Fundamentals of Computing - Lesson 1 - The Operating System

Nowadays, youngsters think Windows or MacOS (or sometimes Linux) when you talk about computers. The mouse and little icons have become so commonplace that no one considers that there was actually a time when we didn't have these little icons. Back in those days we had an operating system based on commands entered on a command line. That system was MS-DOS, licensed by IBM for their own machines as PC-DOS, and even 'copied' by a competitor as DR-DOS.