Linux facts for kids
Tux the penguin, the mascot of Linux
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| Company / developer | Community contributors, Linus Torvalds |
|---|---|
| Programmed in | C, assembly languages and others |
| OS family | Unix-like |
| Working state | Current |
| Source model | Open source |
| Initial release | September 17, 1991 |
| Marketing target | Cloud computing, embedded devices, mainframe computers, mobile devices, personal computers, servers, supercomputers |
| Available language(s) | Multilingual |
| Supported platforms | Alpha, ARC, ARM, C-Sky, Hexagon, LoongArch, m68k, Microblaze, MIPS, Nios II, OpenRISC, PA-RISC, PowerPC, RISC-V, s390, SuperH, SPARC, x86, Xtensa |
| Kernel type | Monolithic |
| Userland | GNU, BusyBox |
| Default user interface |
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| License | GPLv2 |
Linux (pronounced LIN-uuks) is a group of computer operating systems. These systems are based on the Linux kernel, which is the main part of the operating system. The Linux kernel was first released on September 17, 1991, by Linus Torvalds.
Linux is special because it is open-source. This means its code is available for anyone to see, use, and change. Linux is usually put together as a "distribution" (or "distro"). A distro includes the Linux kernel and other important software, like tools from the GNU Project. Many Linux distros use "Linux" in their name. However, some people, especially the Free Software Foundation, prefer "GNU/Linux" to show how important GNU software is.
Some popular Linux distros you might hear about are Debian, Fedora Linux, Arch Linux, and Ubuntu. Companies like Red Hat Enterprise Linux and SUSE Linux Enterprise also offer commercial versions. For desktop computers, Linux distros often come with a desktop environment like GNOME or KDE Plasma, which gives you a graphical way to use your computer. Servers might not have a graphical interface at all. Because Linux is free to share, anyone can create their own distro for any purpose.
Linux was first made for personal computers with Intel x86 processors. But now, it runs on more types of computer hardware than any other operating system. For example, Android phones use the Linux kernel, making Linux the most used operating system overall on mobile devices. Linux is also very popular on servers and is used on all of the world's fastest supercomputers.
Linux also works on embedded systems. These are devices where the operating system is built right into the device's memory and is made just for that device. This includes things like routers, smart home devices, video game consoles, televisions (like Samsung and LG Smart TVs), and even automobiles (Tesla, Audi, Mercedes-Benz). It's even used in spacecraft like the Falcon 9 rocket and the Perseverance rover!
Linux is a great example of how people can work together on open-source software. Anyone can use, change, and share its code, even for money, as long as they follow its licenses, like the GNU General Public License (GPL). The Linux kernel itself uses the GPLv2 license.
The Story of Linux
How it Started
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The Unix operating system was created in 1969 at AT&T's Bell Labs in the United States. It was first released in 1971. In 1973, a big step was taken when Unix was rewritten in the C programming language. This made it much easier to use Unix on different types of computers.
Because of old rules, AT&T had to share Unix's code with anyone who asked. This helped Unix become very popular in schools and businesses. But in 1984, AT&T changed its rules and started selling Unix as a private product. This meant users could no longer legally change the code.
This change led to the GNU Project, started in 1983 by Richard Stallman. His goal was to create a "complete Unix-like software system" that was entirely free software. By the early 1990s, many parts of this new system were ready, but the main part, called the kernel, was still unfinished.
Around the same time, a computer science professor named Andrew S. Tanenbaum created Minix in 1987. Minix was a small Unix-like operating system made for students to learn about operating systems. Its code was free to see, but its license limited its use.
Linus Torvalds' Idea
In 1990, Linus Torvalds was a student at the University of Helsinki. He took a Unix course and used a book that included the Minix operating system. This made him very interested in how operating systems work. In 1991, he became frustrated with Minix's rules, which only allowed it for educational use. So, he decided to start building his own operating system kernel. This kernel eventually became the Linux kernel.
Torvalds began developing Linux on Minix. As Linux grew, he started using GNU programs because they were free to use and change. He also changed his original license, which didn't allow commercial use, to the GNU GPL. This allowed other developers to combine GNU tools with the Linux kernel, creating a complete and free operating system.
How Linux Got Its Name
Linus Torvalds originally wanted to call his project "Freax." This name was a mix of "free," "freak," and "x" (like in Unix). He even used "Freax" in his project files for about six months. He thought "Linux" sounded too much like his own name and was a bit too proud.
In September 1991, to help with development, the files were uploaded to an internet server. Ari Lemmke, a coworker of Torvalds, was one of the people managing the server. He didn't like the name "Freax." So, without asking Torvalds, he named the project "Linux" on the server. Later, Torvalds agreed to the name.
Linus Torvalds said that "Linux" should be pronounced with a short 'i' sound, like in "print," and a 'u' sound, like in "put." He even included an audio file with the kernel code to show how to say it.
Linux Grows Up
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Linux started to become popular in the mid-1990s, especially in the world of supercomputers. Organizations like NASA began using clusters of cheaper computers running Linux instead of very expensive machines. Companies like Dell, IBM, and Hewlett-Packard also started offering support for Linux. This helped them compete with Microsoft in the operating system market.
