Originally released in 1977, the Atari 2600 (formally known as the Atari VCS) was one of the first home gaming systems to use microprocessor based hardware and cartridges. By the time production finished at the end of 1991, Atari had sold approximately 40 million Atari 2600 units. Many popular games were produced including Pacman, Breakout, Donkey Kong and Pitfall leading to a large selection of Atari 2600 roms being available today.