The Apple III, or Apple /// as it was sometimes styled, was the first completely new computer designed by Apple Computer, Inc. (the Apple II having been designed by Steve Wozniak prior to the company's incorporation in 1976). Design work on the Apple III started in late 1978 under the guidance of Dr. Wendell Sander. It had the internal code name of "Sara". The Apple III was introduced in May 1980.
The Apple III was designed to be a business computer. It featured an advanced operating system called SOS (the Sophisticated Operating System) and a new BASIC interpreter. Other features included an 80-column display with upper and lowercase characters, a numeric keypad, a real-time clock, a hierarchal file system, and the ability to emulate a 48KB Apple II+. There was a built-in 5¼" floppy disk drive, with a 5 megabyte hard disk drive as an option.
The Apple III was powered by a 2 MHz 6502 8-bit CPU and used banked memory techniques to address up to 128K of memory (the Apple II family was limited to 64K due to that being the limit of its 8-bit address space).
It was a commercial failure, mainly due to the cost, lack of good programs designed specifically for it, and a large number of hardware and software bugss. One popular anecdote about the Apple III is probably better remembered than the machine itself: in a technical bulletin, customers were instructed to lift the machine three inches and drop it – this was supposed to reseat internal DIP chips that had a tendency to come loose.
An improved version, the Apple III Plus, was introduced in December 1983. The III Plus fixed the hardware problems of the original III, included 256K of memory, and featured a keyboard in the style of the Apple IIe. The Apple III line was discontinued four months later.