Unix

Evolution of Unix and Unixshylike systems

Developer Ken Thompson DennisRitchie Brian KernighanDouglas McIlroy and JoeOssanna at Bell Labs

Written in C and Assembly language

OS family Unix

Working state Current

Source model Historically closedshysourcewhile some Unix projects(including BSD family andIllumos) are openshysource

Initial release Development started in1969First manual publishedinternally in

November 1971[1]

Announced outside Bell

Labs in October 1973[2]

Available in English

Kernel type Monolithic

Default user interface Commandshyline interfaceand Graphical (X WindowSystem)

License Varies some versions areproprietary others arefreeopenshysource software

UnixFrom Wikipedia the free encyclopedia

Unix (allshycaps UNIX for the trademark) is a family ofmultitasking multiuser computer operating systems thatderive from the original ATampT Unix developed in the1970s at the Bell Labs research center by KenThompson Dennis Ritchie and others[3]

Initially intended for use inside the Bell System ATampTlicensed Unix to outside parties from the late 1970sleading to a variety of both academic and commercialvariants of Unix from vendors such as the University ofCalifornia Berkeley (BSD) Microsoft (Xenix) IBM(AIX) and Sun Microsystems (Solaris) ATampT finallysold its rights in Unix to Novell in the early 1990s whichthen sold its Unix business to the Santa Cruz Operation(SCO) in 1995[4] but the UNIX trademark passed to theindustry standards consortium The Open Group whichallows the use of the mark for certified operating systemscompliant with the Single UNIX Specification (SUS)Among these is Apples OS X[5] which is the Unixversion with the largest installed base as of 2014

From the power users or programmers perspective Unixsystems are characterized by a modular design that issometimes called the Unix philosophy meaning thatthe operating system provides a set of simple tools thateach perform a limited wellshydefined function[6] with aunified filesystem as the main means ofcommunication[3] and a shell scripting and commandlanguage to combine the tools to perform complexworkflows Aside from the modular design Unix alsodistinguishes itself from its predecessors as the firstportable operating system almost the entire operatingsystem is written in the C programming language[7] thatallowed Unix to reach numerous platforms

Many clones of Unix have arisen over the years ofwhich Linux is the most popular having overtaken thepopularity of SUSshycertified Unices on server platformssince its inception in the early 1990s

Contents1 Overview

Official website unixorg(httpwwwunixorg)

Version 7 Unix the Research Unixancestor of all modern Unix systems

1 Overview2 History3 Standards4 Components5 Impact

51 Free Unix and Unixshylike variants52 ARPANET

6 Branding7 See also8 References9 Further reading10 External links

Overview

Originally Unix was meant to be a programmers workbench to beused for developing software to be run on multiple platforms[8][9]more than to be used to run application software The system grewlarger as the operating system started spreading in the academiccircle as users added their own tools to the system and shared themwith colleagues[10]

Unix was designed to be portable multishytasking and multishyuser in atimeshysharing configuration Unix systems are characterized byvarious concepts the use of plain text for storing data a hierarchicalfile system treating devices and certain types of intershyprocesscommunication (IPC) as files and the use of a large number ofsoftware tools small programs that can be strung together through a commandshyline interpreter using pipesas opposed to using a single monolithic program that includes all of the same functionality These conceptsare collectively known as the Unix philosophy Brian Kernighan and Rob Pike summarize this in TheUnix Programming Environment as the idea that the power of a system comes more from the relationshipsamong programs than from the programs themselves[11]

By the early 1980s users began seeing Unix as a potential universal operating system suitable forcomputers of all sizes[12][13] Unix operating systems are widely used in servers workstations and mobiledevices[14] The Unix environment and the clientndashserver program model were essential elements in thedevelopment of the Internet and the reshaping of computing as centered in networks rather than inindividual computers

Both Unix and the C programming language were developed by ATampT and distributed to government andacademic institutions which led to both being ported to a wider variety of machine families than any otheroperating system

Under Unix the operating system consists of many utilities along with the master control program thekernel The kernel provides services to start and stop programs handles the file system and other commonlowshylevel tasks that most programs share and schedules access to avoid conflicts when programs try to

Ken Thompson (sitting) and DennisRitchie working together at a PDPshy11

access the same resource or device simultaneously To mediate such access the kernel has special rightsreflected in the division between user space and kernel space

