Linux: Difference between revisions

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{{Main|Linux distribution}}

Many popular applications are available for a wide variety of operating systems. For example [[Mozilla Firefox]], [[OpenOffice.org]] flapping its wings and [[Blender (software)|Blender]] have downloadable versions for all major operating systems. Furthermore, some applications were initially developed for Linux, such as [[Pidgin (software)|Pidgin]], and [[GIMP]], and were ported to other operating systems including [[Microsoft Windows|Windows]] and [[Mac OS X]] due to their popularity. In addition, a growing number of proprietary desktop applications are also supported on Linux;<ref>{{cite web | url = http://www.iist.unu.edu/globaldesktop/ | title = The Global Desktop Project, Building Technology and Communities|accessdate = 2006-05-07 }}</ref> see [[List of proprietary software for Linux]]. In the field of animation and visual effects, most high end software, such as [[Maya (software)|AutoDesk Maya]], Softimage XSI and [[Shake (software)|Apple Shake]], is available for Linux, Windows and/or Mac OS X. There are also [[Linux gaming#Commercial games|several companies]] that have ported their own or other companies' games to Linux.

The primary difference between Linux and many other popular contemporary operating systems is that the [[Linux kernel]] and other components are [[free software|free]] and [[open source software]]. Linux is not the only such operating system, although it is by far the most widely used.<ref name="MarketShare09NOV">{{cite web|url = http://marketshare.hitslink.com/operating-system-market-share.aspx?qprid=8|title = Operating System Market Share|accessdate = 2009-12-11|last = Operating System Market Share |authorlink = |year = 2009|month = November}}</ref>

Some [[free software license|free]] and [[open source license|open source]] software licenses are based on the principle of [[copyleft]], a kind of reciprocity: any work derived from a [[copyleft]] piece of software must also be copyleft itself. The most common free software license, the [[GNU GPL]], is a form of [[copyleft]], and is used for the Linux kernel and many of the components from the [[GNU project]].

Linux based distributions are intended by developers for [[interoperability]] with other operating systems and established computing standards. Linux systems adhere to [[POSIX]],<ref>{{cite web | url = http://www.ukuug.org/newsletter/linux-newsletter/linux@uk21/posix.shtml | title = POSIX.1 (FIPS 151-2) Certification }}</ref> [[Single UNIX Specification|SUS]],<ref>{{cite web | title = How source code compatible is Debian with other Unix systems? | url = http://www.debian.org/doc/FAQ/ch-compat.en.html#s-otherunices | work = Debian FAQ | publisher = the Debian project }}</ref> [[International Organization for Standardization|ISO]], and [[American National Standards Institute|ANSI]] standards where possible, although to date only one Linux distribution has been POSIX.1 certified, Linux-FT.<ref>{{cite web | url = http://www.linuxjournal.com/article/0131 | title = Certifying Linux }}</ref>

Free software projects, although developed in a [[collaboration|collaborative]] fashion, are often produced independently of each other. The fact that the software licenses explicitly permit redistribution, however, provides a basis for larger scale projects that collect the software produced by stand-alone projects and make it available all at once in the form of a [[Linux distribution]].

A [[Linux distribution]], commonly called a "distro", is a project that manages a remote collection of system software and application software packages available for download and installation through a network connection. This allows the user to adapt the operating system to his/her specific needs. Distributions are maintained by individuals, loose-knit teams, volunteer organizations, and commercial entities. A distribution is responsible for the default configuration of the installed Linux kernel, general system security, and more generally integration of the different software packages into a coherent whole. Distributions typically use a [[package manager]] such as [[dpkg]], [[Synaptic (software)|Synaptic]], [[YAST]], or [[Portage (software)|Portage]] to install, remove and update all of a system's software from one central ___location.

===Community===

{{See also|Free software community|Linux User Group}}

A distribution is largely driven by its developer and user communities. Some vendors develop and fund their distributions on a volunteer basis, [[Debian]] being a well-known example. Others maintain a community version of their commercial distributions, as [[Red Hat]] does with [[Fedora (Linux distribution)|Fedora]] and [[Novell]] does with [[openSUSE]].

