Linux:

Linux or GNU/Linux is an open source operating system for computers. The operating system of a computer is a collection of the basic instructions that tell the electronic parts of the computer what to do and how to work. "Open source" means that everyone can see how it works and change it if they want to. This is different from "closed source," which is software that makes it hard to change or see how it works. Windows is an example of a "closed source" operating system.

A lot of the important software made for computers is made for Windows because it is more popular. There is a lot of different software for Linux and since Linux is open source it means that most of the software for it is open source too, and free. This is one of the main reasons why some people like to use Linux more than Windows.

How Linux was made

In the 1980s, many people liked to use an operating system called Unix. But because they had to pay to use it, some people tried to write a new operating system that would work like Unix but would be open source.

A group of people called the GNU project wrote many different parts of a new operating system (GNU), but there was nothing that brought it all together. In 1991, Linus Torvalds began to work on a non-commercial replacement for MINIX as he was unhappy with it, while he was attending the University of Helsinki.^[2] This eventually became the Linux kernel.

Linus then shared the Linux kernel on Minix's user groups. Linus first named the OS "Freax" for "free" and "freak", using an X because it is popular in naming projects that are like Unix. Ari Lemmke, Torvald's coworker at the University who was responsible for the servers at the time, did not feel Freax was a good name. So, he called the project "Linux" without asking Torvalds. After a while later, Linus Torvalds finally agreed that Linux was the better name.

Linux relied on MINIX at first. With code from the GNU system freely available, it would be good for Linux if they could create an operating system together with the code combined. Code licensed under the GNU GPL can be used in other projects, as long as they also are released under the same or a similar license. In order to make the Linux kernel suitable for use with the code from the GNU Project, Linus Torvalds started a switch from his original license (which did not allow people to sell it) to the GNU GPL.^[3] Linux and GNU developers worked together to integrate GNU code with Linux to make a free operating system.

Because of the way that the new operating system was created by combining the work of the GNU project and Linus Torvalds, many people say that it's better to use the name GNU/Linux, but most people just say "Linux".

Since then, thousands of programmers and companies have worked to make Linux better.

In 1991, Torvalds began to work on a non-commercial replacement for MINIX while he was attending the University of Helsinki.^[4] This eventually became the Linux kernel.

Tux the penguin

The mascot of Linux is a cartoon penguin named "Tux". When a person sees the penguin on software and hardware, it means that it will work with Linux, and sometimes all systems that are like Unix.

The idea of the penguin came from the creator of Linux, Linus Torvalds. The image was made by a man named Larry Ewing in a competition to create a logo. The image, Tux, did not win, but it was picked as a mascot later.

Tux has now become a symbol for Linux, and sometimes even for open source. He can be seen in many different places and often, when people refer to Linux, they think about Tux. Tux has even been included in many video games, such as Super Tux (like Super Mario Bros.), Tux Racer (where players race Tux down an icy hill) and Pingus (like Lemmings).

Uses

Desktop

The performance of Linux on the desktop has been a topic discussed by many people, with at least one very important Linux kernel developer, Con Kolivas, saying that the Linux community prefers performance on servers rather than on desktops. He quit Linux development because he did not like this, and then gave a 'tell all' interview on the topic.^[13]

Servers and supercomputers

Linux has mainly been used as a server operating system, and has risen to be known by a lot of people in that area; Netcraft reported in February 2008 that five of the ten best internet hosting companies run Linux on their web servers.^[14] This is because of its stability and uptime, and the fact that desktop software with a graphical user interface for servers is often unneeded.

Linux is commonly used as an operating system for supercomputers. As of November 2007, out of the top 500 systems, 426 (85.2%) run Linux.^[15]

Pronunciation

Torvalds has made available an audio sample which indicates his own pronunciation, in English and Swedish.^[16]^[17]

Code size

A 2001 study of Red Hat Linux 7.1 found that this distribution contained 30 million lines of code. According to the study the distribution required about eight thousand man-years of development time. According to the study, if all this software had been developed by proprietary means, it would have cost about 1.08 billion dollars (year 2000 U.S. dollars) to develop in the United States.^[18]

Most of the code (71%) was written in the C programming language, but many other languages were used, including C++, assembly language, Perl, Python, Fortran, and various shell scripting languages. Slightly over half of all lines of code were licensed under the GPL. The Linux kernel was made up of 2.4 million lines of code, or 8% of the total.^[18]

Linux distributions and software

People who want to get Linux can download it from the Internet or buy it from a store or a website. Sometimes books and magazines about Linux have a CD with Linux on it. Any certain version of Linux is called a "distribution", or "distro". A Linux distribution includes the basic Linux operating system, along with some extra programs that help the user to do different jobs. Different distributions include different extra programs. The main distributions which are used by many people include:

People may have to pay a small amount for a distribution, to pay for the CD-ROM and to help the company to make their distribution better. In most cases where people have to pay, they are paying for the company to help the user after they install it, which is known as "support".

Licensing, trademark, and naming

The Linux kernel and most GNU software are licensed under the GNU General Public License (GPL). The GPL requires that anyone who distributes the Linux kernel must make the source code (and any modifications) available to the recipient under the same terms. In 1997, Linus Torvalds said, “Making Linux GPL'd was definitely the best thing I ever did.”^[19] Other key components of a Linux system may use other licenses; many libraries use the GNU Lesser General Public License (LGPL), a type of the GPL that is less restricted, and the X Window System uses the MIT License.

Linux

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