They created quite a few systems including the 400, the 2600, the 5200, the 7800, Lynx, and Jaguar.
They're best known for creating major games such as Pong, Major Havoc, Battlezone, Crystal Castles and others. Nintendo had ported their version of Donkey Kong to the Atari 2600 in 1981. They also ported there Donkey Kong Jr to the Atari 2600 in 1982 they made these two moves Figuring Atari would be the prominent gaming manufacturer for many years to come, Nintendo requested an expanded contract to port more of their arcade titles, such as Mario Brothers, to the Atari 2600, but were initially refused. They were later accepted however in 1983. This prompted Nintendo to research their own home game console which was released in 1985. Although Mario Brothers was later ported to the Atari 2600 in 1983 anyways as well as ported to the Atari 7800 in 1986 or 1987. Atari is also infamous for being a primary cause of the Video Game Crash of 1983. The company was split up in 1984 and from this point on the home video game part of the company was known as Atari Corporation and it lasted until 1996 before it became a defunct company when the company reverse merged with JTS Inc, becoming a small division, which itself closed when JTS liquidated the IP to Hasbro Interactive in 1998.