Android

Google based its Android mobile operating system on a Linux kernel. At latest estimates, Android is dominating the smartphone market with more than 40 percent market share, according to research firm Canalys. Google’s Chrome OS for laptops is also based on Linux.

Linux now runs the majority of the world’s servers and the biggest Websites, including Amazon, Facebook and Google. IBM’s supercomputer Watson was also Linux-based.

Red Hat, now an S&P 500 company, was one of the first commercial Linux vendors, the first to go public, and is the largest and most successful today. Focusing on enterprise customers, Red Hat has a market capitalization of $7.3 billion, proving that even a free operating system can make money.

In the early days of Linux it was widely assumed that the OS would be relegated to the margins of commercial IT, used perhaps at universities or by smaller businesses looking to save money on IT resources. Instead IT industry giants Dell, IBM, HP, Novell and Oracle have adjusted their strategy to include Linux, design their products to work with the OS, all because their customers say they want to run the platform.

Despite killing off webOS gadgets and looking to get out of the PC business, HP said it plans to keep webOS, a Linux sprout. WebOS will likely be embedded in appliances and cars.

The software contains 14 million lines of code and is protected by more than 520,000 patents, according to a Linux Foundation report. From just 100 developers in 1995, there were over 1,000 in 2010 working on the Linux kernel.

There are hundreds of Linux distributions, where some are very specialized, such as religion-based Linux and the operating system for media centers. Red Hat used to dominate the Linux landscape, but now it’s a little bit more diverse, with Ubuntu accounting for 34 percent and Red Hat at 28 percent, according to a LinuxCon survey.

The upstream collaboration and transparent development in Linux meant that improvements made by one developer could be adopted by others easily. The real-time Linux features that the United States Navy developed for its missile-defense systems have been useful for Wall Street to run the New York Stock Exchange.

Linux made it possible for startups to spin up quickly and cheaply, letting companies get up and running long before the revenue started coming in. Facebook couldn’t have made it using Sun SPARC servers running Solaris at $10 a user, said Red Hat CEO Jim Whitehurst.

Now where can one find Linux? Everywhere, it turns out, as various versions are embedded in car navigation systems, in-flight entertainment systems on planes, stock exchanges, smart electricity meters, televisions, game consoles, cash machines, refrigerators with built-in TVs, and more.