DOS? On a Mac? Yup. You may think that DOS was a precursor to Windows, but Apple had its own version for the Apple II and, as with the PC-based sibling, it was originally a text-based environment devoid of a graphical user interface (GUI).
The release of Apple DOS was a landmark moment in the life of the Apple II as it meant the machine could finally jettison its tape-based storage for a faster disk-based setup, allowing users to access their data almost instantaneously on dual-sided 5.25in media.
Apple DOS pre-dates 1984’s Macintosh launch. The first edition, version 3.1, was shipped in 1978 and the last, version 3.3, just two years later, although Apple did maintain the code for a further three years until shortly before the Macintosh shipped.
It was succeeded by ProDOS, also from Apple, which debuted in October 1983 and remained on sale just short of a decade. This introduced support for higher capacity 3.5in disks and, in the ProDOS 16 build that ran on the Apple IIGS, a GUI similar to the one we came to know (and love) on the Macintosh itself.
For more Apple history read:
Apple timeline in pictures