High-flying penguinsLinux and open source is driven by passionate people who write best-of-breed software and then release the code to the public so anyone can use it, without any strings attached. (Well, there is one string attached and that\u2019s licence.)Who are these people? These heroes of the Linux world, whose work affects all of us every day. Allow me to introduce you.Klaus KnopperImage by Swapnil BhartiyaKlaus Knopper, an Austrian developer who lives in Germany, is the founder of Knoppix and Adriana Linux, which he developed for his blind wife.Knoppix holds a very special place in heart of those Linux users who started using Linux before Ubuntu came along. What makes Knoppix so special is that it popularized the concept of Live CD. Unlike Windows or Mac OS X, you could run the entire operating system from the CD without installing anything on the system. It allowed new users to test Linux on their systems without formatting the hard drive. The live feature of Linux alone contributed heavily to its popularity.Lennart PotteringImage by F\u00f3rum Internacional Software Live\/FlickrLennart Pottering is yet another genius from Germany. He has written so many core components of a Linux (as well as BSD) system that it\u2019s hard to keep track. Most of his work is towards the successors of aging or broken components of the Linux systems.Pottering wrote the modern init system systemd, which shook the Linux world and created a rift in the Debian community.While Linus Torvalds has no problems with systemd, and praises it, he is not a huge fan of the way systemd developers (including the co-author Kay Sievers,) respond to bug reports and criticism. At one point Linus said on the LKML (Linux Kernel Mailing List) that he would never work with Sievers.Lennart is also the author of Pulseaudio, sound server on Linux and Avahi, zero-configuration networking (zeroconf) implementation.Jim Zemlin Image by Meego Com\/FlickrJim Zemlin isn't a developer, but as founder of The Linux Foundation he is certainly one of the most important figures of the Linux world.In 2007, The Linux Foundation was formed as a result of merger between two open source bodies: the Free Standards Group and the Open Source Development Labs. Zemlin was the executive director of the Free Standards Group. Post-merger Zemlin became the executive director of The Linux Foundation and has held that position since.Under his leadership, The Linux Foundation has become the central figure in the modern IT world and plays a very critical role for the Linux ecosystem. In order to ensure that key developers like Torvalds and Kroah-Hartman can focus on Linux, the foundation sponsors them as fellows.Zemlin also made the foundation a bridge between companies so they can collaborate on Linux while at the same time competing in the market. The foundation also organizes many conferences around the world and offers many courses for Linux developers.People may think of Zemlin as Linus Torvalds' boss, but he refers to himself as "Linus Torvalds' janitor."Greg Kroah-HartmanImage by Coscup\/FlickrGreg Kroah-Hartman is known as second-in-command of the Linux kernel. The \u2018gentle giant\u2019 is the maintainer of the stable branch of the kernel and of staging subsystem, USB, driver core, debugfs, kref, kobject, and the sysfs kernel subsystems along with many other components of a Linux system.He is also credited for device drivers for Linux. One of his jobs is to travel around the globe, meet hardware makers and persuade them to make their drivers available for Linux. The next time you plug some random USB device to your system and it works out of the box, thank Kroah-Hartman. (Don't thank the distro. Some distros try to take credit for the work Kroah-Hartman or the Linux kernel did.)Kroah-Hartman previously worked for Novell and then joined the Linux Foundation as a fellow, alongside Linus Torvalds.Kroah-Hartman is the total opposite of Linus and never rants (at least publicly). One time there was some ripple was when he stated that Canonical doesn\u2019t contribute much to the Linux kernel.On a personal level, Kroah-Hartman is extremely helpful to new developers and users and is easily accessible.Linus TorvaldsImage by Swapnil BhartiyaNo collection of Linux heroes would be complete without Linus Torvalds. He is the author of the Linux kernel, the most used open source technology on the planet and beyond. His software powers everything from space stations to supercomputers, military drones to mobile devices and tiny smartwatches. Linus remains the authority on the Linux kernel and makes the final decision on which patches to merge to the kernel.Linux isn't Torvalds' only contribution open source. When he got fed-up with the existing software revision control systems, which his kernel heavily relied on, he wrote his own, called Git. Git enjoys the same reputation as Linux; it is the most used version control system in the world.Torvalds is also a passionate scuba diver and when he found no decent dive logs for Linux, he wrote his own and called it SubSurface.Torvalds is well known for his rants and once admitted that his ego is as big as a small planet. But he is also known for admitting his mistakes if he realizes he was wrong.