Apple SOS

Apple SOS, whose name stood for Sophisticated Operating System and was pronounced like the word sauce, was the primary operating system Apple Computer built for the Apple III. It was released in October 1980 and took its internal name from the Apple III's own code name, Sara. SOS was a single tasking, single user system with a monolithic kernel and a text mode interface, offering programmers file, device, memory and utility programming interfaces and a menu driven utility program for end users. It supported both character devices such as keyboards and serial ports and block devices such as disk drives using 512 byte blocks. Steve Wozniak later called it the finest operating system on any microcomputer, even while criticizing the Apple III's hardware. It is no longer maintained and its source was never released publicly. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/