The microkernel concept was introduced in an effort to reverse the trend towards larger kernels and returnto a system in which most tasks were completed by smaller utilities In an era when a standard computerconsisted of a hard disk for storage and a data terminal for input and output (IO) the Unix file modelworked quite well as most IO was linear However modern systems include networking and other newdevices As graphical user interfaces developed the file model proved inadequate to the task of handlingasynchronous events such as those generated by a mouse In the 1980s nonshyblocking IO and the set ofintershyprocess communication mechanisms were augmented with Unix domain sockets shared memorymessage queues and semaphores In microkernel implementations functions such as network protocolscould be moved out of the kernel while conventional (monolithic) Unix implementations have networkprotocol stacks as part of the kernel

History

Main article History of Unix

The preshyhistory of Unix dates back to the midshy1960s when theMassachusetts Institute of Technology ATampT Bell Labs andGeneral Electric were developing an experimental timeshysharingoperating system called Multics for the GEshy645 mainframe[15]Multics introduced many innovations but had many problemsFrustrated by the size and complexity of Multics but not by theaims Bell Labs slowly pulled out of the project Their lastresearchers to leave Multics Ken Thompson Dennis Ritchie M DMcIlroy and J F Ossanna[16] decided to redo the work on a muchsmaller scale

The project gained the name UNICS (UNiplexed Information andComputing Service pronounced as eunuchs) in 1970 a pun onMultics (Multiplexed Information and Computer Services) the new operating system was an emasculatedMultics Peter H Salus credits Peter Neumann with the pun[17] By the end of 1971 this had become UNIX(written in allshycaps but not an acronym)

In 1972 Unix was rewritten in the C programming language[18] The migration from assembly to thehighershylevel language C resulted in much more portable software[19] requiring only a relatively smallamount of machineshydependent code to be replaced when porting Unix to other computing platforms BellLabs produced several versions of Unix that are collectively referred to as Research Unix In 1975 the firstsource license for UNIX was sold to faculty at the University of Illinois Department of Computer ScienceUIUC graduate student Greg Chesson (who had worked on the UNIX kernel at Bell Labs) was instrumentalin negotiating the terms of this license

During the late 1970s and early 1980s the influence of Unix in academic circles led to largeshyscale adoptionof Unix (BSD and System V) by commercial startups including Sequent HPshyUX Solaris AIX and XenixIn the late 1980s ATampT Unix System Laboratories and Sun Microsystems developed System V Release 4(SVR4) which was subsequently adopted by many commercial Unix vendors

The Common Desktop Environment(CDE) part of the COSE initiative

In the 1990s Unixshylike systems grew in popularity as Linux and BSD distributions were developed throughcollaboration by a worldwide network of programmers In 2000 Apple released Darwin that became thecore of the OS X operating system[20]

Standards

Beginning in the late 1980s an open operating systemstandardization effort now known as POSIX provided a commonbaseline for all operating systems IEEE based POSIX around thecommon structure of the major competing variants of the Unixsystem publishing the first POSIX standard in 1988 In the early1990s a separate but very similar effort was started by an industryconsortium the Common Open Software Environment (COSE)initiative which eventually became the Single UNIX Specification(SUS) administered by The Open Group Starting in 1998 the OpenGroup and IEEE started the Austin Group to provide a commondefinition of POSIX and the Single UNIX Specification which by2008 had become the Open Group Base Specification

In 1999 in an effort towards compatibility several Unix system vendors agreed on SVR4s Executable andLinkable Format (ELF) as the standard for binary and object code files The common format allowssubstantial binary compatibility among Unix systems operating on the same CPU architecture

The Filesystem Hierarchy Standard was created to provide a reference directory layout for Unixshylikeoperating systems and has mainly been used in Linux

Components

See also List of Unix programs

The Unix system is composed of several components that were originally packaged together By includingthe development environment libraries documents and the portable modifiable source code for all of thesecomponents in addition to the kernel of an operating system Unix was a selfshycontained software systemThis was one of the key reasons it emerged as an important teaching and learning tool and has had such abroad influence

The inclusion of these components did not make the system large ndash the original V7 UNIX distributionconsisting of copies of all of the compiled binaries plus all of the source code and documentation occupiedless than 10 MB and arrived on a single nineshytrack magnetic tape The printed documentation typeset fromthe onshyline sources was contained in two volumes

The names and filesystem locations of the Unix components have changed substantially across the historyof the system Nonetheless the V7 implementation is considered by many to have the canonical earlystructure

