Usually when people refer to Linux, they are referring to Linux the kernel, and not the operating system. Linux enthusiast Felix Gardner walks you through how Linux functions as a kernel for an OS of a Linux distribution. When people install Linux they are usually talking about an operating system that uses Linux as the kernel. The kernel was developed by Linus Torvalds in 1991 and a bunch of people started contributing to it. The rest of the operating system is GNU which is a recursive acronym for GNU NOT UNIX. GNU is a whole host of the software that makes up the entire operating system except for the kernel. The beginning of GNU dates back to 1983 when Richard Stallman decided to make a UNIX like operating system. UNIX was becoming closed source and Richard wanted to access the software, so he could make changes and manipulate a computer however he wanted. He believed that people should be able to access the software on their computers. GNU has four essential freedoms: Freedom 0 - The freedom to run the program as you wish, for any purpose. Freedom 1 - The freedom to study how the program works, and change it so it does your computing as you wish. Access to the source code is a precondition for this. Freedom 2 – The freedom to redistribute copies so you can help your neighbor. Freedom 3 - The freedom to distribute copies of your modified versions to others. By doing this you can give the whole community a chance to benefit from your changes. Access to the source code is a precondition for this. Felix walks you through the subtle difference between free software and open software. He sheds light on the fact that some freeware software is not actually free.