Atari originally unveiled the 7800 ProSystem in 1984, developed in collaboration with General Computer Corporation, but the sale of Atari’s consumer division to Jack Tramiel interrupted its launch. The console finally reached the United States market on a broad basis in 1986. It used the MARIA graphics chip and retained direct compatibility with the Atari 2600 cartridge library, an important advantage over the earlier Atari 5200. Its history is particularly unusual because the hardware was essentially ready two years before Atari effectively brought it to market.