The Apple III (stylized as apple ///) is a business-oriented personal computer that was produced by Apple Computer and released in 1980. It was intended as the successor to the Apple II with features business users wanted—a full typewriter-style keyboard with upper and lowercase letters, multi-directional cursor keys and an 80-column display—but it failed in the market. It uses Apple's proprietary Sophisticated Operating System (SOS).
Designed by Wendell Sander, the Apple III was announced on May 19, 1980, and released in late November that year. Serious stability issues required a design overhaul and a recall of the first 14,000 machines produced. It was formally reintroduced on November 9, 1981, but damage to the computer's reputation had already been done. An updated version was released in December 1983 as the Apple III Plus.
An estimated 65,000 to 75,000 Apple III computers were sold. The Apple III Plus brought this up to approximately 120,000. The original model was discontinued on April 24, 1984, and the Plus in September 1985. The III's failure led Apple to reevaluate its plan to phase out the Apple II, and later Apple II models incorporate some technologies of the Apple III. Steve Wozniak stated that the primary reason for the Apple III's failure was that the system was designed by Apple's marketing department, unlike Apple's previous engineering-driven projects.
Overview Design Steve Wozniak and Steve Jobs expected hobbyists to purchase the Apple II; however, because of VisiCalc and Disk II, small businesses purchased 90% of the computers. The Apple III was designed to be a business computer and successor. Though the Apple II contributed to the inspirations of several important business products, such as VisiCalc, Multiplan, and Apple Writer, the computer's hardware architecture, operating system, and developer environment were limited. Apple management intended to clearly establish market segmentation by designing the Apple III to appeal to the 90% business market, leaving the Apple II to home and education users. Management believed that "once the Apple III was out, the Apple II would stop selling in six months", Wozniak said.
The Apple III is powered by a 2-megahertz Synertek 6502A or 6502B 8-bit CPU (operating effectively between 1.4 and 1.8 MHz due to video or memory refresh cycles) and, like some of the later machines in the Apple II family, uses bank switching techniques to address memory beyond the 6502's traditional 64 KB limit, up to 256 KB in the III's case. Third-party vendors produced memory upgrade kits that allow the Apple III to reach up to 512 KB of random-access memory (RAM). Other Apple III built-in features include an 80-column, 24-line display with upper and lowercase characters, a numeric keypad, dual-speed (pressure-sensitive) cursor control keys, 6-bit (DAC) audio, and a built-in 140-kilobyte 5.25-inch floppy disk drive. Graphics modes include 560x192 in black and white, and 280x192 with 16 colors or shades of gray. Unlike the Apple II, the Disk III controller is part of the logic board.
The Apple III is the first Apple product to allow the user to choose both a screen font and a keyboard layout: either QWERTY or Dvorak. These choices cannot be changed while programs were running. This was unlike the Apple IIc, which has a keyboard switch directly above the keyboard, allowing the user to switch on the fly.
Software
The Apple III introduced an advanced operating system called Apple SOS, pronounced "apple sauce". Its ability to address resources by name allows the Apple III to be more scalable than the Apple II's addressing by physical location such as PR#6 and CATALOG, D1. Apple SOS allows the full capacity of a storage device to be used as a single volume, such as the Apple ProFile hard disk drive, and it supports a hierarchical file system. Some of the features and code base of Apple SOS were later adopted into the Apple II's ProDOS and GS/OS operating systems, as well as Lisa 7/7 and Mac OS.
With a starting price of $4,340 (equivalent to $17,356 as of 2024) and a maximum price of $7,800 (equivalent to $31,194 as of 2024), the Apple III was more expensive than many of the CP/M-based business computers that were available at the time. Few software applications other than VisiCalc are available for the computer; according to a presentation at KansasFest 2012, fewer than 50 Apple III-specific software packages were ever published, most shipping when the III Plus was released. However this number is proven to be wildly incorrect, given the manual 'RESOURCE GUIDE: Of Apple /// and Apple /// Plus Software and Hardware' published and released by Apple Computer, Inc. in May 1984 lists in excess of 500+ software packages produced by many and varied publishers. Given software publishers and specialised hardware manufacturers such as On-Three, Inc. produced products for the Apple III well in to the late 90s, in excess of 500 products can also be seen as way too conservative.
Because Apple did not view the Apple III as suitable for hobbyists, it did not provide much of the technical software information that accompanies the Apple II. Originally intended as a direct replacement to the Apple II, it was designed to be backward compatible with Apple II software. However, since Apple did not want to encourage continued development of the II platform, Apple II compatibility exists only in a special Apple II Mode which is limited in its capabilities to the emulation of a basic Apple II Plus configuration with of RAM.
Special chips were intentionally added to prevent access from Apple II Mode to the III's advanced features such as its larger amount of memory.