Kernel ndash source code in usrsys composed of several subshycomponentsconf ndash configuration and machineshydependent parts including boot codedev ndash device drivers for control of hardware (and some pseudoshyhardware)

sys ndash operating system kernel handling memory management process scheduling systemcalls etch ndash header files defining key structures within the system and important systemshyspecificinvariables

Development environment ndash early versions of Unix contained a development environment sufficientto recreate the entire system from source code

cc ndash C language compiler (first appeared in V3 Unix)as ndash machineshylanguage assembler for the machineld ndash linker for combining object fileslib ndash objectshycode libraries (installed in lib or usrlib) libc the system library with C runshytimesupport was the primary library but there have always been additional libraries for such thingsas mathematical functions (libm) or database access V7 Unix introduced the first version of themodern Standard IO library stdio as part of the system library Later implementationsincreased the number of libraries significantlymake ndash build manager (introduced in PWBUNIX) for effectively automating the build processinclude ndash header files for software development defining standard interfaces and systeminvariantsOther languages ndash V7 Unix contained a Fortranshy77 compiler a programmable arbitraryshyprecision calculator (bc dc) and the awk scripting language later versions andimplementations contain many other language compilers and toolsets Early BSD releasesincluded Pascal tools and many modern Unix systems also include the GNU CompilerCollection as well as or instead of a proprietary compiler systemOther tools ndash including an objectshycode archive manager (ar) symbolshytable lister (nm)compilershydevelopment tools (eg lex amp yacc) and debugging tools

Commands ndash Unix makes little distinction between commands (usershylevel programs) for systemoperation and maintenance (eg cron) commands of general utility (eg grep) and more generalshypurpose applications such as the text formatting and typesetting package Nonetheless some majorcategories are

sh ndash the shell programmable commandshyline interpreter the primary user interface on Unixbefore window systems appeared and even afterward (within a command window)Utilities ndash the core toolkit of the Unix command set including cp ls grep find and manyothers Subcategories include

System utilities ndash administrative tools such as mkfs fsck and many othersUser utilities ndash environment management tools such as passwd kill and others

Document formatting ndash Unix systems were used from the outset for document preparation andtypesetting systems and included many related programs such as nroff troff tbl eqn referand pic Some modern Unix systems also include packages such as TeX and GhostscriptGraphics ndash the plot subsystem provided facilities for producing simple vector plots in a deviceshyindependent format with deviceshyspecific interpreters to display such files Modern Unixsystems also generally include X11 as a standard windowing system and GUI and manysupport OpenGLCommunications ndash early Unix systems contained no intershysystem communication but didinclude the intershyuser communication programs mail and write V7 introduced the early intershysystem communication system UUCP and systems beginning with BSD release 41c includedTCPIP utilities

Documentation ndash Unix was the first operating system to include all of its documentation online inmachineshyreadable form The documentation included

man ndash manual pages for each command library component system call header file etcdoc ndash longer documents detailing major subsystems such as the C language and troff

Photo from USENIX 1984 includingDennis Ritchie (center)

Impact

See also Unixshylike

The Unix system had significant impact on other operating systemsIt won its success by the direct interaction by providing thesoftware at a nominal fee for educational use by running oninexpensive hardware and by being easy to adapt and move todifferent machines Unix was written in a highshylevel programminglanguage rather than assembly language (which had been thoughtnecessary for systems implementation on early computers)Although this followed the lead of Multics and Burroughs it wasUnix that popularized the idea

Unix had a drastically simplified file model compared to manycontemporary operating systems treating all kinds of files as simplebyte arrays The file system hierarchy contained machine services and devices (such as printers terminalsor disk drives) providing a uniform interface but at the expense of occasionally requiring additionalmechanisms such as ioctl and mode flags to access features of the hardware that did not fit the simplestream of bytes model The Plan 9 operating system pushed this model even further and eliminated theneed for additional mechanisms

Unix also popularized the hierarchical file system with arbitrarily nested subdirectories originallyintroduced by Multics Other common operating systems of the era had ways to divide a storage device intomultiple directories or sections but they had a fixed number of levels often only one level Several majorproprietary operating systems eventually added recursive subdirectory capabilities also patterned afterMultics DECs RSXshy11Ms group user hierarchy evolved into VMS directories CPMs volumesevolved into MSshyDOS 20+ subdirectories and HPs MPE groupaccount hierarchy and IBMs SSP andOS400 library systems were folded into broader POSIX file systems

