Linux Administration
This article is about the operating system.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 initially, was written entirely 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 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 portability to different computer platforms.
With AT&T being required to license the operating system’s source code to anyone who asked (due to an earlier antitrust case forbidding them from entering the computer business),Unix grew quickly and became widely adopted by academic institutions and businesses. In 1984, AT&T divested itself of Bell Labs. Free of the legal obligation requiring free licensing, Bell Labs began selling Unix as a proprietary product.
Linux is any Unix-like and POSIX-compliant computer operating system assembled under the model of free and open source software development and distribution. The main form of distribution are Linux distributions. The defining component of Linux is the Linux kernel, an operating system kernel first released on 5 October 1991, by Linus Torvalds. Because it considers Linux to be a variant of the GNU operating system, initiated in 1983 by Richard Stallman, the Free Software Foundation prefers the name GNU/Linux when referring to the operating system as a whole .
Linux was originally developed as a free operating system for Intel x86-based personal computers. It has since been ported to more computer hardware platforms than any other operating system. It is a leading operating system on servers and other big iron systems such as mainframe computers and supercomputers: as of June 2013, more than 95% of the world’s 500 fastest supercomputers run some variant of Linux,including all the 44 fastest. Linux also runs on embedded systems (devices where the operating system is typically built into the firmware and highly tailored to the system) such as mobile phones,tablet computers, network routers, building automation controls, televisions and video game consoles; the Android system in wide use on mobile devices is built on the Linux kernel.
The development of Linux is one of the most prominent examples of free and open source software collaboration: the underlying source code may be used, modified, and distributed — commercially or non-commercially — by anyone under licenses such as the GNU General Public License. Typically, Linux is packaged in a format known as a Linux distribution for desktop and server use. Some popular mainstream Linux distributions include Debian (and its derivatives such as Ubuntu and Linux Mint), Fedora (and its derivatives such as the commercial Red Hat Enterprise Linux and its open equivalent CentOS), Mandriva/Mageia, openSUSE (and its commercial derivative SUSE Linux Enterprise Server), and Arch Linux. Linux distributions include the Linux kernel, supporting utilities and libraries and usually a large amount of application software to fulfill the distribution’s intended use.
A distribution oriented toward desktop use will typically include the windowing systems X11 and Wayland and an accompanying desktop environment such as GNOME or the KDE Software Compilation. Some such 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 all graphical environments from the standard install and instead include other software to set up and operate a LAMP or a LYCE solution stack. Because Linux is freely redistributable, anyone may create a distribution for any intended use.
