Background
The Atari 2600 is a home video game console developed and produced by Atari, Inc. Released in September 1977, it popularized microprocessor-based hardware and games stored on interchangeable ROM cartridges, a format first used with the Fairchild Channel F in 1976. Branded as the Atari Video Computer System (Atari VCS) from its release until November 1982, the VCS was bundled with two joystick controllers, a conjoined pair of paddle controllers, and a game cartridge—initially Combat and later Pac-Man.
(Source : https://en.wikipedia.org/wiki/Atari_2600)
ROM Info
Atari 2600 ROMs should all be in the .a26 or .bin format to run properly on most emulators, including the one on this site.