Making the command interpreter an ordinary usershylevel program with additional commands provided asseparate programs was another Multics innovation popularized by Unix The Unix shell used the samelanguage for interactive commands as for scripting (shell scripts ndash there was no separate job controllanguage like IBMs JCL) Since the shell and OS commands were just another program the user couldchoose (or even write) his own shell New commands could be added without changing the shell itselfUnixs innovative commandshyline syntax for creating modular chains of producershyconsumer processes(pipelines) made a powerful programming paradigm (coroutines) widely available Many later commandshyline interpreters have been inspired by the Unix shell

A fundamental simplifying assumption of Unix was its focus on newlineshydelimited text for nearly all fileformats There were no binary editors in the original version of Unix ndash the entire system was configuredusing textual shell command scripts The common denominator in the IO system was the byte ndash unlikerecordshybased file systems The focus on text for representing nearly everything made Unix pipesespecially useful and encouraged the development of simple general tools that could be easily combined toperform more complicated ad hoc tasks The focus on text and bytes made the system far more scalable andportable than other systems Over time textshybased applications have also proven popular in applicationareas such as printing languages (PostScript ODF) and at the application layer of the Internet protocolseg FTP SMTP HTTP SOAP and SIP

Console screenshots of Debian(top a popular Linux distribution)and FreeBSD (bottom a popularUnixshylike operating system)

Unix popularized a syntax for regular expressions that found widespread use The Unix programminginterface became the basis for a widely implemented operating system interface standard (POSIX seeabove) The C programming language soon spread beyond Unix and is now ubiquitous in systems andapplications programming

Early Unix developers were important in bringing the concepts of modularity and reusability into softwareengineering practice spawning a software tools movement Over time the leading developers of Unix(and programs that ran on it) established a set of cultural norms for developing software norms whichbecame as important and influential as the technology of Unix itself this has been termed the Unixphilosophy

The TCPIP networking protocols were quickly implemented on the Unix versions widely used onrelatively inexpensive computers which contributed to the Internet explosion of worldwide realshytimeconnectivity and which formed the basis for implementations on many other platforms

The Unix policy of extensive onshyline documentation and (for many years) ready access to all system sourcecode raised programmer expectations and contributed to the 1983 launch of the free software movement

Free Unix and Unixshylike variants

See also Operating system sect UNIX and UNIXshylike operating systems

In 1983 Richard Stallman announced the GNU project an ambitiouseffort to create a free software Unixshylike system free in the sensethat everyone who received a copy would be free to use study modifyand redistribute it The GNU projects own kernel development projectGNU Hurd had not produced a working kernel but in 1991 LinusTorvalds released the Linux kernel as free software under the GNUGeneral Public License In addition to their use in the Linux operatingsystem many GNU packages ndash such as the GNU Compiler Collection(and the rest of the GNU toolchain) the GNU C library and the GNUcore utilities ndash have gone on to play central roles in other free Unixsystems as well

Linux distributions consisting of the Linux kernel and large collectionsof compatible software have become popular both with individualusers and in business Popular distributions include Red Hat EnterpriseLinux Fedora SUSE Linux Enterprise openSUSE DebianGNULinux Ubuntu Linux Mint Mandriva Linux Slackware Linuxand Gentoo

A free derivative of BSD Unix 386BSD was released in 1992 and led to the NetBSD and FreeBSDprojects With the 1994 settlement of a lawsuit brought against the University of California and BerkeleySoftware Design Inc (USL v BSDi) by UNIX Systems Laboratories it was clarified that Berkeley had theright to distribute BSD Unix for free if it so desired Since then BSD Unix has been developed in severaldifferent product branches including OpenBSD and DragonFly BSD

Linux and BSD are increasingly filling the market needs traditionally served by proprietary Unix operatingsystems as well as expanding into new markets such as the consumer desktop and mobile and embeddeddevices Because of the modular design of the Unix model sharing components is relatively commonconsequently most or all Unix and Unixshylike systems include at least some BSD code and some systemsalso include GNU utilities in their distributions

In a 1999 interview Dennis Ritchie voiced his opinion that Linux and BSD operating systems are acontinuation of the basis of the Unix design and are derivatives of Unix[21]

I think the Linux phenomenon is quite delightful because it draws so strongly on the basis thatUnix provided Linux seems to be the among the healthiest of the direct Unix derivativesthough there are also the various BSD systems as well as the more official offerings from theworkstation and mainframe manufacturers

