By LinuxHPC.org and Cluster Resources
| Linux |
|
Linux (also known as GNU/Linux) is a Unix-like computer operating system. It is one of the most prominent examples of open source development and free software; unlike proprietary operating systems such as Windows or Mac OS, all of its underlying source code is available to the general public for anyone to use, modify, and redistribute freely.
Initially, Linux was primarily developed and used by individual enthusiasts on personal computers. Since then, Linux has gained the support of major corporations such as IBM, Sun Microsystems, Hewlett-Packard, and Novell for use in servers and is gaining popularity in the desktop market. It is used in systems ranging from supercomputers to mobile phones. Proponents and analysts attribute its success to its security, reliability, low cost, and freedom from vendor lock-in.
Applications
Linux has historically been used mainly as a server operating system, but its low cost, flexibility, and Unix background make it suitable for a wide range of applications. Linux is the cornerstone of the "LAMP" server-software combination (Linux, Apache, MySQL, Perl/PHP/Python) which has achieved popularity among developers, and which is one of the more common platforms for website hosting.
Due to its low cost and its high configurability, Linux is often used in embedded systems such as television set-top boxes, mobile phones, and handheld devices. Linux has become a major competitor to the proprietary Symbian OS found in many mobile phones, and it is an alternative to the dominant Windows CE and Palm OS operating systems on handheld devices. The popular TiVo digital video recorder uses a customized version of Linux. Several network firewall and router standalone products, including several from Linksys, use Linux internally, using its advanced firewalling and routing capabilities.
Linux is increasingly common as an operating system for supercomputers. In the November 2005 TOP500 list of supercomputers, the two fastest supercomputers in the world ran Linux. Of the 500 systems, 371 (74.2%) ran some version of Linux, including seven of the top ten.
Distributions
Linux is predominantly used as part of a Linux distribution (commonly called a "distro"). These are compiled by individuals, loose-knit teams, and commercial and volunteer organizations. They commonly include additional system and application software, an installer system to ease initial system setup, and integrated management of software installation and upgrading. Distributions are created for many different purposes, including computer architecture support, localization to a specific region or language, real-time applications, and embedded systems, and many 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.
A typical general-purpose distribution includes the Linux kernel, some GNU libraries and tools, command-line shells, the graphical X Window System and an accompanying desktop environment such as KDE or GNOME, together with thousands of application software packages, from office suites to compilers, text editors, and scientific tools.
Installation
The most common method of installing Linux on a personal computer is by booting from a CD-ROM that contains the installation program and installable software. Such a CD can be burned from a downloaded ISO image, shipped for free by request, purchased alone for a low price, or can be obtained as part of a box set that may also include manuals and additional commercial software.
As with servers, personal computers that come with Linux already installed are available from vendors including Hewlett-Packard and Dell, although generally only for their business desktop line.
Alternatives to traditional desktop installation include thin client installation, where the operating system is loaded and run from a centralised machine over a network connection; and running from a Live CD, where the computer boots the entire operating system from CD without first installing it on the computer's hard disk.
On embedded devices, Linux is typically held in the device's firmware and may or may not be consumer-accessible.
Programming on Linux
GCC is by far the most commonly used compiler family on Linux, providing frontends for C, C++ and Java among others. Most distributions also come installed with Perl, Python and other language interpreters, and several now include C# via the Mono project.
There are a number of Integrated development environments available including KDevelop, Anjuta, NetBeans, and Eclipse while the traditional editors Emacs and Vim are also provided and remain popular.
As well as these free and open source options, there are proprietary compilers and tools available from a range of companies such as Intel, PathScale and the Portland Group.
Support
Technical support is provided by commercial suppliers and by other Linux users, usually in online forums, IRC, newsgroups, and mailing lists. Linux User Groups have traditionally been organised to provide support for Linux in specific cities and regions.
The business model of commercial suppliers is generally dependent on charging for support, especially for business users. A number of companies 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.
All text used in this article is available under the GNU Free Documentation License. It uses material from the Wikipedia article "Linux".