The Info List - Apple II

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The Apple II
Apple II
(stylized as Apple ][) is an 8-bit home computer, one of the first highly successful mass-produced microcomputer products,[4] designed primarily by Steve Wozniak
Steve Wozniak
( Steve Jobs
Steve Jobs
oversaw the development of the Apple II's foam-molded plastic case[5] and Rod Holt developed the switching power supply).[6] It was introduced in 1977 at the West Coast Computer Faire
West Coast Computer Faire
by Jobs and was the first consumer product sold by Apple Computer, Inc. It is the first model in a series of computers which were produced until Apple IIe
Apple IIe
production ceased in November 1993.[3] The Apple II
Apple II
marks Apple's first launch of a personal computer aimed at a consumer market – branded towards American households rather than businessmen or computer hobbyists.[7] Along with the PET 2001 and the TRS-80, Byte magazine referred to these as the "1977 Trinity" of personal computing.[8] The Apple II
Apple II
had the defining feature of being able to display color graphics, and this capability was the reason why the Apple logo
Apple logo
was redesigned to have a spectrum of colors.


1 History 2 Overview

2.1 Innovation of integrated user interface

3 Case design 4 PCB revisions 5 Display and graphics 6 Sound 7 Languages 8 Third-party devices and applications 9 Reception 10 In popular culture 11 See also 12 References 13 External links

History[edit] By 1976, Steve Jobs
Steve Jobs
had convinced the product designer Jerry Manock (who had formerly worked at Hewlett Packard designing calculators) to create the "shell" for the Apple II
Apple II
– a smooth case inspired by kitchen appliances that would conceal the internal mechanics.[7] The earliest Apple IIs were assembled in Silicon Valley, and later in Texas;[9] printed circuit boards were manufactured in Ireland
and Singapore. The first computers went on sale on June 10, 1977[10][11] with a MOS Technology 6502
MOS Technology 6502
microprocessor running at 1.023 MHz, two game paddles[12] (no longer bundled as of 1980 because they violated FCC regulations[13]), 4 KB of RAM, an audio cassette interface for loading programs and storing data, and the Integer BASIC programming language built into the ROMs. The video controller displays 24 lines by 40 columns of monochrome, upper-case-only (the original character set matches ASCII characters 20h to 5Fh) text on the screen, with NTSC
composite video output suitable for display on a TV monitor, or on a regular TV set by way of a separate RF modulator. The original retail price of the computer was $1,298[14] (with 4 KB of RAM) and $2,638 (with the maximum 48 KB of RAM).[15] To reflect the computer's color graphics capability, the Apple logo
Apple logo
on the casing has rainbow stripes,[16] which remained a part of Apple's corporate logo until early 1998. Perhaps most significantly, the Apple II was a catalyst for personal computers across many industries; it was responsible for opening the doors to software marketed at consumers.[7] Overview[edit] In the May 1977 issue of Byte, Steve Wozniak
Steve Wozniak
published a detailed description of his design; the article began, "To me, a personal computer should be small, reliable, convenient to use and inexpensive".[17] The Apple II
Apple II
used a multiplicity of idiosyncratic engineering shortcuts to save hardware and reduce costs. For example:

Taking advantage of the way that 6502 processor only accesses memory on alternate phases of the clock cycle, the video generation circuitry's memory access on the otherwise unused phase avoids memory contention issues and interruptions of the video stream. This arrangement simultaneously eliminated the need for a separate refresh circuit for the DRAM
chips, as the video transfer accessed each row of the dynamic memory within the timeout period. Rather than use a complex analog-to-digital circuit to read the outputs of the game controller, Wozniak used a simple timer circuit whose period is proportional to the resistance of the game controller, and used a software loop to measure the timer. A single 7  MHz
master oscillator was divided by various ratios to produce all other required frequencies, including the microprocessor clock signals, the video transfer counters, and the color-burst samples.