In the same interview he states that he views both Unix and Linux as the continuation of ideas that werestarted by Ken and me and many others many years ago[21]

OpenSolaris was the openshysource counterpart to Solaris developed by Sun Microsystems which included aCDDLshylicensed kernel and a primarily GNU userland However Oracle discontinued the project upon theiracquisition of Sun which prompted a group of former Sun employees and members of the OpenSolariscommunity to fork OpenSolaris into the illumos kernel As of 2014 illumos remains the only active openshysource System V derivative

ARPANET

In May 1975 RFC 681 described the development of Network Unix by the Center for AdvancedComputation at the University of Illinois The system was said to present several interesting capabilities asan ARPANET minishyhost At the time Unix required a license from Bell Laboratories that at $20000(US)was very expensive for nonshyuniversity users while an educational license cost just $150 It was noted thatBell was open to suggestions for an ARPANETshywide license

Specific features found beneficial were the local processing facilities compilers editors a documentpreparation system efficient file system and access control mountable and unmountable volumes unifiedtreatment of peripherals as special files integration of the network control program (NCP) within the Unixfile system treatment of network connections as special files that can be accessed through standard UnixIO calls closing of all files on program exit and the decision to be desirable to minimize the amount ofcode added to the basic Unix kernel

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 timetransferred the trademarks of Unix to the XOpen Company (now The Open Group)[22] and in 1995 soldthe related business operations to Santa Cruz Operation (SCO)[23] Whether Novell also sold the copyrights

Promotional license plate by DigitalEquipment Corporation

HP9000 workstation running HPshyUXa certified Unix operating system

to the actual software was the subject of a 2006 federal lawsuit SCO v Novell which Novell won Thecase was appealed but on 30 Aug 2011 the United States Court of Appeals for the Tenth Circuit affirmedthe trial decisions closing the case[24] Unix vendor SCO Group Inc accused Novell of slander of title

The present owner of the trademark UNIX is The Open Group anindustry standards consortium Only systems fully compliant withand certified to the Single UNIX Specification qualify as UNIX(others are called Unix systemshylike or Unixshylike)

By decree of The Open Group the term UNIX refers more to aclass of operating systems than to a specific implementation of anoperating system those operating systems which meet The OpenGroups Single UNIX Specification should be able to bear the UNIX98 or UNIX 03 trademarks today after the operating systemsvendor pays a substantial certification fee and annual trademarkroyalties[25] to The Open Group Systems licensed to use the UNIXtrademark include AIX HPshyUX IRIX Solaris Tru64 (formerlyDigital UNIX) AUX OS X[26][27] and a part of zOS

Sometimes a representation like Unx NIX or NX is used toindicate all operating systems similar to Unix This comes from theuse of the asterisk () and the question mark characters as wildcardindicators in many utilities This notation is also used to describeother Unixshylike systems eg Linux BSD etc that have not metthe requirements for UNIX branding from the Open Group

The Open Group requests that UNIX is always used as an adjectivefollowed by a generic term such as system to help avoid the creation of a genericized trademark

Unix was the original formatting but the usage of UNIX remains widespread because it was once typeset insmall caps (UNIX) according to Dennis Ritchie when presenting the original Unix paper to the thirdOperating Systems Symposium of the American Association for Computing Machinery (ACM) we had anew typesetter and troff had just been invented and we were intoxicated by being able to produce smallcaps[28] Many of the operating systems predecessors and contemporaries used allshyuppercase lettering somany people wrote the name in upper case due to force of habit It is not an acronym[29]

Several plural forms of Unix are used casually to refer to multiple brands of Unix and Unixshylike systemsMost common is the conventional Unixes but Unices treating Unix as a Latin noun of the third declensionis also popular The pseudoshyAngloshySaxon plural form Unixen is not common although occasionally seenTrademark names can be registered by different entities in different countries and trademark laws in somecountries allow the same trademark name to be controlled by two different entities if each entity uses thetrademark in easily distinguishable categories The result is that Unix has been used as a brand name forvarious products including book shelves ink pens bottled glue diapers hair driers and food containers[30]

See also

Comparison of operating systems

Comparison of open source and closed sourceList of operating systemsList of Unix systemsList of Unix utilitiesMarket share of operating systemsOperating systems timelinePlan 9 from Bell LabsUnix timeYear 2038 problem

