Linux is a free and open-source operating system based on the Linux kernel, which was created by Linus Torvalds in 1991. It is widely used on servers, desktops, and embedded devices. Major Linux distributions combine the Linux kernel with tools and libraries from the GNU operating system and various application software into a format that is easy to install and use. Linux has gained popularity for its security, reliability, and low cost as well as avoiding vendor lock-in.

2. is a Unix-like computer operating system one of the most prominent examples of free software and open source development: typically all underlying source code can be freely modified, used, and redistributed by anyone The name " Linux " comes from the Linux kernel, started in 1991 by Linus Torvalds

3. Predominantly known for its use in servers supported by corporations such as Dell , Hewlett-Packard , IBM , Novell , Oracle Corporation , Red Hat , and Sun Microsystems used as an operating system for a wide variety of computer hardware, including desktop computers, supercomputers, video game systems, such as the PlayStation 2 and PlayStation 3, several arcade games, and embedded devices such as mobile phones, routers, wristwatches, and stage lighting systems

4. Unix operating system was conceived and implemented in the 1960s and first released in 1970 Its wide availability and portability meant that it was widely adopted, copied and modified by academic institutions and businesses The GNU Project, started in 1984, had the goal of creating a " complete Unix-compatible software system " made entirely of free software

5. MINIX , a Unix-like system intended for academic use, was released by Andrew S. Tanenbaum in 1987 In 1991, Linus Torvalds began to work on a non-commercial replacement for MINIX while he was attending the University of Helsinki This eventually became the Linux kernel 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 distributions

6. Developed the linux kernel in 1991

7. Today Linux is used in numerous domains, from embedded systems to supercomputers, and has secured a place in server installations with the popular LAMP application stack LAMP ( L inux, A pache, M ySQL, P erl/ P HP/ P ython)

8. Linux is a modular Unix-like operating system uses a monolithic kernel, the Linux kernel, which handles process control, networking, and peripheral and file system access

9. Linux can be controlled by text-based command line interface (CLI) graphical user interface (GUI) (usually the default for desktop) through controls on the device itself (common on embedded machines) On desktop machines, KDE , GNOME and Xfce are the most popular user interfaces

10. The Linux market is growing rapidly, and the revenue of servers, desktops, and packaged software running Linux is expected to exceed $35.7 billion by 2008 IDC's report for Q1 2007 says that Linux now holds 12.7% of the overall server market

11. Proponents and analysts attribute the relative success of Linux to its: security reliability low cost and freedom from vendor lock-in

12. Frictional cost of switching operating systems Lack of support for certain hardware and application programs designed for Microsoft Windows recently Google has begun to fund Wine , which acts as a compatibility layer, allowing users to run some Windows programs directly under Linux

13. A 2001 study of Red Hat Linux 7.1 found that this distribution contained 30 million source lines of code. Using the Constructive Cost Model , the study estimated that this distribution required about eight thousand man-years of development time. If all this software had been developed by conventional proprietary means, it would have cost about 1.08 billion dollars (year 2000 U.S. dollars) to develop in the United States.

15. community developed operating system that is perfect for laptops, desktops and servers most popular of the many Linux distributions free of charge Everything you need on one CD Ubuntu's goals include providing an up-to-date yet stable operating system for the average user and having a strong focus on usability and ease of installation

16. sponsored by Canonical Ltd , owned by South African entrepreneur Mark Shuttleworth

17. The name of the distribution comes from the African concept of ubuntu which may be rendered roughly as " humanity toward others ", " we are people because of other people ", or " I am who I am because of who we all are “ is free software and can be shared by any number of users

18. releases new versions every six months, and supports those releases for 18 months with daily security fixes and patches to critical bugs LTS (Long Term Support) releases are supported for 3 years for desktops and 5 years for servers The most recent version, Ubuntu 8.04 ( Hardy Heron ) , was released on 24 April 2008 The next major version will be 8.10 ( Intrepid Ibex ) , scheduled for release in October 2008.

19. Productivity tools Browsing Photos Music and video Office applications Accessibility

20. Email Calendar Contacts. Tasks Instant messaging Pidgin IM is the extremely popular open source messaging tool

21. Rhythmbox Music and Totem video players Stream live radio Access (truly) free music stores Plug in your devices Share your music across a network Video

22. Photos with F-Spot manager Organise your photos (but in a fun way) Export to your favourite online photo gallery Edit Your Photos

23. Firefox 3 (Beta 5) Enhanced bookmarking, tagging and history Safer than ever Wonderful world of add-ons Improved address prompting in location bar No more pop-ups, forced add-ons and other irritations

24. Office tools with OpenOffice.org and more! Word processing Writer is for anything from writing a quick letter to producing an entire book.

25. Spreadsheet a tool to calculate, analyze, and present your data in numerical reports or charts.

26. Presentation Impress is an easy, and powerful tool for creating effective multimedia presentations.

27. Orca Assistive Technologies For sight impaired users Slow Keys and Gesture Support