In the mainframe era, which ran from the 1950s through the 1970s, the dominant computing operating systems were those of “IBM and the Seven Dwarfs,” typically defined as Burroughs, Univac, NCR, RCA, Control Data, Honeywell, General Electric. The personal computer era, which began in earnest in the 1980s, was briefly led by IBM and its operating system. However, the eventual winners were new entrants, most notably Microsoft, whose Windows operating system and Office software suite ran on nearly every PC in the world, and manufacturers such as Dell, Compaq, and Acer.
