Apple III

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Apple III

Release date	May 1980
Introductory price	$7,800[1]
Discontinued	April 1984
Operating system	Apple Sophisticated OS (SOS)
CPU	Synertek 6502A @ 2 MHz
Memory	128 KB, expandable to 512 KB

The Apple III (often rendered as Apple ///) is a personal computer that was manufactured and sold by Apple. Intended as a computer for the business user market, 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. ^[2] The model was first announced on May 19, 1980, and started shipping the following Autumn.^[3] It was discontinued on April 24, 1984.

Possibly more relevant in the long run was the fact that the Apple III was essentially an enhanced Apple II — newest heir to a line of 8-bit machines dating back to 1976. In 1981, International Business Machines unveiled the IBM Personal Computer (IBM PC) — a completely new 16-bit design soon available in a wide range of inexpensive clones. The business market moved rapidly towards the PC-DOS/MS-DOS platform, eventually pulling away from the Apple 8-bit computer line.^[4] In the end, an estimated 65,000 Apple III computers were sold.^[3] Apple co-founder 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.^[5]

Timeline of Apple II family models

Apple III design

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The Apple III was designed to be a business computer and an eventual successor for the Apple II.^[6] While 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.^[7] The Apple III addressed these weaknesses.

The Apple III was powered by a 1.8 MHz SynerTek 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 256 KB of memory. Third-party vendors also produced memory upgrade kits that allowed the Apple III to reach up to 512 KB. Other Apple III built-in features included an 80-column display with upper and lowercase characters, a numeric keypad, 6-bit (DAC) audio, 16-color graphics, and a built-in 140 KB 5.25" floppy disk drive. Unlike the Apple II, the Disk III controller was built into the logic board.

The Apple III was the first Apple product that allowed the user to choose both a screen font and a keyboard layout:either QWERTY or Dvorak. These choices could not be changed while programs were running, unlike the Apple IIc, which had a keyboard switch directly above the keyboard, allowing switching on the fly.

Software

A major limitation of the Apple II and DOS 3.3 was the way it addressed resources, which forced peripherals to be installed in pre-determined locations (slot 5 and 6 reserved for storage devices, slot 2 reserved for serial communication interfaces, etc.) This forced the user to identify a peripheral by its physical location, such as PR#6, CATALOG,D1, and so on.^[8] The Apple III introduced an advanced operating system called Apple SOS, pronounced "apple sauce". Its ability to address resources by name instead of a physical location allowed the Apple III to be more scalable. Apple SOS also allowed the full capacity of a storage device to be used as a single volume, such as the Apple ProFile hard disk drive. And, Apple SOS supported a hierarchical file system (HFS). Some of the features and code base of Apple SOS made their way into the Apple II's ProDOS and GS/OS operating systems, as well as Lisa 7/7 and Macintosh system software.

The Apple III also introduced a new BASIC interpreter called Apple III Business BASIC, and later an implementation of UCSD Pascal for more structured programming.

Originally intended as a direct replacement to the Apple II series, it was designed for backwards-compatibility of Apple II software in order to migrate users over. However, since Apple did not want to encourage continued development of the II platform, they limited its capabilities to emulate a basic 48 KB Apple II+ configuration, with no access to the III's advanced features, a restriction which actually required custom chips to enforce.

The Apple III had a System Utilities program, which allowed system reconfiguration and file manipulation. Another program, Selector III, was designed to integrate with the System Utilities program and launch various applications. However, Apple decided not to finish this project, and the engineers and writers working on the project bought the right to market Selector III to Apple III owners for a nominal fee. However, another company, Quark Software, developed a competing product, Catalyst, the cruder interface of which was offset by program-switching capabilities and support for copy-protection, which enabled companies to license users to run programs from a hard disk without worrying that their software might be backed up or copied without permission. When Apple decided to bundle Catalyst with its new ProFile hard disk, Quark celebrated, and the Selector III's developers quietly dissolved their company.

Peripherals

Several Apple-produced peripherals were made available because of the Apple III. The original Apple III came with a built-in real-time clock, which was recognized by Apple SOS. The clock was later removed from the "revised" and "Plus" models, and instead was made available as an add-on.