Peripherals The Apple III has four expansion slots, a number that inCider in 1986 called "miserly", also saying Apple II cards are compatible but risk violating government RFI regulations, and require Apple III-specific device drivers; BYTE stated that "Apple provides virtually no information on how to write them". As with software, Apple provided little hardware technical information with the computer but Apple III-specific products became available, such as one that made the computer compatible with the Apple IIe. Several new Apple-produced peripherals were developed for the Apple III. The original Apple III has a built-in real-time clock, which is recognized by Apple SOS. The clock was later removed from the "revised" model, and was instead made available as an add-on.
Along with the built-in floppy drive, the Apple III can also handle up to three additional external Disk III floppy disk drives. The Disk III is only officially compatible with the Apple III. The Apple III Plus requires an adaptor from Apple to use the Disk III with its DB-25 disk port.
With the introduction of the revised Apple III a year after launch, Apple began offering the ProFile external hard disk system. Priced at $3,499 for 5 MB of storage, it also required a peripheral slot for its controller card.
Backward compatibility The Apple III has the built-in hardware capability to run Apple II software. In order to do so, an emulation boot disk is required that functionally turns the machine into a standard 48-kilobyte Apple II Plus, until it is powered off. The keyboard, internal floppy drive (and one external Disk III), display (color is provided through the 'B/W video' port) and speaker all act as Apple II peripherals. The paddle and serial ports can also function in Apple II mode, however with some limitations and compatibility issues.
Apple engineers added specialized circuitry with the sole purpose of blocking access to its advanced features when running in Apple II emulation mode. This was done primarily to discourage further development and interest in the Apple II line, and to push the Apple III as its successor. For example, no more than of RAM can be accessed, even if the machine has of RAM or higher present. Many Apple II programs require a minimum of of RAM, making them impossible to run on the Apple III. Similarly, access to lowercase support, 80 columns text, or its more advanced graphics and sound are blocked by this hardware circuitry, making it impossible for even skilled software programmers to bypass Apple's lockout. A third-party company, Titan Technologies, sold an expansion board called the III Plus II that allows Apple II mode to access more memory, a standard game port, and with a later released companion card, even emulate the Apple IIe.
Certain Apple II slot cards can be installed in the Apple III and used in native III-mode with custom written SOS device drivers, including Grappler Plus and Liron 3.5 Controller.
Revisions
After overheating issues were attributed to serious design flaws, a redesigned logic board was introduced in mid-December 1981 – which included a lower power supply requirement, wider circuit traces and better-designed chip sockets. The $3,495 revised model also includes 256 KB of RAM as the standard configuration. The 14,000 units of the original Apple III sold were returned and replaced with the entirely new revised model.
Apple III Plus Apple discontinued the III in October 1983 because it violated FCC regulations, and the FCC required the company to change the redesigned computer's name. It introduced the Apple III Plus in December 1983 at a price of US$2,995. This newer version includes a built-in clock, video interlacing, standardized rear port connectors, 55-watt power supply, 256 KB of RAM as standard, and a redesigned, Apple IIe-like keyboard.
Owners of the Apple III could purchase individual III Plus upgrades, like the clock and interlacing feature, and obtain the newer logic board as a service replacement. A keyboard upgrade kit, dubbed "Apple III Plus upgrade kit" was also made available – which included the keyboard, cover, keyboard encoder ROM, and logo replacements. This upgrade had to be installed by an authorized service technician.
Design flaws
According to Wozniak, the Apple III "had 100 percent hardware failures". Former Apple executive Taylor Pohlman stated that:
Jobs insisted on the idea of having no fan or air vents, in order to make the computer run quietly. He would later push this same ideology onto almost all Apple models he had control of, from the Apple Lisa and Macintosh 128K to the iMac. To allow the computer to dissipate heat, the base of the Apple III was made of heavy cast aluminum, which supposedly acts as a heat sink. One advantage to the aluminum case was a reduction in radio frequency interference, a problem which had plagued the Apple II series throughout its history. Unlike the Apple II, the power supply was mounted – without its own shell – in a compartment separate from the logic board. The decision to use an aluminum shell ultimately led to engineering issues which resulted in the Apple III's reliability problems. The lead time for manufacturing the shells was high, and this had to be done before the motherboard was finalized. Later, it was realized that there was not enough room on the motherboard for all of the components unless narrow traces were used.
Many Apple IIIs were thought to have failed due to their inability to properly dissipate heat. inCider stated in 1986 that "Heat has always been a formidable enemy of the Apple ///", and some users reported that their Apple IIIs became so hot that the chips started dislodging from the board, causing the screen to display garbled data or their disk to come out of the slot "melted". BYTE wrote, "the integrated circuits tended to wander out of their sockets". It has been rumored Apple advised customers to tilt the front of the Apple III six inches above the desk and then drop it to reseat the chips as a temporary solution. Other analyses blame a faulty automatic chip insertion process, not heat.