Linux: Difference between revisions

Revision as of 11:43, 30 June 2011

Revision as of 11:44, 30 June 2011

Line 43:

A distribution oriented toward desktop use may include the [[X Window System]], the [[GNOME]] and [[KDE Plasma Workspaces|KDE Plasma]] [[desktop environment]]s. Other distributions may include a less resource intensive desktop such as [[LXDE]] or [[Xfce]] for use on older or less-powerful computers. A distribution intended to run as a server may omit any graphical environment from the standard install and instead include other software such as the [[Apache HTTP Server]] and a [[SSH server]] like [[OpenSSH]]. Because Linux is freely redistributable, it is possible for anyone to create a distribution for any intended use. Commonly used applications with desktop Linux systems include the [[Mozilla Firefox]] web browser, the [[OpenOffice.org]] or [[LibreOffice]] office application suites, and the [[GIMP]] image editor.

The name "Linux" comes from the Linux kernel, originally written in 1991 by [[Linus Torvalds]]. The main supporting [[user space]] system tools and libraries from the [[GNU Project]] (announced in 1983 by [[Richard Stallman]]) are the basis for the [[Free Software Foundation]]'s preferred name ''[[GNU/Linux naming controversy|GNU/Linux]]''.<ref name="lsag">{{cite book | url = http://www.tldp.org/LDP/sag/html/sag.html#GNU-OR-NOT | title = Linux System Administrator's Guide | chapter = 1.1 | edition = version 0.9 | year = 2004 | accessdate = 2007-01-18 | first = Alex | last = Weeks }}</ref><ref name="gnu_homepage">{{cite web|url=http://www.gnu.org/ |title=The GNU Operating System |publisher=Gnu.org |accessdate=2009-04-17}}</ref>

==History==

===Unix===

The [[Unix]] operating system was conceived and implemented in 1969 at [[AT&T]]'s Bell Laboratories in the [[United States]] by [[Ken Thompson]], [[Dennis Ritchie]], [[Douglas McIlroy]], and [[Joe Ossanna]]. It was first released in 1971 and was initially entirely written in [[assembly language]], a common practice at the time. Later, in a key pioneering approach in 1973, Unix was re-written in the programming language [[C (programming language)|C]] by [[Dennis Ritchie]] (with exceptions to the kernel and I/O). The availability of an operating system written in a high-level language allowed easier [[porting|portability]] to different computer platforms. With a legal glitch forcing AT&T to license the operating system's source code to anyone who asked,<ref name="faqs.org">{{cite web|url=http://www.faqs.org/docs/artu/ch02s01.html |title=Origins and History of Unix, 1969–1995 |publisher=Faqs.org |date= |accessdate=2010-11-09}}</ref> Unix quickly grew and became widely adopted by academic institutions and businesses. In 1984, AT&T divested itself of Bell Labs. Free of the legal glitch requiring free licensing, Bell Labs began selling Unix as a [[Proprietary software|proprietary]] product.

[[Image:Richard Matthew Stallman cropped.jpeg|upright|thumb|left|[[Richard Stallman]], founder of the [[GNU project]]]]

===GNU===

The [[GNU Project]], started in 1983 by [[Richard Stallman]], had the goal of creating a "complete Unix-compatible software system" composed entirely of [[free software]]. Work began in 1984.<ref name="gnu_announce">{{cite web|url=http://www.gnu.org/gnu/initial-announcement.html |title=About the GNU Project – Initial Announcement |publisher=Gnu.org |date=2008-06-23 |accessdate=2009-03-09}}</ref> Later, in 1985, Stallman started the [[Free Software Foundation]] and wrote the [[GNU General Public License]] (GNU GPL) in 1989. By the early 1990s, many of the programs required in an operating system (such as libraries, [[compiler]]s, [[text editor]]s, a [[Unix shell]], and a windowing system) were completed, although low-level elements such as [[device driver]]s, [[daemon (computer software)|daemons]], and the [[kernel (computer science)|kernel]] were stalled and incomplete.<ref name="gnu history">{{cite web|url=http://www.gnu.org/gnu/gnu-history.html |title=Overview of the GNU System |publisher=Gnu.org |date= |accessdate=2009-03-09}}</ref> Linus Torvalds has said that if the [[GNU kernel]] had been available at the time (1991), he would not have decided to write his own.<ref>{{cite web | url = http://www.dina.dk/~abraham/Linus_vs_Tanenbaum.html | title = Linus vs. Tanenbaum debate }}</ref>