References1 McIlroy M D (1987) A Research Unix reader annotated excerpts from the Programmers Manual 1971ndash1986

(httpwwwcsdartmouthedu~dougreaderpdf) (PDF) (Technical report) CSTR Bell Labs 1392 Ritchie D M Thompson K (1974) The UNIX TimeshySharing System (httpcmbellshy

labscomcmcswhodmrcacmhtml) CACM 17 (7) 365ndash3753 Ritchie DM Thompson K (July 1978) The UNIX TimeshySharing System (httpsarchiveorgdetailsbstj57shy

6shy1905) Bell System Tech J (USA American Tel amp Tel) 57 (6) 1905ndash1929 doi101002j1538shy73051978tb02136x (httpsdxdoiorg1010022Fj1538shy73051978tb02136x) Retrieved December 9 2012

4 httpwwwnovellcomnewspressarchive199512pr95274html5 Apple Inc shy UNIX 03 (httpwwwopengrouporgopenbrandregisterbrand3602htm) Register of Certified

Products The Open Group6 Raymond Eric (2003shy09shy19) The Art of Unix Programming (httpwwwcatborg~esrwritingstaouphtml)

AddisonshyWesley ISBN 0shy13shy142901shy9 Retrieved 2009shy02shy097 Ritchie Dennis M (January 1993) The Development of the C Language (httpcmbellshy

labscomcmcswhodmrchisthtml) Retrieved 1 January 20088 The Elements of OperatingshySystem Style (httpwwwfaqsorgdocsartuch03s01html)9 TandyRadio Shack Book Whole Earth Software Catalog

(httpsarchiveorgstreamWhole_Earth_Software_Catalog_1984_PointWhole_Earth_Software_Catalog_1984_Point_djvutxt) 1984 UNIX was created by software developers for software developers to give themselves anenvironment they could completely manipulate

10 Powers Shelley Peek Jerry OReilly Tim Loukides Mike (2002) Unix Power Tools ISBN 0shy596shy00330shy711 Kernighan Brian W Pike Rob The UNIX Programming Environment 1984 viii12 Fiedler Ryan (October 1983) The Unix Tutorial Part 3 Unix in the Microcomputer Marketplace

(httpsarchiveorgstreambyteshymagazineshy1983shy101983_10_BYTE_08shy10_UNIXpagen133mode2up) BYTEp 132 Retrieved 30 January 2015

13 TandyRadio Shack Book Whole Earth Software Catalog(httpsarchiveorgstreamWhole_Earth_Software_Catalog_1984_PointWhole_Earth_Software_Catalog_1984_Point_djvutxt) 1984 The best thing about UNIX is its portability UNIX ports across a full range of hardwaremdashfrom the singleshyuser $5000 IBM PC to the $5 million Cray For the first time the point of stability becomes thesoftware environment not the hardware architecture UNIX transcends changes in hardware technology soprograms written for the UNIX environment can move into the next generation of hardware

14 Unixrsquos Revenge (httpwwwasymcocom20100929unixsshyrevenge) asymco 29 September 2010 Retrieved2010shy11shy09

15 Stuart Brian L (2009) Principles of operating systems design amp applications Boston MassachusettsThompson Learning p 23 ISBN 1shy4188shy3769shy5

16 Ritchie Dennis M The Evolution of the Unix Timeshysharing System (httpcmbellshylabscomcmcswhodmrhisthtml) Retrieved 2009shy11shy29

17 Salus Peter H (1994) A Quarter Century of UNIX Addison Wesley p 9 ISBN 0shy201shy54777shy518 Stallings William Operating Systems Internals and Design Principles 5th ed page 91 Pearson Education

Inc 2005

19 The History of Unix (httpsarchiveorgstreambyteshymagazineshy1983shy081983_08_BYTE_08shy08_The_C_Languagepagen189mode2up) BYTE August 1983 p 188 Retrieved 31 January 2015

20 Loading(httpdeveloperapplecomlibrarymacdocumentationMacOSXConceptualOSX_Technology_OverviewSystemTechnologySystemTechnologyhtmlapple_refdocuidTP40001067shyCH207shyBCICAIFJ)Developerapplecom Retrieved 2012shy08shy22

21 Benet Manuel (1999) Interview With Dennis M Ritchie(httpwwwlinuxfocusorgEnglishJuly1999article79html) LinuxFocusorg

22 Chuck Karish View profile More options The name UNIX is now the property of XOpen ndash compstdunix |Google Groups (httpgroupsgooglecomgroupcompstdunixmsgc9974cf0022884f8) GroupsgooglecomRetrieved 2010shy11shy09

