ProDOS was released by Apple to address specific issues relating to connecting peripheral devices such as hard disk drives and third-party non-Disk II floppy disk drives. ProDOS also addressed earlier DOS 3.x problems with hardware interrupt signals, difficulties in assigning memory areas as protected memory, and special function customization. With the release of ProDOS came the end of support for Integer BASIC, which by 1983 had been effectively replaced by AppleSoft BASIC.
ProDOS, unlike earlier Apple DOS 3.x versions, has its developmental roots in SOS, the operating system for the ill-fated Apple III computer released in 1980.
Eventually ProDOS was renamed to ProDOS 8. ProDOS 16 was written to support the new Apple IIgs computer, although it was soon replaced by GS/OS.
Also an Australian based Objectivist site run by the eponymous Prodos Marinakis, here [1], from a more general right wing site here [1]External link