The text and graphics screens have a complex arrangement (the scanlines were not stored in sequential areas of memory) which is reputedly due to Wozniak's realization that doing it that way would allow for the refresh of the dynamic RAM as a side effect, as described above; it had no cost overhead to have software calculate or look up the address of the required scanline and avoided the need for significant extra hardware. Similarly, in the high-resolution graphics mode, color is determined by pixel position and can thus be implemented in software, saving Wozniak the chips needed to convert bit patterns to colors. This also allows for subpixel font rendering since orange and blue pixels appear half a pixel-width farther to the right on the screen than green and purple pixels.[18] The Apple II
Apple II
at first used data cassette storage like most other microcomputers of the time. In 1978, the company introduced an external ​5 1⁄4-inch floppy disk drive, the Disk II, attached via a controller card that plugs into one of the computer's expansion slots (usually slot 6). The Disk II
Disk II
interface, created by Wozniak, is regarded as an engineering masterpiece for its economy of electronic components.[19][20] The approach taken in the Disk II
Disk II
controller is typical of Wozniak's designs. With a few small-scale logic chips and a cheap PROM (programmable read-only memory), he created a functional floppy-disk interface at a fraction of the component cost of standard circuit configurations. Innovation of integrated user interface[edit] With the Apple I
Apple I
and the Apple II, Wozniak introduced an entirely novel configuration of the microcomputer concept which was immediately adopted as the industry standard, and remains taken for granted to this day—namely the integration of the standard input and output devices (the typewriter-style keyboard and the video display screen) into the computer itself. Until that time, microcomputer devices either had an extremely limited I/O capability—such as perhaps a hex keypad and a 16- or 32-character display, or no built-in user interface at all, following the convention of mainframe and minicomputers in requiring the connection of an external teleprinter unit or visual display terminal to complete a usable system. The cost of such terminals could easily exceed the price of the computer itself. Wozniak's inclusion of an RF output which could connect to the aerial socket of a standard domestic television set enabled users to acquire a complete system without incurring the cost of a video monitor. Case design[edit] Steve Jobs
Steve Jobs
extensively pushed to give the Apple II
Apple II
a case that looked visually appealing and sellable to people outside of electronics hobbyists, rather than the generic wood and metal boxes typical of early microcomputers. The result was a futuristic-looking molded white plastic case. Jobs also payed close attention to the keyboard design and decided to use dark brown keycaps as it contrasted well with the case. The first production Apple IIs had hand-molded cases; these had visible bubbles and other lumps in them from the imperfect plastic molding process, this was soon switched to machine molding. In addition, the initial case design had no vent openings, causing high heat buildup from the PCB and resulting in the plastic softening and sagging. Apple added vent holes to the case within three months of production; customers with the original case could have them replaced at no charge. PCB revisions[edit] The Apple II's PCB underwent several revisions as Steve Wozniak
Steve Wozniak
made modifications to it. The earliest version was known as Revision 0, and the first 6,000 units shipped used it. Later revisions added a color killer circuit to prevent color fringing when the computer was in text mode, as well as modifications to improve the reliability of cassette I/O. Revision 0 Apple IIs powered up in an undefined mode and had garbage on-screen, requiring the user to press Reset. This was eliminated on the later board revisions. Revision 0 Apple IIs could display only four colors, but Wozniak was later able to generate 16 in low-res mode. Original Apple IIs were designed to accommodate either 2104 (4kx1) DRAM
or 4116 (16kx1) DRAM
and had jumper switches to adjust the RAM size. The early Apple II+ models retained this feature, but after a drop in DRAM
prices, Apple redesigned the circuit boards without the jumpers so that only 16k chips were supported. A few months later they started shipping all machines with a full 48 KB complement of DRAM. Display and graphics[edit] Main article: Apple II
Apple II
graphics Color on the Apple II series
Apple II series
uses a quirk of the NTSC
television signal standard, which made color display relatively easy and inexpensive to implement. The original NTSC
television signal specification was black-and-white. Color was added on later by adding a 3.58- MHz
subcarrier signal that was partially ignored by black-and-white TV sets. Color is encoded based on the phase of this signal in relation to a reference color burst signal. The result is that the position, size, and intensity of a series of pulses define color information. These pulses can translate into pixels on the computer screen, with the possibility of exploiting composite artifact colors. The Apple II
Apple II
display provides two pixels per subcarrier cycle. When the color burst reference signal is turned on and the computer attached to a color display, it can display green by showing one alternating pattern of pixels, magenta with an opposite pattern of alternating pixels, and white by placing two pixels next to each other. Blue and orange are available by tweaking the offset of the pixels by half a pixel-width in relation to the color-burst signal. The high-resolution display offers more colors by compressing more (and narrower) pixels into each subcarrier cycle. The coarse, low-resolution graphics display mode works differently, as it can output a pattern of dots per pixel to offer more color options. These patterns are stored in the character generator ROM and replace the text character bit patterns when the computer is switched to low-res graphics mode. The text mode and low-res graphics mode use the same memory region and the same circuitry is used for both. Sound[edit] Rather than a dedicated sound-synthesis chip, the Apple II
Apple II
has a toggle circuit that can only emit a click through a built-in speaker or a line out jack; all other sounds (including two-, three- and, eventually, four-voice music and playback of audio samples and speech synthesis) are generated entirely by software that clicked the speaker at just the right times. Similar techniques are used for cassette storage: the cassette output works the same as the speaker, and the input is a simple zero-crossing detector that serves as a relatively crude (1-bit) audio digitizer. Routines in the ROM encode and decode data in frequency-shift keying for the cassette. Languages[edit] Initially, the Apple II
Apple II
was shipped with Integer BASIC encoded in the motherboard ROM chips. Written by Wozniak, the interpreter enabled users to write software applications without needing to purchase additional development utilities. Written with game programmers and hobbyists in mind, the language only supported the encoding of numbers in 16-bit integer format. But limiting numerical values to whole numbers between -32768 and +32767 reduced the machine's attractiveness to business users. Jobs responded by licensing a floating-point version of BASIC from Microsoft which was initially available as a plug-in expansion card. Named Applesoft BASIC, this more versatile (but slower) variant was more popular with customers, so later models were shipped with it as standard. Models with Applesoft BASIC
Applesoft BASIC
in ROM and the optional "Language Card" installed could load Integer BASIC from disk if needed. As shipped, the machine incorporated a "monitor" program which supported functions such as displaying and altering the contents of the computer's RAM memory in hexadecimal format, either one byte at a time or in blocks of 256 bytes at once. This feature enabled hackers to write and debug machine code programs without needing further development software. A 6502 assembler was soon offered on disk, and later the UCSD
compiler and operating system for the Pascal language were made available. The Pascal system required a 16 KB RAM card to be installed in the language card position (expansion slot 0) in addition to the full 48 KB of motherboard memory. Third-party devices and applications[edit] Wozniak's open-architecture design and the Apple II's multiple expansion slots permit a wide variety of third-party devices, including peripheral cards such as serial controllers, display controllers, memory boards, hard disks, networking components, and realtime clocks. There are plug-in expansion cards – such as the Z-80 SoftCard – that permit the Apple to use the Z80 processor and run programs for the CP/M
operating system,[21] including the dBase II database and the WordStar
word processor. The Z80 card also allows the connection to a modem and thereby to any networks that the user might have access to. In the early days, these were scarce, but expanded significantly with the development of bulletin board systems. There is also a third-party 6809 card that allows OS-9 Level One to be run. Third-party sound cards greatly improve audio capabilities, allowing simple music synthesis and text-to-speech functions. Apple II accelerator cards double or quadruple the computer's speed. Reception[edit]