Along with the built-in floppy drive, the Apple III could also handle up to three additional external Disk III floppy disk drives. The Disk III was only officially compatible with the Apple III, although the Apple III was able to use the Apple II's modified Disk II disk drive and vice-versa.

For additional storage, Apple produced the ProFile external hard disk system. The ProFile was not made available until the release of the revised Apple III over a year later.^[9] At a price of US$3499 for 5MB, it also required a peripheral slot for the ProFile controller card.

Revisions

Once the logic board design flaws were discovered, a newer logic board design was produced - which included wider traces and better designed chip sockets.^[9] The revised model also included 256 KB RAM as a standard configuration.^[9] The 14,000 units of the original Apple III sold were returned and replaced with the entirely new revised model.

Apple III Plus

The Apple III Plus was introduced in December 1983, while discontinuing the original III model, at a price of US$2995.^[9] This newer version included a built-in clock, video interlacing, improved ports, and a re-designed keyboard. The keyboard was designed in the style of the earlier beige Apple IIe.^[9]

Owners of the earlier Apple III could 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

Steve Jobs forced on the idea of no fan or air vents - in order to make the computer run quietly. Jobs would later push this same ideology onto almost all Macintosh models he had control of - from the Apple Lisa and Macintosh 128K to the iMac^[10]. To allow the computer to rid of heat, the base of the Apple III was made of heavy cast iron, which supposedly acted as a heat sink. And, unlike the Apple II series, the power supply was stored - without its own shell - in a compartment separate from the logic board.

However, many Apple III's experienced heating issues, allegedly caused by insufficient cooling and inability to dissipate the heat efficiently. To address the heat problem, later Apple III's were fitted with heat sinks. But still, the case design made it impossible for enough heat to escape. Some users stated that their Apple III became so hot that the chips started dislodging from the board, the screen would display garbled data, or their disk would come out of the slot "melted". In a technical bulletin, customers who were experiencing certain problems were instructed to lift the machine 3 inches (76 mm) and drop it in order to re-seat the chips on the logic board. Jerry Manock, the case designer, refuted these case design flaw charges and maintained that the unit adequately dissipated the internal heat, which he proved with various tests.

In the end, Manock was vindicated as the primary culprit turned out to be a major logic board design problem. The logic board used "fineline" technology that was not fully mature at the time, with narrow, closely spaced traces.^[11] When chips were "stuffed" into the board and wave-soldered, solder bridges would form between traces that were not supposed to be connected. This caused numerous short circuits, which required hours of costly diagnosis and hand rework to fix. Apple designed a new circuit board - with more layers and normal-width traces. The new logic board was designed by one designer on a huge drafting board, rather than a costly CAD-CAM system used for the previous board, and it worked.

Earlier Apple III units came with a built-in real time clock, manufactured by National Semiconductor. The hardware, however, would fail after prolonged use. While it was assumed that a vendor would test parts before shipping them, Apple did not perform this level of testing. Apple was soldering chips directly to boards and could not easily change out a bad chip if one was found. Eventually, Apple solved this problem by removing the real-time clock from the Apple III's specification, rather than shipping the Apple III with the clock pre-installed, and sold the peripheral as a level 1 technician add-on.

Commercial failure

For a variety of reasons, the Apple III was a commercial failure. With a starting price between $4,340 to $7,800 US, it was more expensive than many of the CP/M-based business computers that were available at the time.^[1] The Apple III's software library was very limited, and while 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 64 KB RAM or higher, required by a large number of Apple II software titles based on PASCAL), which limited its usefulness.

In the end, Apple had to replace the first 14,000 Apple III machines, free of charge. The customers who had bought them were given brand new machines, with new circuit boards. These did not constitute a new model: it was deemed warranty service. However for new customers in late 1981, Apple "reintroduced" a newly revised system, with twice as much memory (256K RAM),which sold for a much lower introductory price of $3,495. At the same time, Apple also introduced the optional ProFile 5 MB external hard drive.

See also

• List of products discontinued by Apple Inc.

References

External links

• The Ill-Fated Apple III
• Many manuals and diagrams