The family of Macintosh operating systems developed by Apple Inc. includes the graphical user interface-based operating systems it has designed for use with its Macintosh series of personal computers since 1984, as well as the related system software it once created for compatible third-party systems. Using only the above description and what you know about the world, "Macintosh operating systems were not used for personal computers until 1984." is definitely correct, incorrect, or inconclusive? 