Wikipedia
Atarisoft was a brand name used by Atari, Inc in 1983 and 1984 to market video games they published for home systems made by their competitors. Each platform had a specific color attributed by Atarisoft for its game packages. For example, video games sold for the Commodore 64 came up in green packages, games for the Texas Instruments TI-99/4A in yellow, games for the IBM PC in blue, and so on. Despite being in existence for less than two years, Atarisoft had a huge video game library with dozens of game versions being released for various home computers and consoles. Almost all of the Atarisoft titles were produced by third-party software companies, as Atari only developed for their own systems.
The Atarisoft label did not bear Atari's popular "fuji" logo nor the official logos of the games, rather,the game names were written in a different typeface (popularly called "Futuri Extra Bold [non-italic]"). The Atarisoft brand was used on game boxes, manuals; and advertising, but the name that appeared on the title screen of these games was generally that of Atari, not Atarisoft.
The Atarisoft label as utilized by Atari Inc. was discontinued shortly after Warner Communications sold Atari Inc's consumer division to Jack Tramiel in 1984. Many additional titles were in production at the time. Most of these went unreleased although a few were eventually released by other companies.
The new Atari Corp. initially used the Atarisoft brand as well. Several Atari 8-bit software titles (both game and non-game) were published by Atari UK and Atari France using the Atarisoft label in 1985. Atari did not use the Atarisoft label again after 1985.