In 1982 Atari's Home Computer Division (HCD) introduced the new replacement computer to its aging Atari 400/800 line. The new computer brought to Atari's home computers line a high-tech and sleek low profile modern look. The case design and the "XL Look" were created by Regan Cheng of Atari's Industrial Design group. The all new design took the 7 separate boards that made up the Atari 800 (Main, Power, CPU, OS and 3 16K Memory boards) and integrated them into a single motherboard with 64K of memory. The system also brought with it probably "THE" best keyboard for any Atari system.
The system featured many new internal and external enhancements. Some of the obvious ones were the new Function keys and built-in HELP key that programmers could incorporate their usage into future programs. The tangle of wires from the system were now out of the back making for a clean and uncluttered arrangement. The cartridge port and controller jacks were now on the left side of the system. The new OS was designed for a new era of SIO "Plug n Play" devices to automatically load their device drivers and even on-board applications right into the 1200XL memory, also an International Character Set and built-in Diagnostic features were now part of the system. Other OS enhancements were included as well.
However the downside was that many programs by both 3rd party companies and even Atari itself were incompatible with this new OS in the machine. The loss of 2 of the 4 original controller jacks from the earlier Atari 400/800 systems didn't seem like much of a big deal to the 1200XL engineers, however the end users did seem to mind. The system was supposed to have a better video display output signal, however to most end users, the system appeared to have a fuzzier display then the Atari 800. The true sticking point for consumers: No expansion whatsoever.