Apple III

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The Apple III, or Apple /// as it was sometimes styled, was the first completely new computer designed by Apple Computer, Inc. Its predecessor, the better-known Apple II, was designed by Apple co-founder 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", named after Sander's daughter. 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, "Apple /// Business BASIC" (an implementation of UCSD Pascal was also offered for more structured programming). Other features included an 80-column display with upper and lowercase characters, a numeric keypad, support for a real-time clock, 6-bit (DAC) audio, 16-color graphics, hierarchical level file support, and the ability to emulate a 48KB Apple II+. There was a built-in 140K 5.25" floppy disk drive, with up to three additional external "Disk ///" floppy disk drives and a ProFile 5 megabyte hard disk drive available as options. Microsoft developed an add-in "Softcard" that allowed the Apple III to run CP/M, which was actually sold as an Apple product.

The Apple III was powered by a 1.8 MHz 6502B 8-bit CPU and, like some of the more advanced machines in the Apple II family, used bank switching techniques to address up to 256K of memory (512K with a third-party upgrade).

For a variety of reasons, the Apple III was a commercial failure. With a starting price of about $3,500 US, it was more expensive than many of the CP/M-based business computers that were available at the time. The Apple III's software library was very limited, and whilst sold as an Apple II compatible, the emulation that made this possible was intentionally hobbled, thus it could not make use of the advanced III features (specifically 64K RAM or higher, required by a large number of Apple II software titles based on PASCAL) which limited its usefulness. Far more importantly, the machine was plagued by numerous hardware and software bugs. The real time clock, the first in an Apple computer, would fail after prolonged use. At Steve Jobs' insistence, the machine did not include a cooling fan—the metal case was supposed to act as a heat sink, despite not being designed for this purpose. Furthermore, the case itself was too small to properly accommodate the III's internals, and Apple skimped on gold-plating the electrical contacts. The result was an unmitigated disaster. The system would overheat so severely that the motherboard would warp in its tight confines, and thermal expansion would actually push the DIP chips out of their sockets. One popular anecdote about the Apple III is probably better remembered than the machine itself: in a technical bulletin, customers were actually instructed to lift the machine three inches (76 mm) and drop it in order to reseat the chips.

An improved version, the Apple III Plus, was introduced in December 1983. The III Plus fixed the hardware problems of the original III, included 256KB RAM, built-in clock, video interlacing, and featured a keyboard in the style of the Apple IIe. However, not even the new "allow me to reintroduce myself" campaign could salvage the III's reputation. Possibly more relevant in the long run was the fact that the III was essentially an enhanced Apple II—newest heir to a line of 8-bit machines dating back to 1976. The year after the III was originally released, IBM unveiled its PC—a completely new 16-bit design soon available in a wide range of inexpensive clones. The business market moved rapidly towards the IBM machines and, in September 1985, the Apple III line was discontinued, having sold only about 65,000 systems.

Some of the features and codebase of the Sophisticated Operating System made their way into the Apple II's ProDOS and GS/OS operating systems, as well as those of the Lisa and Macintosh.

Although the Apple III shares much of the same technology and traits found in the Apple II series, it is not part of the Apple II family line. Not being a direct Apple II compatible, a special boot disk was required to put it into II emulation mode, much like the Apple Lisa in how it emulated the Macintosh. For this and other reasons, the Apple III can be considered a cousin of the Apple II rather than a member of its family line.

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