The Atari 400 was released in late 1979 alongside the Atari 800, which were Atari's first entries in the then-new home computer market. Positioned as an entry-level machine, the 400 had a membrane keyboard, no expansion ports like the 800 had, and only had 8 (early units) or 16 KB (most units) of RAM which limited the amount of software it could run. RAM could not be expanded on without a full disassembly of the computer. In addition, the 400 only had RF out whereas the 800 also had a monitor port for improved video quality. The 400 was eventually replaced by the 600XL in late 1983.