Today, Linux is used everywhere. It's in small embedded systems and almost all supercomputers. It's also very common for servers. While it's still growing, more and more people are using Linux on their home and work computers.
Linux has had huge success in mobile devices. Android, which is based on the Linux kernel, is the most popular operating system for smartphones and tablets. Linux gaming is also becoming more popular, with companies like Valve supporting Linux and creating their own gaming-focused Linux distro called SteamOS. Many governments around the world, like in Brazil, China, and parts of Spain, also use Linux.
Who Works on Linux Now?
Linus Torvalds is still the main person guiding the development of the Linux kernel. Other people, like Greg Kroah-Hartman, help manage different parts of it. The Free Software Foundation supports the GNU components that are part of many Linux systems. Many other people and companies also create software for Linux.
Linux vendors and communities combine the kernel, GNU tools, and other software to create Linux distributions. These distros often include software to help you install, remove, and update programs easily.
How Linux Works
Many people who develop open-source software believe that the Linux kernel wasn't designed in a strict way. Instead, it "evolved" over time, like in nature. Linus Torvalds says that while Unix gave a basic idea, Linux grew with many changes. These changes were faster and more focused than random mutations.
Linux systems are like Unix systems, meaning they are built in a modular way. They use a single, main kernel (the Linux kernel) that handles important tasks. These tasks include managing programs, connecting to networks, and controlling hardware like printers and storage. Device drivers, which help the kernel talk to hardware, are either built into the kernel or added as modules when the system is running.
The GNU userland is a key part of most Linux systems. This includes the GNU C Library, which helps programs talk to the Linux kernel. It also includes the GNU toolchain, which are programming tools used to build Linux itself, and coreutils, which are basic Unix tools. Many Linux systems also use a graphical user interface (GUI) built on top of the X Window System or, more recently, Wayland.
Here are some parts you'd find in a Linux system:
- A bootloader: This program starts when you turn on your computer. It loads the Linux kernel into the computer's memory. Examples are GNU GRUB or LILO.
- An init program: This is the first program the Linux kernel starts. It then launches other important programs and services, like login screens. Examples are systemd or sysvinit.
- Software libraries: These are collections of code that other programs can use. The GNU C Library is a very common one.
- Basic Unix commands: These are simple tools for doing common tasks, like copying files or listing folders. The GNU coreutils are the standard set.
- Widget toolkits: These libraries help create the graphical parts of software applications, like buttons and menus. Popular ones include GTK and Qt.
- A package management system: This helps you easily install, remove, and update software on your system. Examples are dpkg or RPM.
- User interface programs: These are how you interact with the computer. They can be text-based (like a command-line shell) or graphical (like a desktop environment).
How You Use Linux
The way you interact with Linux is called the shell. It can be a text-based CLI or a GUI. For desktop computers, the GUI is usually the default, but you can always use the CLI through a special window.
CLI shells use text for both what you type and what the computer shows you. The most common CLI shell in Linux is called Bash. The CLI is great for automating tasks or doing things that don't need a visual display.
For desktop computers, the most popular user interfaces are GUIs, which come with full desktop environments. These include KDE Plasma, GNOME, MATE, and Xfce. Most of these GUIs are built on the X Window System, often just called "X." X allows graphical programs to run on one computer and be displayed on another.
Servers might only have a command-line interface for people who manage them. The actual users of the server might access it through a custom interface from another computer.
There are also different types of window managers for X11. These control how application windows look and where they are placed. Some are very simple, while others offer more features like built-in taskbars. Desktop environments usually include their own window managers.
Wayland is a newer system that aims to replace X11. It's becoming more widely used. Wayland combines the roles of the display server, window manager, and compositing manager into one.
How Linux is Developed
The biggest difference between Linux and many other operating systems is that the Linux kernel and its other parts are free and open-source software. This means anyone can use, change, and share the code. Many open-source licenses, like the GNU General Public License (GPL) used for the Linux kernel, follow a rule called copyleft. This means that any software built from a copyleft program must also be copyleft.
Linux systems are designed to work well with other operating systems and common computer standards. They try to follow standards like POSIX and LSB.
Even though free software projects are often developed by different groups, their licenses allow them to be shared. This makes it possible for bigger projects to collect software from many different places and offer it all together as a Linux distribution.
Many Linux distributions let you download and install software packages over the internet. This helps users customize their operating system for their specific needs. Distributions are maintained by individuals, volunteer groups, and companies. They are responsible for setting up the Linux kernel, keeping the system secure, and making sure all the different software packages work together. They usually use a "package manager" (like apt or yum) to install, remove, and update software.
The Linux Community
Linux distributions are largely driven by their communities of developers and users. Some companies develop and support their distros with volunteers, like Debian. Others, like Red Hat with Fedora, have a community version alongside their commercial products.
In many cities, there are Linux User Groups (LUGs). These groups promote their favorite Linux distros and free software. They hold meetings, offer free demonstrations, training, and technical support. Many online communities also help Linux users and developers. Most distros and open-source projects have chatrooms or online forums where you can get help.
