In 1991, a Finnish student posted to a mailing list something along the lines of: “I’m making an operating system, it probably won’t be anything big.” He released the source code openly for anyone to use, modify, and contribute to. What happened next is the largest collaborative software project in history.
Today that project has over 30 million lines of code, contributions from Google, Intel, Red Hat, IBM, and thousands of independent developers. And it runs on 90% of the world’s servers, the phone in your pocket, the 500 fastest supercomputers on the planet, and smart refrigerators.
No installation walkthrough here. That’s for the next article. The focus now is understanding what Linux really is and why it’s everywhere.
What Linux really is
Linux is not an operating system. Linux is a kernel, the core of the system, the layer that sits between the hardware and the rest of the software. The kernel decides how memory is allocated, how processes run, how the disk is accessed, how the network functions. The hardware doesn’t know how to execute a Python program or open a browser. The kernel is the translator between what the software requests and what the hardware does.
What most people call Linux (Ubuntu, Fedora, Arch, Debian) is actually a distribution. A distro takes the Linux kernel and packages it together with a graphical interface, command-line tools, a package manager, and everything else that forms a usable system. The distro is the car. The kernel is the engine.
This distinction matters because it explains why there are hundreds of Linux “versions”, why Android is Linux but doesn’t look like Linux, and why servers run Linux with no graphical interface at all. The kernel is the common denominator. What changes is everything built on top of it.
Where Linux runs
Servers and cloud
Over 90% of internet servers run Linux. AWS, Google Cloud, Azure, all major cloud providers use Linux underneath. When you access any relevant web service, a Linux server almost certainly responded.
It’s the system of choice for infrastructure for concrete reasons: it’s free (no per-server license), it’s stable (Linux systems running for years without rebooting are common), it’s lightweight (you control exactly what’s installed, with no unnecessary software consuming resources), and it has decades of battle-testing in production.
Android
Android is based on the Linux kernel. Every time you use your phone, the Linux kernel is managing memory, processes, networking, and storage. It’s not a traditional Linux distro (it doesn’t have the same commands, doesn’t have the same desktop environment), but the kernel underneath is the same 1991 project.
This means Linux is in the pocket of over 3 billion people, even if none of them know it.
Steam Deck and gaming
Valve bet on Linux to run Windows games via Proton, a compatibility layer that translates Windows calls to Linux in real time. The Steam Deck runs SteamOS (based on Arch Linux). AAA games that were previously Windows-exclusive run on Linux via Proton with comparable performance.
This matters because gaming was historically the last barrier keeping users on Windows. That barrier is being torn down.
Supercomputers and scientific research
100% of the 500 fastest supercomputers in the world run Linux. From NASA to CERN, through climate research centers and particle physics simulation. When you hear about a scientific discovery that depended on massive computing, Linux is running underneath.
The reason is the same as for servers: control, performance, and the ability to customize the system down to the kernel level for specific use cases.
Embedded systems and IoT
Routers, smart TVs, security cameras, industrial systems, cars, and smart refrigerators. Linux runs on devices with minimal resources because it’s modular and can be compiled to include only what’s needed for that specific hardware. An embedded Linux can occupy less than 1MB.
Personal desktop
The smallest market share of the five, but growing consistently. Developers, sysadmins, and tech enthusiasts choose Linux as their primary system for control over the system, privacy (no mandatory telemetry), proximity to development tools, and because the terminal on Linux is a first-class citizen, not a secondary feature.
Why this matters for people working in tech
If you work with backend, DevOps, cloud, or security, you will inevitably interact with Linux. It’s not optional. Servers are Linux. Docker containers run on the Linux kernel. CI pipelines run on Linux. Infrastructure tooling assumes Linux as the default environment. Knowing how to navigate a Linux terminal is not a differentiator, it’s a requirement.
The point isn’t that you need to abandon Windows or Mac. The point is that understanding Linux makes you a more complete professional, regardless of where you work. When something breaks on a server (and it will), you need to know what you’re looking at.
For desktop users, the proximity to tooling changes productivity. Everything involving Docker, Vagrant, Kubernetes, and command-line tools in general is more natural in a Linux environment because those tools were built for Linux first.
The next step
Understanding what Linux is and where it runs is the first step. The second is knowing how to use it: which distribution to choose, how to experiment without risk, and the commands that show up in 90% of real situations. That’s the subject of the next article.
References
- Official Linux kernel repository: https://kernel.org
- Distrowatch (distribution list): https://distrowatch.com
- Top500 (supercomputer rankings): https://top500.org