23 HP Novell and SCO To Deliver HighshyVolume UNIX OS With Advanced Network And Enterprise Services(httpwwwnovellcomnewspressarchive199509pr95220html) Novellcom 20 September 1995 Retrieved2010shy11shy09

24 Jones Pamela SCO Files Docketing Statement and We Find Out What Its Appeal Will Be About(httpgroklawnetarticlephpstory=20100723230825165) Groklaw Groklawnet Retrieved 12 April 2011

25 The Open Group The Open Brand Fee Schedule (httpwwwopengrouporgopenbrandBrandfeeshtm)Retrieved 26 December 2011 The right to use the UNIX Trademark requires the Licensee to pay to The OpenGroup an additional annual fee calculated in accordance with the fee table set out below

26 The Open Group Mac OS X v105 Leopard on Intelshybased Macintosh computers certification(httpwwwopengrouporgopenbrandregisterbrand3555htm) Retrieved 2007shy06shy12

27 The Open Group Mac OS X v106 Snow Leopard certification(httpwwwopengrouporgopenbrandregisterbrand3581htm)

28 Unix (httpcatborgjargonhtmlUUnixhtml) Catborg Retrieved 2010shy11shy0929 Troy Douglas (1990) UNIX Systems Computing Fundamentals BenjaminCumming Publishing Company p 4

ISBN 0shy201shy19827shy430 Autres Unix autres moeurs (OtherUnix) (httpcmbellshylabscomcmcswhodmrotherunixhtml) Cmbellshy

labscom 1 April 2000 Retrieved 2010shy11shy09

Further reading

General

Ritchie DM Thompson K The UNIX TimeshySharing System (The Bell System Technical JournalJulyndashAugust 1978 Vol 57 No 6 Part 2(httpwebarchiveorgweb20101103053325httpbstjbellshylabscomoldfilesyear1978BSTJ19785706shy2html)) archived from the original on November 32010UNIX History (httpwwwlevenezcomunix) wwwlevenezcom Retrieved 17 March 2005AIX FreeBSD HPshyUX Linux Solaris Tru64 (httpwwwunixguidenet) UNIXguidenetRetrieved 17 March 2005Linux Weekly News February 21 2002 (httplwnnet20020221bigpagephp3) lwnnetRetrieved 7 April 2006Lions John Lions Commentary on the Sixth Edition UNIX Operating System(httpwwwlemiscomgrogDocumentationLions) with Source Code PeershytoshyPeerCommunications 1996 ISBN 1shy57398shy013shy7

Books

Salus Peter H A Quarter Century of UNIX Addison Wesley 1 June 1994 ISBN 0shy201shy54777shy5

Television

Look up Unix inWiktionary the freedictionary

Wikimedia Commons hasmedia related to Unix

The Wikibook Guide toUnix has a page on thetopic of Commands

Computer Chronicles (1985) UNIX (httpsarchiveorgdetailsUNIX1985)Computer Chronicles (1989) Unix (httpsarchiveorgdetailsunix_2)

External links

The UNIX System (httpwwwunixorg) at The OpenGroupThe Evolution of the Unix Timeshysharing System(httpswebarchiveorgweb20150408054606httpcmbellshylabscomcmcswhodmrhisthtml) at the Wayback Machine(archived April 8 2015)The Creation of the UNIX Operating System

(httpswebarchiveorgweb20140402192351httpwwwbellshylabscomhistoryunix) at theWayback Machine (archived April 2 2014)The Unix Tree files from historic releases (httpminnietuhsorgUnixTree)Unix (httpswwwdmozorgComputersSoftwareOperating_SystemsUnix) at DMOZThe Unix 1st Edition Manuals (httpmancatshyvorgunixshy1st)1982 film about Unix featuring Dennis Ritchie Ken Thompson Brian Kernighan Alfred Aho andmore (httptechchannelattcomplayshyvideocfm2012222ATampTshyArchivesshyTheshyUNIXshySystem)A History of UNIX before Berkeley UNIX Evolution 1975shy1984(httpwwwdarwinsyscomhistoryhisthtml)

Retrieved from httpsenwikipediaorgwindexphptitle=Unixampoldid=682531456

Categories Unix 1969 software Operating system families Timeshysharing operating systems

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