A very popular open source operating system that runs on a variety of hardware platforms including x86, Itanium, PowerPC, ARM and IBM's entire product line. Based on many design principles used in the Unix operating system, and thereby often called a "Unix clone" or "Unix variant," Linux is widely deployed as a server OS and as an embedded OS. For example, Linux runs in most of the servers on the Internet and in countless appliances and consumer electronics devices (see embedded Linux). In the desktop market, Linux has nowhere near the same penetration; however, it gains ground slowly and steadily.

Linux is a multitasking, multiuser operating system that is known for its stability. Although modified by numerous people, its robustness stems from its Unix-like architecture that keeps peripheral software components isolated from the core software (the kernel).

Licensed under the GNU General Public License (GPL), Linux is the flagship product of the open source community (see open source and GNU General Public License). Numerous groups work on their own flavor of Linux, modifying it for various purposes, and several commercial organizations "distribute" Linux for a fee (see Linux distribution). Linux is an outstanding success because it embodies the major features of Unix in a modifiable open source package, including its compliance with the POSIX standard (see POSIX).

Not Just One User Interface
Linux employs the X Window rendering system for displaying data on screen. Because X Window provides only the basic window creation, it relies on third-party user interfaces to provide the window borders and buttons, menus, icons and desktop that users see and manipulate. KDE and GNOME are two of the most popular (see KDE and GNOME). A Linux distribution may include more than one user interface, all of which appear on screen somewhat similar to the Windows and Mac interfaces. See X Window.

From Minix to GNU/Linux
In 1990, Finnish computer science student Linus Torvalds created the Linux kernel (see kernel). He was inspired by Minix, a popular classroom teaching tool that was very close to Unix. Although Torvalds created the kernel, many of the supporting libraries, utilities and applications came from the GNU Project, which is why Linux is often designated as GNU/Linux. Over the years, a huge number of programmers have contributed to the GNU/Linux system. For more information, visit www.linux.com and www.gnu.com.

Torvalds maintains the official Linux kernel, which continually integrates patches and enhancements from the Linux community. For more information, visit www.kernel.org.

Linux Is Really "Lee-Nooks"
If you lived in Finland, you would say "lee-nooks" because Linus is pronounced "lee-noose." Since the English pronounce Linus as "line-iss," some call it "line-icks." More common is "lynn-icks," which splits the difference. No matter how you say it, Linux is very popular. See embedded Linux, KDE, GNOME, X Window, Lintel, Minix, Ubuntu, SuSE Linux, UnitedLinux, GNU, open source, Linux Foundation, Trinux, SCO and Red Hat.

See CompTIA.