Advertisement for the Apple II
Apple II

Jesse Adams Stein wrote, "As the first company to release a 'consumer appliance' micro-computer, Apple Computer offers us a clear view of this shift from a machine to an appliance." But the company also had "to negotiate the attitudes of its potential buyers, bearing in mind social anxieties about the uptake of new technologies in multiple contexts. The office, the home and the 'office-in-the-home' were implicated in these changing spheres of gender stereotypes and technological development."[22] After seeing a crude, wire-wrapped prototype demonstrated by Wozniak and Steve Jobs
Steve Jobs
in November 1976,[12] Byte predicted in April 1977 that the Apple II
Apple II
"may be the first product to fully qualify as the 'appliance computer' ... a completed system which is purchased off the retail shelf, taken home, plugged in and used". The computer's color graphics capability especially impressed the magazine.[23] The magazine published a favorable review of the computer in March 1978, concluding, "For the user that wants color graphics, the Apple II
Apple II
is the only practical choice available in the 'appliance' computer class".[12] Personal Computer World
Personal Computer World
in August 1978 also cited the color capability as a strength, stating that "the prime reason that anyone buys an Apple II
Apple II
must surely be for the colour graphics". While mentioning the "oddity" of the artifact colors that produced output "that is not always what one wishes to do", it noted that "no-one has colour graphics like this at this sort of price". The magazine praised the sophisticated monitor software, user expandability, and comprehensive documentation, and concluded that "the Apple II
Apple II
is a very promising machine" which "would be even more of a temptation were its price slightly lower ... for the moment, colour is an Apple II".[24] Although it sold well from the launch, the initial market was to hobbyists, games players and computer enthusiasts. Sales expanded exponentially into the business and professional market when the spreadsheet program VisiCalc
was launched in mid-1979. VisiCalc
is credited as being the defining "killer app" in the microcomputer industry. During the first five years of operations, revenues doubled about every four months. Between September 1977 and September 1980, yearly sales grew from $775,000 to $118 million.[25] During this period the sole products of the company were the Apple II
Apple II
and its peripherals, accessories and software. In popular culture[edit] In 2017, the band 8 Bit Weapon
8 Bit Weapon
released the world's first 100% Apple II-based music album entitled Class Apples. The album features dance-oriented cover versions of classical music by Bach, Beethoven, and Mozart recorded directly from the Apple II
Apple II
motherboard.[26] See also[edit]