===BSD===

Although not released until 1992 due to [[Berkeley Software Distribution#Net/2 and legal troubles|legal complications]], development of [[386BSD]], from which [[NetBSD]] and [[FreeBSD]] descended, predated that of Linux. [[Linus Torvalds]] has said that if 386BSD had been available at the time, he probably would not have created Linux.<ref name="meta">{{cite web|url=http://gondwanaland.com/meta/history/interview.html|title=The Choice of a GNU Generation – An Interview With Linus Torvalds|last=Linksvayer|first=Mike|year=1993|work=Meta magazine|accessdate=2009-01-20}}</ref>

===MINIX===

{{double image|right|AndrewTanenbaum2.png|130|Linus Torvalds cropped.jpeg|150|[[Andrew S. Tanenbaum]] (left), author of the [[MINIX]] operating system and [[Linus Torvalds]] (right), principal author of the [[Linux kernel]]}}

[[MINIX]] is an inexpensive minimal [[Unix-like]] operating system, designed for education in computer science, written by [[Andrew S. Tanenbaum]]. Starting with [[MINIX 3|version 3, MINIX]] was [[free software|free]] and redesigned for “serious” use.

In 1991 while attending the [[University of Helsinki]], Torvalds, curious about the operating systems <ref>{{cite newsgroup | title = What would you like to see most in minix? | newsgroup = comp.os.minix | id = [e-mail] | url = http://groups.google.com/group/comp.os.minix/msg/b813d52cbc5a044b | last = Torvalds | first = Linus | accessdate = 2006-09-09 }}</ref> and frustrated by the licensing of MINIX limiting it to educational use only (which prevented any commercial use), began to work on his own operating system which eventually became the [[Linux kernel]].

Torvalds began the development of the Linux kernel on MINIX, and applications written for MINIX were also used on Linux. Later Linux matured and it became possible for Linux to be developed under itself.<ref>{{cite news | title = Chicken and egg: How was the first linux gcc binary created?? | newsgroup = comp.os.minix | url = http://groups.google.com/group/comp.os.linux/msg/4ae6db18d3f49b0e }}</ref> Also GNU applications replaced all MINIX ones, because with code from the GNU system freely available, it was advantageous if this could be used with the fledgling operating system. Code licensed under the GNU GPL can be used in other projects, so long as they also are released under the same or a compatible license. In order to make the Linux available for commercial use, Torvalds initiated a switch from his original license (which prohibited commercial redistribution) to the GNU GPL.<ref>{{cite web | title = Release notes for Linux v0.12 | first = Linus | last = Torvalds | url = http://www.kernel.org/pub/linux/kernel/Historic/old-versions/RELNOTES-0.12 | authorlink = Linus Torvalds | date = 1992-01-05 | accessdate = 2007-07-23 | publisher = Linux Kernel Archives | quote = The Linux copyright will change: I've had a couple of requests to make it compatible with the GNU copyleft, removing the “you may not distribute it for money” condition. I agree. I propose that the copyright be changed so that it confirms to GNU ─ pending approval of the persons who have helped write code. I assume this is going to be no problem for anybody: If you have grievances ("I wrote that code assuming the copyright would stay the same") mail me. Otherwise The GNU copyleft takes effect since the first of February. If you do not know the gist of the GNU copyright ─ read it. }}</ref> Developers worked to integrate GNU components with Linux to make a fully functional and free operating system.<ref name="gnu history"/>

===Commercial and popular uptake===

[[File:Ubuntu 11.04 Installation SS.png|thumb|Ubuntu is a popular distribution of Linux]]