In many cities and regions, local associations known as [[Linux User Group]]s (LUGs) seek to promote their preferred distribution and by extension free software. They hold meetings and provide free demonstrations, training, technical support, and operating system installation to new users. Many [[Internet]] communities also provide support to Linux users and developers. Most distributions and free software / open source projects have [[IRC]] chatrooms or [[newsgroup]]s. [[Online forum]]s are another means for support, with notable examples being [[LinuxQuestions.org]] and the various distribution specific support and community forums, such as ones for [[Ubuntu (operating system)|Ubuntu]], [[Fedora (operating system)|Fedora]], and [[Gentoo Linux|Gentoo]]. Linux distributions host [[mailing list]]s; commonly there will be a specific topic such as usage or development for a given list.

There are several technology websites with a Linux focus. Print [[magazine]]s on Linux often include [[cover disk]]s including software or even complete Linux distributions.<ref>{{cite web | url=http://www.linuxformat.co.uk/dvd/ | title=Linux Format DVD contents | author=[[Linux Format]] | accessdate=2008-01-17 |archiveurl = http://web.archive.org/web/20070807222402/http://www.linuxformat.co.uk/dvd/ |archivedate = August 7, 2007}}</ref><ref>{{cite web | url=http://www.linux-magazine.com/resources/current_issue | title=Current Issue | author=linux-magazine.com | accessdate=2008-01-17 | authorlink=Linux Magazine }}</ref>

Although [[Linux distributions]] are generally available without charge, several large corporations sell, support, and contribute to the development of the components of the system and of [[free software]]. An analysis of the Linux kernel showed 75 percent of the code from December 2008 to January 2010 was developed by programmers working for corporations, leaving about 18 percent to the traditional, open source community.<ref>{{cite web | url=http://apcmag.com/linux-now-75-corporate.htm | title=75% of Linux code now written by paid developers

| author=|work=[[APC (magazine)|APC]] | accessdate=2010-01-22 }}</ref> Some of the major corporations that contribute include [[Dell]], [[IBM]], [[Hewlett-Packard|HP]], [[Oracle Corporation|Oracle]], [[Sun Microsystems]] (now part of Oracle), [[Novell]], and [[Nokia]]. A number of corporations, notably [[Red Hat]] and [[Novell]], have built a significant business around Linux distributions.

The [[free software licenses]], on which the various software packages of a distribution built on the Linux kernel are based, explicitly accommodate and encourage commercialization; the relationship between a Linux distribution as a whole and individual vendors may be seen as [[symbiosis|symbiotic]]. One common business model of commercial suppliers is charging for support, especially for business users. A number of companies also offer a specialized business version of their distribution, which adds proprietary support packages and tools to administer higher numbers of installations or to simplify administrative tasks.

Another business model is to give away the software in order to sell hardware. This used to be the norm in the computer industry, with operating systems such as [[CP/M]], [[Apple DOS]] and versions of [[Mac OS]] prior to 7.5 freely copyable (but not modifiable). As computer hardware standardized throughout the 1980s, it became more difficult for hardware manufacturers to profit from this tactic, as the OS would run on any manufacturers computer that shared the same architecture.

===Programming on Linux===

Linux distributions support dozens of [[programming language]]s. The most common collection of utilities for building both Linux applications and operating system programs is found within the [[GNU toolchain]], which includes the [[GNU Compiler Collection]] (GCC) and the [[GNU build system]].{{Citation needed|date=May 2011}} Amongst others, GCC provides compilers for [[Ada (programming language)|Ada]], [[C (programming language)|C]], [[C++]], [[Java (programming language)|Java]], and [[Fortran]]. [[Proprietary software|Proprietary]] compilers for Linux include the [[Intel C++ Compiler]], [[Sun Studio (software)|Sun Studio]], and IBM XL [[C (programming language)|C]]/[[C++]] Compiler. [[BASIC]] in the form of [[Visual Basic]] is supported in such forms as [[Gambas]], [[FreeBASIC]], and [[XBasic]].

