Getting down to Basics OPERATING SYSTEM (OS) The person inside my machine is called the operating system (OS). Without the OS, a computer is nothing but a life-less collection of metal, silicon, and dust balls. With the OS, it breaths of life, and is ready to work for you. Different types of computers have different operating systems. Sometimes computers of the same kind have different operating systems. The most common kind is the IBM-compatible and almost all of them use DOS/MSDOS. By Bella Strand Tech Note