Atari 8-bit computers

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. The Atari 800 was positioned as a high-end model and the 400 as more affordable. The 400 has a pressure-sensitive, spillproof membrane keyboard and initially shipped with a non-upgradable 8 KB of RAM. The 800 has a conventional keyboard, a second cartridge slot, and allows easy RAM upgrades to 48KB. Both use identical 6502 CPUs at 1.79 MHz (1.77 MHz for PAL versions) and coprocessors ANTIC, POKEY, and CTIA/GTIA. The plug-and-play peripherals use the Atari SIO serial bus, and one of the SIO developers eventually went on to co-patent USB (Universal Serial Bus). The architecture of the Atari 8-bit computers was reused in the 1982 Atari 5200 game console, but games for the two systems are incompatible. The 400 and 800 were replaced by multiple computers with identical core technology and different presentation. The 1200XL was released in early 1983 to supplant the 800. It was discontinued in June 1983, but the industrial design carried over to the 600XL and bestselling 800XL released later the same year. After the company was sold and reestablished, Atari Corporation released the 65XE (called the 800XE in some European markets) and 130XE in 1985. The XL and XE are lighter in construction, have two joystick ports...