Computer science portal 1970s portal


^ "Musée Bolo". École Polytechnique Fédérale de Lausanne. Retrieved October 23, 2011.  ^ Steven Weyhrich (2010-07-10). "1969-1977". Apple II
Apple II
History. Retrieved 2016-10-02.  ^ a b Steven Weyhrich (May 16, 2003). "1990-1995". Apple II
Apple II
History. Retrieved May 25, 2010.  ^ Reimer, Jeremy (December 14, 2005). "Total share: 30 years of personal computer market share figures". Ars Technica. Retrieved May 25, 2010.  ^ Isaacson, Walter (2011). Steve Jobs. Simon & Schuster. p. ebook.  ^ Wozniak, Steve. "woz.org: Comment From e-mail: Why didn't the early Apple II's use Fans?". woz.org. Retrieved 2015-05-10.  ^ a b c Stein, Jesse Adams (2011). "Domesticity, Gender and the 1977 Apple II
Apple II
Personal Computer". Design and Culture. 3 (2).  ^ "Most Important Companies". Byte. September 1995. Archived from the original on 2008-06-18. Retrieved 2008-06-10.  ^ Rose, Frank (1989). West of Eden. Arrow Books. p. 3. ISBN 0-09-976200-5.  ^ "June 10, 1977 - Apple II
Apple II
Released Today". This Day in History. Mountain View, CA: Computer History Museum. Retrieved August 3, 2012.  June 10, 1977 was a Friday. ^ Weyhrich, Steven. "4-The Apple II, cont. - Product Introduction". Apple II
Apple II
History. Apple2History.org. Retrieved August 3, 2012. The first motherboard-only Apple II
Apple II
computers shipped on May 10, 1977, for those who wanted to add their own case, keyboard, and power supply (or wanted to update their Apple-1 'system' with the latest and greatest). A month later, on June 10, 1977, Apple began shipping full Apple II systems.  ^ a b c Helmers, Carl (March 1978). "An Apple to Byte". BYTE. p. 18. Retrieved October 17, 2013.  ^ Ahl, David H.; Rost, Randi J. (1983), "Blisters And Frustration: Joysticks, Paddles, Buttons and Game Port Extenders for Apple, Atari and VIC", Creative Computing Video & Arcade Games, 1 (1): 106ff.  ^ Forster, Winnie (2005). The encyclopedia of consoles, handhelds & home computers 1972 – 2005. GAMEPLAN. p. 19. ISBN 3-00-015359-4.  ^ 1977 Apple II
Apple II
price list A-VIDD Electronics Co., 1977 Long Beach, CA. ^ Steven Weyhrich (April 21, 2002). "4-The Apple II, cont". Apple II History. Archived from the original on September 25, 2006. Retrieved November 16, 2006.  ^ Wozniak, Steve (May 1977). "System Description / The Apple-II". BYTE. pp. 34–43. Retrieved October 17, 2013.  ^ Gibson, Steve. "The origins of sub-pixel font rendering". Gibson Research Corporation. Archived from the original on July 21, 2006. Retrieved August 4, 2006.  ^ Steven Weyhrich (December 28, 2001). "5-The Disk II". Apple II History. Archived from the original on December 1, 2006. Retrieved November 16, 2006.  ^ Freiberger, Paul; Swaine, Michael (January 1985). Fire In The Valley, Part Two. A+ Magazine (Book excerpt). p. 45.  ^ Petersen, Marty (February 6, 1984). "Review: Premium Softcard IIe". InfoWorld. InfoWorld
Media Group (Vol. 6, Num. 6): 64. Several manufacturers, however, make Z80 coprocessor boards that plug into the Apple II.  ^ Stein, Jesse Adams, "In Memoriam: Domesticity, Gender and the 1977 Apple II
Apple II
Personal Computer," Design and Culture 3:2 (2011), 194. ^ Helmers, Carl (April 1977). "A Nybble on the Apple". BYTE. p. 10. Retrieved October 16, 2013.  ^ Coll, John; Sweeten, Charles (August 1978). "Colour is an Apple II". Personal Computer World. p. 50. Retrieved 18 August 2014.  ^ Infinite Loop, Malone, p157 ^ "Historic Apple II
Apple II
Album Released!". 8 Bit Weapon. 2017-07-22. Retrieved 2017-12-12. 

