Atari Program Exchange

APX was founded by Atari to encourage third party development for the Atari 8-bit computers. Titles were offered via mail order on either cassette or floppy, in simple packaging with generic APX logos and hastily printed, often on dot matrix printers, and photocopied manuals. Several titles such as Caverns of Mars and Eastern Front (1941) were later picked up to be published by Atari and republished on cartridge.