The Atari 8-bit computers, formally launched as the Atari Home Computer System, are a series of home computers introduced by Atari, Inc., in 1979 with the Atari 400 and Atari 800. The architecture is designed around the 8-bit MOS Technology 6502 CPU and three custom coprocessors which provide support for sprites, smooth multidirectional scrolling, four channels of audio, and other features. The graphics and sound are more advanced than most of its contemporaries, and video games are a key part of the software library. The 1980 first-person space combat simulator Star Raiders is considered the platform's killer app.