The Atari XL (eXtended Line) range would replace the aging 400 and 800 computer systems.  The first new XL system to launch was the 1200XL in 1983, but it only saw a North American roll-out.  The computer was plagued by problems, noticeably in its "fuzzy" video output and the lack of backward compatibility with certain software and hardware.  Most frustrating for a new computer was the lack of any expansion options, as the new unit was totally closed with no access to the system bus and no memory expansion options.

Atari was also having other problems, which put additional pressure on the computer division and their senior managers.  With the company already loosing money, the failure of the 1200XL had to be rectified quickly, and through the New York and Sunnyvale offices, new systems were hastily revised.  Back from the drawing board, the new systems were revealed in late 1983 as the low-end 600XL, and the higher-end 800XL.  A 1400XL and 1450XLD were also planned for release shortly after, in early 1984.

The 600XL had 16Kb of RAM (expandable to 64Kb with the 1064 Expansion module) and the 800XL came with 64Kb as standard and a slightly larger case.  Both machines had the same functionality, and were better received by the consumer than the troublesome 1200XL.  The XL line had a shaky start, but soon recovered, as the new 600XL and 800XL began rolling off the production lines and prepared for sale outside the U.S., unlike the 1200XL.

The software compatibility problems were largely taken care of, and the cartridge slot had been redesigned and replaced to the top of the case, solving the physical cartridge slot issues on the 1200XL.  The 600XL and 800XL retained the advance styling and design of the 1200XL, probably as much for cost reasons than anything else.

From a users perspective, the 600XL and 800XL were simply replacements for the 400 and 800, and that was basically true.  So, what was so new about them?  The answer is "not a lot", and although internal components had been revised, these were the "bread and butter" line for the Atari computer division.  What would really show off the new XL line would be the promised 1400XL and 1450XLD computers.

The 1400XL had, in addition to the standard functionality of the 600XL and 800XL; a fully functional speech synthesiser, a built-in 300 baud modem and additional programmable function keys.  The XLD version would have the addition of a double-sided double density 5.25" disk drive.  Unfortunately, only a small number of 1450XLD's were manufactured, and the 1400XL was cancelled completely.  Even the proposed 1600XL featuring IBM compatibility would never see the light of day.

The XL line was cancelled in its entirety in late 1984 after the company was sold to Jack Tramiel.  It's replacement would be the XE range which would launch in 1985.