Also on these boards
The Apple /// was designed to be a business machine. It was partly compatible with the Apple II (thanks to a few options in the operating system). It used a powerful memory management system and worked under SOS (Sophisticated Operating System) which was a great, device -independent, operating system. This OS was the "ancestor" of ProDOS (the "professional" Apple operating system) and some parts of this system were used later in the Lisa and Macintosh OSs.