There are also many websites and magazines focused on Linux.
Even though Linux distros are usually free, many large companies sell services, support, and contribute to the development of Linux. A study in 2017 showed that most of the Linux kernel code was written by programmers who were paid for their work. Companies like Intel, Samsung, Google, and IBM are major contributors. Some companies, like Red Hat and Canonical, have built successful businesses around Linux.
The free software licenses encourage businesses to use and sell Linux. A common business model for companies is to charge for support, especially for businesses. Another model is to give away the software for free and make money by selling hardware that runs Linux.
Programming on Linux
Most programming languages work on Linux. The main tools used to build Linux programs are part of the GNU toolchain, which includes the GNU Compiler Collection (GCC). GCC can compile code for languages like C, C++, and Go. Many other popular languages like PHP, Perl, Python, and Java also have versions that run on Linux.
Linux also includes special programming languages for scripting, text processing, and managing the system. These include shell scripts, awk, and sed. Many programs also have their own built-in programming languages.
Most Linux distros support dynamic languages like PHP, Perl, Ruby, and Python. There are also many IDEs (special programs for writing code) available on Linux, like Eclipse and NetBeans. Popular text editors like Vim and GNU Emacs are also widely used.
What Hardware Linux Supports
The Linux kernel can run on a huge variety of hardware, from mobile phones to supercomputers. It works on many different computer architectures, including ARM-based Android smartphones and large IBM Z mainframes. There are even special versions of Linux for less common hardware.
Linux is known for supporting older hardware very well. It keeps standard drivers for a long time, which means old devices can often still work with Linux. Over time, Linux has gotten better at supporting new hardware, so most new devices you buy will likely work with it.
Where Linux is Used
How Popular is Linux?
Many studies show that Linux is growing in popularity. Experts believe the Linux operating system market will grow significantly in the coming years. People like Linux because it's secure, reliable, low-cost, and gives them freedom from being stuck with one company's products.
- Desktops and laptops
- While Microsoft Windows is still the most used operating system on desktop computers, Linux is used by a smaller but growing percentage of users (around 3.7% as of early 2024).
- Web servers
- Linux is incredibly popular for web servers. Studies show that over 96% of the top web servers run Linux. This means that when you visit most websites, they are likely hosted on a Linux server.
- Mobile devices
- Android, which uses the Linux kernel, is the most popular operating system for smartphones. As of 2023, about 68% of mobile devices accessing websites use Android. It's also very popular on tablets.
- Film production
- Linux has been the top choice in the film industry for many years. The movie Titanic (1997) was one of the first major films to use Linux servers. Since then, big studios like DreamWorks Animation, Pixar, and Industrial Light & Magic have switched to Linux. More than 95% of the servers and desktops at large animation and visual effects companies use Linux.
- Use in government
- Many local and national governments are using Linux. For example, the Russian military created its own Linux distribution. The Indian state of Kerala requires all high schools to use Linux on their computers. China uses Linux for its Loongson processors to be independent in technology. In Spain, some regions have developed their own Linux distributions for schools and government offices. Countries like France and Germany are also moving towards using Linux. North Korea's Red Star OS is also based on Fedora Linux.
Copyright and Naming
The Linux kernel is licensed under the GNU General Public License (GPL), version 2. This license means that anyone who shares software based on this code must also make the original code (and any changes) available to others under the same rules. Other important parts of a Linux distribution are also mostly under the GPL, but some use other licenses, like the GNU Lesser General Public License (LGPL), which is a bit more flexible.
Linus Torvalds has said that the Linux kernel will not switch to version 3 of the GPL. He doesn't like some parts of the new license that prevent using the software with digital rights management. Also, it would be very hard to get permission from all the thousands of people who hold copyrights to the code.
A study in 2001 looked at Red Hat Linux 7.1. It found that this distribution had 30 million lines of code. The study estimated that it would have taken about eight thousand years of work for one person to develop it. If this software had been developed by traditional companies, it would have cost around $1.08 billion in 2000. Most of the code (71%) was written in the C programming language.
In the United States, the name Linux is a trademark registered to Linus Torvalds. At first, no one registered it. But in 1994, a person tried to claim the trademark and demand money from Linux distributors. In 1996, Torvalds and others sued him, and in 1997, the case was settled. The trademark is now managed by the Linux Mark Institute (LMI). Torvalds said he trademarked the name only to stop others from using it unfairly. LMI now offers a free license to use the Linux name as part of trademarks.
The Free Software Foundation (FSF) prefers to call the whole operating system GNU/Linux. They see Linux distributions as different versions of the GNU operating system, which Richard Stallman started in 1983. However, the FSF doesn't have a problem with the name Android, even though it also uses the Linux kernel, because GNU software is not part of Android.
Most media and common usage simply call this family of operating systems Linux. Many large Linux distributions, like SUSE Linux and Red Hat Enterprise Linux, also use just "Linux."
See also
In Spanish: GNU/Linux para niños
- Comparison of Linux distributions
- Comparison of operating systems
- Linux kernel version history
- List of Linux distributions
- List of operating systems
- Usage share of operating systems
