS) is a software that manages computer resources and provides programmers with an interface used to access those resources. ... A/UX (from Apple Unix) is Apple Computers implementation of the Unix operating system for some of their Macintosh computers. ... AIX (Advanced Interactive eXecutive) is the name given to a series of proprietary operating systems sold by IBM for several of its computer system platforms, based on UNIX System V. Before the product was ever marketed, the acronym AIX originally stood for Advanced IBM UNIX. The latest scalable AIX 5L... BSD redirects here. ... BKUNIX is an operating system for Soviet Elektronika BK personal computer. ... For other uses, see DEMOS (disambiguation). ... DragonFly BSD is a free Unix-like operating system created as a fork of FreeBSD 4. ... FreeBSD is a Unix-like free operating system descended from AT&T UNIX via the Berkeley Software Distribution (BSD) branch through the 386BSD and 4. ... GNU (pronounced ) is a computer operating system composed entirely of free software. ... HP-UX (Hewlett Packard UniX) is Hewlett-Packards proprietary implementation of the Unix operating system, based on System V (initially System III). ... IRIX is a computer operating system developed by Silicon Graphics, Inc. ... This article is about operating systems that use the Linux kernel. ... The LynxOS RTOS is a Unix-like real-time operating system from LynuxWorks (formerly Lynx Real-Time Systems). Sometimes known as the Lynx Operating System, LynxOS features POSIX compliance and, more recently, Linux compatibility. ... Mac OS X (pronounced ) is a line of graphical operating systems developed, marketed, and sold by Apple Inc. ... MNOS (meaning MobilNaya Operatsionnaya Sistema (МобильНая Операционная Система, МНОС), or Portable Operating System) was a Unix-like operating system developed in the Soviet Union. ... NetBSD is a freely redistributable, open source version of the Unix-like BSD computer operating system. ... NEXTSTEP is the original object-oriented, multitasking operating system that NeXT Computer, Inc. ... OpenBSD is a Unix-like computer operating system descended from Berkeley Software Distribution (BSD), a Unix derivative developed at the University of California, Berkeley. ... Plan 9 from Bell Labs is a distributed operating system, primarily used as a research vehicle. ... 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. ... This article or section is not written in the formal tone expected of an encyclopedia article. ... 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. ... SINIX (later renamed to Reliant UNIX) was a version of the Unix operating system from Siemens Nixdorf Informationssysteme. ... The Solaris Operating System, usually known simply as Solaris, is a free Unix-based operating system introduced by Sun Microsystems in 1992 as the successor to SunOS. Solaris is known for its scalability, especially on SPARC systems, as well for being the origin for many innovative features such as DTrace... SUPER-UX, sometimes spelled SuperUx, is the UNIX-like operating system that is used on the Cray/NEC SX architecture supercomputers. ... AT&T UNIX System V was one of the versions of the UNIX operating system. ... Tru64 UNIX is HPs (formerly Compaq; formerly DEC) 64-bit Unix operating system for the DEC Alpha AXP platform. ... VxWorks is a Unix-like real-time operating system made and sold by Wind River Systems of Alameda, California, USA. Like most RTOSes, VxWorks includes a multitasking kernel with pre-emptive scheduling and fast interrupt response, extensive inter-process communications and synchronization facilities, and a file system. ... Xenix was a version of the Unix operating system, licensed by Microsoft from AT&T in the late 1970s. ... An operating system (OS) is a software that manages computer resources and provides programmers with an interface used to access those resources. ... A kernel connects the application software to the hardware of a computer. ... Graphical overview of a microkernel A microkernel is a minimal computer operating system kernel providing only basic operating system services (system calls), while other services (commonly provided by kernels) are provided by user-space programs called servers. ... It has been suggested that Monolithic system be merged into this article or section. ... Graphical overview of a hybrid kernel Hybrid kernel is a kernel architecture based on combining aspects of microkernel and monolithic kernel architectures used in computer operating systems. ... In computer engineering the kernel is the core of an operating system. ... In computing, loadable kernel modules, or LKM, are object files that contain code to extend the running kernel, or so-called base kernel, of an operating system. ... In computer science, a nanokernel or picokernel is a very minimalist operating system kernel. ... A device driver, or software driver is a computer program allowing higher-level computer programs to interact with a computer hardware device. ... An operating system usually segregates the available system memory into kernel space and user space. