This document discusses GNU/Linux operating systems. It provides background on the GNU project started by Richard Stallman in 1983 to create a free UNIX-like operating system. It also discusses the history of Linux, created by Linus Torvalds in 1991 as a hobby project. Finally, it summarizes some of the advantages of GNU/Linux distributions over other operating systems like Windows and Mac, including being open source, customizable, and providing a variety of free software tools.