Most distributions also include support for [[PHP]], [[Perl]], [[Ruby programming language|Ruby]], [[Python programming language|Python]] and other [[dynamic programming language|dynamic languages]]. While not as common, Linux also supports [[C Sharp (programming language)|C#]] (via [[Mono (software)|Mono]]), [[Vala (programming language)|Vala]], and [[Scheme programming language|Scheme]]. A number of [[Java Virtual Machine]]s and development kits run on Linux, including the original Sun Microsystems JVM ([[HotSpot]]), and IBM's J2SE RE, as well as many open-source projects like [[Kaffe]] and [[JikesRVM]].

The two main frameworks for developing graphical applications are those of [[GNOME]] and [[KDE]].{{Citation needed|date=May 2011}} These projects are based on the [[GTK+]] and [[Qt (toolkit)|Qt]] [[widget toolkit]]s, respectively, which can also be used independently of the larger framework. Both support a wide variety of languages. There are a number of [[Integrated development environment]]s available including [[Anjuta]], [[Code::Blocks]], [[CodeLite]], [[Eclipse (computing)|Eclipse]], [[Geany]], [[ActiveState Komodo]], [[KDevelop]], [[Lazarus (software)|Lazarus]], [[MonoDevelop]], [[NetBeans]], [[Qt Creator]] and [[Omnis Studio]], while the long-established editors [[Vim (text editor)|Vim]] and [[Emacs]] remain popular.<ref>{{cite web | first = Joe | last = Brockmeier | title = A survey of Linux Web development tools | url = http://programming.linux.com/programming/05/10/03/1828224.shtml?tid=63&tid=47 | accessdate = 2006-12-16 }}</ref>

==Uses==

As well as those designed for general purpose use on desktops and servers, distributions may be specialized for different purposes including: [[computer architecture]] support, [[Embedded Linux|embedded systems]], stability, security, localization to a specific region or language, targeting of specific user groups, support for [[real-time computing|real-time]] applications, or commitment to a given desktop environment. Furthermore, some distributions deliberately include only [[free software]]. Currently, over three hundred distributions are actively developed, with about a dozen distributions being most popular for general-purpose use.<ref>{{cite web | url = http://lwn.net/Distributions/ | title = The LWN.net Linux Distribution List | accessdate = 2006-05-19 }}</ref>

Linux is a widely [[porting|ported]] operating system kernel. The Linux kernel runs on a highly diverse range of [[computer architecture]]s: in the hand-held [[ARM architecture|ARM]]-based [[iPAQ]] and the [[mainframe computer|mainframe]] [[IBM]] [[IBM System z9|System z9]], [[IBM System z9|System z10]]; in devices ranging from [[mobile phone]]s to [[supercomputer]]s.<ref>{{cite web| url = http://www.freeos.com/articles/4737/ | title = If I could re-write Linux | first = Prakash | last = Advani | date = 8 February 2004 | accessdate = 2007-01-23 | publisher = freeos.com }}</ref> Specialized distributions exist for less mainstream architectures. The [[ELKS]] kernel [[fork (software development)|fork]] can run on [[Intel 8086]] or [[Intel 80286]] [[16-bit]] microprocessors, while the [[µClinux]] kernel fork may run on systems without a [[memory management unit]]. The kernel also runs on architectures that were only ever intended to use a manufacturer-created operating system, such as [[Macintosh]] computers (with both [[PowerPC]] and [[Intel]] processors), [[Personal digital assistant|PDAs]], [[video game console]]s, [[Digital audio player|portable music players]], and [[mobile phone]]s.

There are several industry associations and hardware [[Business conference|conferences]] devoted to maintaining and improving support for diverse hardware under Linux, such as [[FreedomHEC]].

===Desktop===

{{Main|Desktop Linux}}

The popularity of Linux on standard desktop computers and laptops has been increasing over the years.<ref>[http://www.linux.org/info/index.html What is Linux]</ref> Currently most distributions include a graphical user environment, with the two most popular environments being [[GNOME]] (which can utilize additional [[Shell (computing)|shells]] such as the default [[GNOME Shell]], the [[Ubuntu (operating system)|Ubuntu]] [[Unity (desktop environment)|Unity]]), and the [[KDE Plasma Desktop]].