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... Process management is the ensemble of activities of planning and monitoring the performance of a process, especially in the sense of business process, often confused with reengineering. ... In computing, a process is an instance of a computer program that is being executed. ... In computing, multitasking is a method by which multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is... In computing, an interrupt is an asynchronous signal from hardware or software indicating the need for attention. ... Protected mode is an operational mode of x86-compatible CPUs of the 80286 series or later. ... In computer terms, supervisor mode is a hardware-mediated flag which can be changed by code running in system-level software. ... In computing, multitasking is a method by which multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is... For disk scheduling, see I/O scheduling. ... A context switch is the computing process of storing and restoring the state (context) of a CPU such that multiple processes can share a single CPU resource. ... In computing, cooperative multitasking (or non-preemptive multitasking) is a form of multitasking in which multiple tasks execute by voluntarily ceding control to other tasks at programmer-defined points within each task. ... Pre-emptive multitasking is a form of multitasking in which processes are not allowed to take an indefinitely long time to complete execution in the CPU. Each process, in turn, is granted a portion of CPU time (usually called a time slice, on the order of milliseconds). ... CPU modes (also called processor modes or privilege levels, and by other names) are operating modes for the central processing unit of some computers that place variable restrictions on the operations that can be performed by the CPU. Mode types At a minimum, any CPU with this type of architecture... Memory protection is a system that prevents one process from corrupting the memory of another process running on the same computer at the same time. ... Look up segmentation in Wiktionary, the free dictionary. ... This article is about computer virtual memory. ... This 68451 MMU could be used with the Motorola 68010 MMU, short for memory management unit or sometimes called paged memory management unit as PMMU, is a class of computer hardware components responsible for handling memory accesses requested by the CPU. Among the functions of such devices are the translation... It has been suggested that Access violation be merged into this article or section. ... A General Protection Fault (GPF) in the Intel x86 and AMD x86-64 architectures is a fault (a type of an interrupt) which can encompass several cases, where protection mechanisms within the processor architecture are violated by any of the programs that is running, whether it be the kernel or... AmigaOS is the default native operating system of the Amiga and AmigaOne personal computers. ... Filiation of Unix and Unix-like systems Unix (officially trademarked as UNIX®, sometimes also written as or ® with small caps) is a computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs including Ken Thompson, Dennis Ritchie and Douglas McIlroy. ... This article is about operating systems that use the Linux kernel. ... GNU (pronounced ) is a computer operating system composed entirely of free software. ... CP/M is an operating system originally created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc. ... MP/M was the multi-user version of the CP/M operating system, created by Digital Research. ... OS/2 is a computer operating system, initially created by Microsoft and IBM, then later developed by IBM exclusively. ... Microsofts disk operating system, MS-DOS, was Microsofts implementation of DOS, which was the first popular operating system for the IBM PC, and until recently, was widely used on the PC compatible platform. ... Windows redirects here. ... This article relates to both the original Classic Mac OS as well as Mac OS X, Apples more recent operating system. ... In computing, Bootstrapping refers to a process where a simple system activates another more complicated system that serves the same purpose. ... API redirects here. ... A virtual file system (VFS) or virtual filesystem switch is an abstraction layer on top of a more concrete file system. ... A computer network is an interconnection of a group of computers. ... GUI redirects here. ... The history of computer operating systems recapitulates to a degree, the recent history of computing. ... A hardware abstraction layer (HAL) is an abstraction layer, implemented in software, between the physical hardware of a computer and the software that runs on that computer. ...

  Results from FactBites:
 
OtherUnix (2624 words)
The Pannolini Unix diapers are not a mere will o' the wisp; one correspondent supplied an image of the box, and the current owner of this instance of the name responded to mail to their webmaster.
UNIX make moving not pain but almost pleasure, and are easily moved from room to room, upstairs or down....
Unix Electric Company of Korea, in business since 1979, has a diverse line of appliances for the body, the kitchen, and the home.
Unix - Wikipedia, the free encyclopedia (4786 words)
Unix or UNIX is a computer operating system originally developed in the 1960s and 1970s by a group of ATandT Bell Labs employees including Ken Thompson, Dennis Ritchie, and Douglas McIlroy.
The Unix systems are characterized by various concepts: plain text files, command line interpreter, hierarchical file system, treating devices and certain types of inter-process communication as files, etc. In software engineering, Unix is mainly noted for its use of the C programming language and for the Unix philosophy.
During the late 1970s and early 1980s, Unix's influence in academic circles led to massive adoption (particularly of the BSD variant, originating from the University of California, Berkeley) of Unix by commercial startups, the most notable of which is Sun Microsystems.
  More results at FactBites »

 
 

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