What does Dos Mean?

Uno, dos, tres…one, two, three. As it relates to computers, the acronym, DOS means Disk Operating System which was an early operating system (OS) for personal computers. At one time, MS DOS was the most widely used OS. It was command driven vs the graphic user interface (gui) that we use today. For example, to delete a file, at the command prompt, you would type ‘del filename + Enter’.