{{Main|Linux adoption}}

Today, Linux distributions are used in every ___domain, from [[embedded system]]s to [[supercomputer]]s,<ref>{{cite web | title = Linux system development on an embedded device | url = http://www-128.ibm.com/developerworks/library/l-embdev.html | first = Anand | last = Santhanam | coauthors = Vishal Kulkarni | work = DeveloperWorks | publisher = IBM | date = 1 March 2002 | accessdate = 2007-07-26 }}</ref><ref>{{cite news| last = Lyons | first = Daniel| title = Linux rules supercomputers | url = http://www.forbes.com/home/enterprisetech/2005/03/15/cz_dl_0315linux.html | accessdate = 2007-02-22 | work=Forbes}}</ref> and have secured a place in [[server (computing)|server]] installations often using the popular [[LAMP (software bundle)|LAMP]] application stack.<ref>{{cite web| last = Schrecker| first = Michael| title = Turn on Web Interactivity with LAMP | url = http://www.techsoup.org/learningcenter/webbuilding/page5067.cfm | accessdate = 2007-02-22}}</ref> Use of Linux distributions in home and enterprise desktops has been growing.<ref name="galli2007">{{cite news | first=Peter | last=Galli | coauthors= | title=Vista Aiding Linux Desktop, Strategist Says | date=2007-08-08 | publisher=Ziff Davis Enterprise Inc. | url =http://www.eweek.com/c/a/Linux-and-Open-Source/Vista-Aiding-Linux-Desktop-Strategist-Says/ | work =eWEEK | pages = | accessdate = 2007-11-19 | language = }}</ref><ref name="paul2007">{{cite news | first=Ryan | last=Paul | coauthors= | title=Linux market share set to surpass Win 98, OS X still ahead of Vista | date=2007-09-03 | publisher=Ars Technica, LLC | url =http://arstechnica.com/news.ars/post/20070903-linux-marketshare-set-to-surpass-windows-98.html | work =Ars Technica | pages = | accessdate = 2007-11-19 | language = }}</ref><ref name="beer2007">{{cite news | first=Stan | last=Beer | coauthors= | title=Vista to play second fiddle to XP until 2009: Gartner | date=2007-01-23 | publisher=iTWire | url =http://www.itwire.com.au/content/view/8842/53/ | work =iTWire | pages = | accessdate = 2007-11-19 | language = }}</ref><ref name="applications2007">{{cite web|url=http://marketshare.hitslink.com/report.aspx?qprid=2&qpmr=15&qpdt=1&qpct=3&qptimeframe=Y |title=Operating System Marketshare for Year 2007 |accessdate=2007-11-19 |date=2007-11-19 |work=Market Share |publisher=Net Applications }}</ref><ref name="xitimonitor2007">{{cite news | first= | last= | coauthors= | title=Vista slowly continues its growth; Linux more aggressive than Mac OS during the summer | date=2007-09-24 | publisher=AT Internet/XiTi.com | url =http://www.xitimonitor.com/en-us/internet-users-equipment/operating-systems-august-2007/index-1-2-7-107.html | work =XiTiMonitor | pages = | accessdate = 2007-11-19 | language = }}</ref><ref name="globalstats2007">{{cite web|url=http://www.w3counter.com/globalstats.php |title=Global Web Stats |accessdate=2007-11-19 |date=2007-11-10 |work=W3Counter |publisher=Awio Web Services LLC }}</ref><ref name="zeitgeist2004">{{cite web|url=http://www.google.com/press/zeitgeist/zeitgeist-jun04.html |title=June 2004 Zeitgeist |accessdate=2007-11-19 |date=2004-08-12 |work=Google Press Center |publisher=Google Inc. }}</ref> They have also gained popularity with various local and national governments. The federal government of Brazil is well known for its support for Linux.<ref>{{cite web | url = http://news.cnet.com/Brazils-love-of-Linux/2009-1042_3-6245409.html | title = Brazil's love of Linux | accessdate = 2009-02-21 }}</ref><ref>{{cite news | url = http://news.bbc.co.uk/2/hi/business/3445805.stm | title = Brazil falls in love with Linux | accessdate = 2009-02-21 | work=BBC News | date=2004-02-01 | first=Mark | last=Ashurst}}</ref> News of the Russian military creating their own Linux distribution has also surfaced, and has come to fruition as the G.H.ost Project.<ref>{{cite web | url = http://www.osor.eu/news/lv-minister-open-standards-improve-efficiency-and-transparency | title = LV: Minister: "Open standards improve efficiency and transparency" | accessdate = 2009-02-21 }}</ref> The Indian state of [[Kerala]] has gone to the extent of mandating that all state high schools run Linux on their computers.<ref>{{cite web | url = http://www.businessweek.com/globalbiz/content/sep2006/gb20060921_463452.htm | title = Linux Spreads its Wings in India | accessdate = 2009-02-21 }}</ref><ref>{{cite web | url = http://www.indianexpress.com/news/kerala-shuts-windows-schools-to-use-only-linux/280323/0 | title = Kerala shuts windows, schools to use only Linux | accessdate = 2009-06-22 }}</ref> [[People's Republic of China|China]] uses Linux exclusively as the operating system for its [[Loongson]] processor family to achieve technology independence.<ref>{{cite web | url = http://www.mdronline.com/watch/watch_Issue.asp?Volname=Issue+%23110308&on=1 | title = China’s Microprocessor Dilemma | accessdate = 2009-04-15 | publisher = [[Microprocessor Report]] }}</ref> In [[Spain]] some regions have developed their own Linux distributions, which are widely used in education and official institutions, like [[gnuLinEx]] in [[Extremadura]] and [[Guadalinex]] in [[Andalusia]]. [[Portugal]] is also using its own Linux distribution [[Caixa Mágica]], used in the Magalhães netbook<ref>{{cite web | url = http://www.caixamagica.pt/pag/f_notc00.php?id=213 | title = Magalhães equipped with Linux Caixa Mágica}}</ref> and the e-escola government program.<ref>{{cite web | url = http://www.caixamagica.pt/pag/f_notc00.php?id=204 | title = Oferta CM no programa e-Escolas surpreende o mercado}}</ref> [[France]] and [[Germany]] have also taken steps towards the adoption of Linux.<ref>{{cite web | url = http://seattlepi.com/business/48925_linuxop01.shtml | title = Some countries are choosing Linux systems over Microsoft | accessdate = 2009-02-21 }}</ref>

