Mac System Software 1.x

Mac System Software 1.0 was released on 1984-01-24 for the Macintosh now called the Macintosh 128K or Mac128K. There have been 3 leaked builds of Mac System Software 1.0, one of the builds is on a Twiggy floppy disk which was found alongside a Twiggy Macintosh. The Twiggy floppy disk is a floppy disk that was designed by Apple and was very faulty. Mac System Software 1.1 was an update to Mac System Software 1.0 released on 1984-12-29.