 The three versions were very different, the 4k version lacked string variables and functions and used a 32-bit floating point format, the 8k version added string functionality, and the 12k version added more functions, 64-bit variables, and other features.By the time the Atari machines were being designed, RAM was becoming much less expensive.Microsoft took advantage of this by producing a single version for the 6502, most closely resembling the 8k version from the 8080.