The performance of Linux on the desktop has been a controversial topic; for example in 2007 [[Con Kolivas]] accused the Linux community of favoring performance on servers. He quit Linux kernel development because he was frustrated with this lack of focus on the desktop, and then gave a "tell all" interview on the topic.<ref>{{cite web|title=Linux: why I quit|url=http://apcmag.com/node/6735/|accessdate=2008-01-18|date=2007-07-24|work=APC Magazine|publisher=ACP Magazines}}</ref> Since then a significant amount of development has been undertaken in an effort to improve the desktop experience. Projects such as [[Upstart]] aim for a faster boot time.<ref>{{cite web|title=Performance of Java on Ubuntu vs Windows|url=http://www.phoronix.com/scan.php?page=article&item=java_vm_performance&num=1}}</ref>

Many popular applications are available for a wide variety of operating systems. For example [[Mozilla Firefox]], [[OpenOffice.org]] and [[Blender (software)|Blender]] have downloadable versions for all major operating systems. Furthermore, some applications were initially developed for Linux, such as [[Pidgin (software)|Pidgin]], and [[GIMP]], and were ported to other operating systems including [[Microsoft Windows|Windows]] and [[Mac OS X]] due to their popularity. In addition, a growing number of proprietary desktop applications are also supported on Linux;<ref>{{cite web | url = http://www.iist.unu.edu/globaldesktop/ | title = The Global Desktop Project, Building Technology and Communities|accessdate = 2006-05-07 }}</ref> see [[List of proprietary software for Linux]]. In the field of animation and visual effects, most high end software, such as [[Maya (software)|AutoDesk Maya]], Softimage XSI and [[Shake (software)|Apple Shake]], is available for Linux, Windows and/or Mac OS X. There are also [[Linux gaming#Commercial games|several companies]] that have ported their own or other companies' games to Linux.

Many types of applications available for Microsoft Windows and Mac OS X are also available for Linux. Commonly, either a [[free software]] application will exist which does the functions of an application found on another operating system, or that application will have a version that works on Linux, such as with [[Skype]] and some [[Linux gaming#Commercial games|video games]]. {{Citation needed|date=May 2011}} Furthermore, the [[Wine (software)|Wine]] project provides a Windows compatibility layer to run unmodified Windows applications on Linux. [[CrossOver]] is a proprietary solution based on the open source [[Wine (software)|Wine]] project that supports running Windows versions of [[Microsoft Office]], [[Intuit]] applications such as [[Quicken]] and [[QuickBooks]], [[Adobe Photoshop]] versions through CS2, and many popular games such as ''[[World of Warcraft]]'' and ''[[Team Fortress 2]]''. In other cases, where there is no Linux port of some software in areas such as [[desktop publishing]]<ref>{{cite web|url=http://www.freeos.com/articles/2540/ |title=Microsoft Office for Linux? |accessdate=2008-02-03 |last=Advani |first=Prakash |date=2000-10-27 |work=FreeOS |publisher=FreeOS Technologies (I) Pvt. Ltd. }}</ref> and [[professional audio]],<ref>{{cite web|url=http://arstechnica.com/guides/tweaks/linux-audio.ars |title=Editing audio in Linux |accessdate=2008-02-03 |last=Smith-Heisters |first=Ian |date=2005-10-11 |work=Ars Technica |publisher=Ars Technica, LLC }}</ref><ref>{{cite web|url=http://www.keyboardmag.com/article/linux-its-not/apr-07/27458 |title=Linux: It's Not Just For Computer Geeks Anymore |accessdate=2008-02-03 |last=Lumma |first=Carl |date = April 2007|work=Keyboard Magazine |publisher=New Bay Media, LLC. }}</ref><ref>{{cite web|url=http://www.soundonsound.com/sos/feb04/articles/mirrorimage.htm |title=Using Linux For Recording & Mastering |accessdate=2008-02-03 |last=James |first=Daniel |date = February 2004|work=Sound On Sound |publisher=SOS Publications Group }}</ref> there is equivalent software available on Linux.