Linux distributions have also become popular in the [[netbook]] market, with many devices such as the [[Eee pc|ASUS Eee PC]] and [[Aspire One|Acer Aspire One]] shipping with customized Linux distributions installed.<ref>{{cite news | url = http://www.guardian.co.uk/technology/2009/may/28/netbooks-sales | title = Are netbooks losing their shine? | accessdate = 2010-06-02 | ___location=London | date=2009-05-28 | work=The Guardian | first=Jack | last=Schofield}}</ref>

===Current development===

Torvalds continues to direct the development of the kernel. Stallman heads the Free Software Foundation, which in turn supports the GNU components. Finally, individuals and corporations develop third-party non-GNU components. These third-party components comprise a vast body of work and may include both kernel modules and user applications and libraries. Linux vendors and communities combine and distribute the kernel, GNU components, and non-GNU components, with additional package management software in the form of [[Linux distribution]]s.

==Design==

A Linux-based system is a modular [[Unix-like]] operating system. It derives much of its basic design from principles established in Unix during the 1970s and 1980s. Such a system uses a [[monolithic kernel]], the [[Linux kernel]], which handles process control, networking, and [[peripheral]] and [[file system]] access. [[Device drivers]] are either integrated directly with the kernel or added as modules loaded while the system is running.

Separate projects that interface with the kernel provide much of the system's higher-level functionality. The GNU [[userland (computing)|userland]] is an important part of most Linux-based systems, providing the most common implementation of the [[C standard library|C library]], a popular [[shell (computing)|shell]], and many of the common [[Unix tool]]s which carry out many basic operating system tasks. The [[graphical user interface]] (or GUI) used by most Linux systems is built on top of an implementation of the [[X Window System]].

===User interface===

{{See also|User interface}}

Users operate a Linux-based system through a [[command line interface]] (CLI), a [[graphical user interface]] (GUI), or through controls attached to the associated hardware, which is common for embedded systems. For desktop systems, the default mode is usually a graphical user interface, by which the CLI is available through [[terminal emulator]] windows or on a separate [[virtual console (PC)|virtual console]]. Most low-level Linux components, including the GNU [[userland (computing)|userland]], use the CLI exclusively. The CLI is particularly suited for automation of repetitive or delayed tasks, and provides very simple [[inter-process communication]]. A graphical [[terminal emulator]] program is often used to access the CLI from a Linux desktop. A Linux system typically implements a CLI by a [[shell (computing)|shell]], which is also the traditional way of interacting with a Unix system. A Linux distribution specialized for servers may use the CLI as its only interface.

On desktop systems, the most popular user interfaces are the extensive [[desktop environment]]s [[KDE Plasma Desktop]], [[GNOME]], and [[Xfce]],<ref>{{cite web | title = Debian popularity-contest program information | url = http://times.debian.net/1092-30000-popcon-submissions }}</ref> though a variety of additional user interfaces exist. Most popular user interfaces are based on the [[X Window System]], often simply called "X". It provides [[network transparency]] and permits a graphical application running on one system to be displayed on another where a user may interact with the application.<ref name="manX">Manual page for "X" (xorg-docs 1:1.4-4 on Debian)</ref>