External links[edit]

Wikimedia Commons has media related to Apple II.

Additional documentation in Bitsavers PDF Document archive Apple II
Apple II
on Old-computers.com Online Apple II
Apple II

v t e

Apple hardware before 1998



Apple I Apple II
Apple II

II II Plus IIe IIc IIc Plus IIGS

Apple III

Compact Macintosh

128K 512K 512Ke Plus SE SE/30 Classic Classic II Color Classic

Macintosh II

II IIx IIcx IIci IIfx IIsi IIvi IIvx

Macintosh LC

LC LC II LC III LC 475 LC 500 series LC 630 5200 LC Macintosh TV

Macintosh Quadra

700 900 950 800 840AV 600 series

610 650 660AV 605 630


Macintosh Portable 68k-based PowerBooks

100 series

100 140 170 160 180 150 190

200 series

210 230

500 series

PowerPC-based PowerBooks

2300c 5300 1400 3400c 2400c

Power Macintosh

4400 and 7220 5000 series

5200 LC and 5300 LC 5260 5400 5500

6000 series

6100 6200 and 6300 6400 6500

7000 series

7100 7200 and 8200 7300 7500 7600

8000 series

8100 8500 8600

9000 series

9500 9600

Power Macintosh
Power Macintosh


Apple Lisa Macintosh XL Macintosh Performa Macintosh Centris Apple IIe
Apple IIe
Card (Macintosh PDS) Apple Workgroup Server


Apple Network Server Twentieth Anniversary Macintosh



Monitor III Monitor II AppleColor Composite IIe AppleColor High-Resolution RGB Macintosh Color AudioVision 14 Multiple Scan 14 ColorSync 750

External drives

Disk II Macintosh ProFile Hard Disk 20 Hard Disk 20SC AppleCD PowerCD Tape Drive 40SC

Input devices

Keyboard Desktop Bus Extended Keyboard Adjustable Keyboard Mouse Scanner QuickTake


Apple II
Apple II
serial cards Apple Modem LocalTalk Apple Communication Slot GeoPort


Silentype Dot Matrix Printer Letter Quality Printer ImageWriter LaserWriter 410 Color Plotter Color LaserWriter StyleWriter


MessagePad eMate 300


Paladin Interactive Television Box Pippin

Apple hardware since 1998

v t e

Steve Wozniak

Products and projects

Apple I Apple II Apple Desktop Bus Breakout Children's Discovery Museum of San Jose CL 9
CL 9
CORE Electronic Frontier Foundation iWoz US Festival


Acquicor Technology (co-founder) Apple, Inc.
Apple, Inc.
(co-founder) CL 9
CL 9
(founder) Fusion-io, Inc.
Fusion-io, Inc.
(chief scientist) Wheels of Zeus
Wheels of Zeus


Honors and awards for Steve Wozniak


Jobs Pirates of Silicon Valley Steve Jobs Triumph of the Nerds

TV appearances

"The Cruciferous Vegetable Amplification" (The Big Bang Theory) Dancing with the Stars season 8 Kathy Griffin: My Life on the D-List season 4


Apple IIGS
Apple IIGS
with limited edition signed case Blue box Hackers: Heroes of the Computer Revolution Homebrew Computer Club Steve Jobs Phreaking Segway polo His