Editing Apple III (section)

==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.{{r|byte198501}} 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 are limited.<ref name="apple2hist">{{Cite web |title=The Apple III SOS Reference Manual Vol 1 |url=https://archive.org/details/apple-iii-sos-reference-manual-vol-1/page/n40/mode/1up |url-status=dead |archive-url= |archive-date= |access-date= |website=Internet Archive}}</ref> 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.<ref name="byte198501">{{cite magazine |title=The Apple Story / Part 2: More History and the Apple III |magazine=[[Byte (magazine)|BYTE]] |publisher=UBM Technology Group|location=United States|volume=10|number=1|issn=0360-5280|oclc=637876171|date=January 1985 |author-last1=Williams |author-first1=Gregg |author-last2=Moore |author-first2=Rob |page=167 |type=interview |url=https://archive.org/details/198501_byte_magazine_vol_10_01_through_the_hourglass_pdf__mlib/page/174/mode/2up}}</ref>

The Apple III is powered by a 2 [[megahertz]] [[Synertek]] [[MOS Technology 6502|6502A]] or 6502B<ref>{{cite book |author1= |title=Apple III Owner's Guide |author2= |publisher=Apple Computer Inc. #A3L0001 |year=1981 |edition=3rd |pages=152–153 |language=English}}</ref><ref>{{Cite book |title=Apple III Benutzer Handbuch |publisher=[[Apple Inc.|Apple Computer International]] |year=1981 |pages=151 |language=de |trans-title=Apple III User Manual}}</ref>  [[8-bit]] [[central processing unit|CPU]] (operating effectively between 1.4 and 1.8&nbsp;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&nbsp;KB limit, up to 256&nbsp;KB in the III's case. Third-party vendors produced memory upgrade kits that allow the Apple III to reach up to 512&nbsp;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 ([[digital-to-analog converter|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 [[disk controller|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 keyboard layout|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===
[[File:Desktop Computer - The Future for Medicine (FDA 095) (8249708093).jpg|thumb|An advertisement for access to health information through the Apple III]]

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 <code>PR#6</code> and <code>CATALOG, D1</code>. 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 [[codebase|code]] base of Apple SOS were later adopted into the Apple II's [[Apple ProDOS|ProDOS]]<ref>{{cite book|title=Beneath Apple ProDOS|author1=Don Worth|author2=Pieter Lechner|publisher=Quality Software|year=1985|pages=2-4, 4-1, 6-12, E-3|isbn=0-912985-05-4}}</ref> and [[Apple GS/OS|GS/OS]] operating systems, as well as [[Apple Lisa|Lisa 7/7]] and [[Classic Mac OS|Mac OS]].{{Citation needed|date=December 2016}}

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.<ref name="avuqmb" /> Few software applications other than VisiCalc are available for the computer;{{r|moore198209}} 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.<ref name="kansasfest2012">{{Cite AV media |url=https://www.youtube.com/watch?v=St08mKEG2EM#t=31m42s | archive-url=https://ghostarchive.org/varchive/youtube/20211122/St08mKEG2EM| archive-date=2021-11-22 | url-status=live|title=Apple III: A Closer Look |date=May 25, 2012 |last=Maginnis |first=Mike |via=YouTube |time=31:42}}{{cbignore}}</ref> 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.<ref name="moore198209" /> 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 [[emulator|emulation]] of a basic Apple II Plus configuration with {{val|48|ul=kB}} 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.<ref name="byte198501" />

===Peripherals===
The Apple III has four expansion slots, a number that ''inCider'' in 1986 called "miserly".,<ref name="obrien198609">{{cite magazine |last=Obrien |first=Bill |date=September 1986 |title=And II For All |magazine=inCider |url=https://archive.org/stream/inCider_1986-09 |access-date=July 2, 2014| pages=[https://archive.org/stream/inCider_1986-09#page/n37/mode/2up 38], [https://archive.org/stream/inCider_1986-09#page/n91/mode/2up 94–95]}}</ref> also saying Apple II cards are compatible but risk violating government [[electromagnetic interference|RFI]] regulations, and require Apple III-specific [[device driver]]s; ''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<ref name="moore198209" /> but Apple III-specific products became available, such as one that made the computer compatible with the [[Apple IIe]].<ref name="obrien198609" /> 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.<ref>{{cite web | url=http://support.apple.com/kb/TA31434 | title=Archived - Floppy Disk Drives: Apple III Plus External Drive Adapter | work=Apple | date=February 19, 2012 | access-date=November 23, 2013 | archive-date=December 2, 2013 | archive-url=https://web.archive.org/web/20131202235027/http://support.apple.com/kb/TA31434 | url-status=live }}</ref>

With the introduction of the revised Apple III a year after launch, Apple began offering the [[Apple ProFile|ProFile]] external hard disk system.<ref name = "bott" /> Priced at $3,499 for 5&nbsp;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 (game controller)|paddle]] and [[serial port]]s 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 {{nowrap|48 KB}} of RAM can be accessed, even if the machine has {{nowrap|128 KB}} of RAM or higher present. Many Apple II programs require a minimum of {{nowrap|64 KB}} 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===
[[File:Apple III+.jpg|thumb|Apple III Plus]]

After overheating issues were attributed to serious design flaws, a redesigned logic board was introduced in mid-December 1981{{sfn|Linzmayer|2004|pp=41–43}} – which included a lower power supply requirement, wider [[signal trace|circuit traces]] and better-designed chip sockets.<ref name="bott">{{cite web|url=http://applemuseum.bott.org/sections/computers/III.html|title=Apple III|website=Bott.org|access-date=August 2, 2009|archive-date=September 28, 2011|archive-url=https://web.archive.org/web/20110928005535/http://applemuseum.bott.org/sections/computers/III.html|url-status=live}}</ref> The $3,495 revised model also includes 256&nbsp;KB of RAM as the standard configuration.<ref name="bott" /> 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 [[Federal Communications Commission|FCC]] regulations, and the FCC required the company to change the redesigned computer's name.<ref name="maceiie19840409" /><ref name="shea19840123">{{cite magazine | url=https://books.google.com/books?id=fC4EAAAAMBAJ&pg=PA17 | title=Apple releases overhauled III as the III Plus | magazine=[[InfoWorld]] |volume=6|issue=4|issn=0199-6649|oclc=923931674|publisher=IDG|location=United States| date=January 23, 1984 | access-date=February 9, 2015 | last=Shea | first=Tom | page=17}}</ref> It introduced the '''Apple III Plus''' in December 1983 at a price of US$2,995. This newer version includes a built-in clock, [[interlaced video|video interlacing]], standardized rear port connectors, 55-watt power supply, 256&nbsp;KB of RAM as standard, and a redesigned, Apple IIe-like keyboard.<ref name="bott" /><ref name="shea19840123" />

Owners of the Apple III could purchase individual III Plus upgrades, like the clock and interlacing feature,<ref name="shea19840123" /> 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 [[read-only memory|ROM]], and logo replacements. This upgrade had to be installed by an authorized service technician.