View source for Engineering:Xerox Alto

{{Short description|Computer made by Xerox}}
{{Infobox computing device
| name = Xerox Alto
| image = Xerox Alto mit Rechner.JPG
| caption = The Alto has a keyboard, mouse, and [[Page orientation|portrait-oriented]] monitor.
| developer = Xerox PARC
| manufacturer = Xerox PARC
| type = 
| release date = {{Start date and age|1973|03|01}}
| connectivity = [[Ethernet]]
| lifespan = 
| price = {{US$|32,000|1979|round=-3}}<ref name="wadlow198109" />
| units shipped = Alto I: 120<br>Alto II: 2,000<ref>{{cite web|url=http://www.digibarn.com/collections/audio/digibarn-radio/ron-cude-xerox/ron-cude-xerox-fumbling-future-and-elixir.mp3|title=MP3 Audio of Ron Cude talking about the 1979 Boca Raton Alto Event|website=The DigiBarn Computer Museum|date=2003|archive-url=https://web.archive.org/web/20200918031608/http://www.digibarn.com/collections/audio/digibarn-radio/ron-cude-xerox/ron-cude-xerox-fumbling-future-and-elixir.mp3|archive-date=September 18, 2020|url-status=live}}</ref>
| media = 2.5 [[Megabyte|MB]] one-platter [[Engineering:Disk pack#Disk cartridge|disk cartridge]]<ref name=alto/>
| os = Alto Executive (Exec)
| input = [[Computer keyboard|Keyboard]], 3-button mouse, 5-key chorded keyboard
| power = 
| cpu = [[Transistor–transistor logic|TTL]]-based, with the [[Arithmetic logic unit|ALU]] built around four [[Engineering:74181|74181]] MSI chips. It has user programmable [[Microcode|microcode]], uses big-endian format and a CPU clock of {{nowrap|5.88 MHz}}.<ref>{{cite web|title=Alto I Schematics|url=http://bitsavers.org/pdf/xerox/alto/schematics/AltoI_Schematics.pdf|website=Bitsavers|access-date=July 21, 2016|page=54|archive-date=February 24, 2021|archive-url=https://web.archive.org/web/20210224014316/http://bitsavers.org/pdf/xerox/alto/schematics/AltoI_Schematics.pdf|url-status=live}}</ref><ref name=alto>{{cite web
|title=History of Computers and Computing, Birth of the modern computer, Personal computer, Xerox Alto
|access-date=April 19, 2016
|url=http://history-computer.com/ModernComputer/Personal/Alto.html
|archive-date=December 5, 2020
|archive-url=https://web.archive.org/web/20201205082025/https://history-computer.com/ModernComputer/Personal/Alto.html
|url-status=live
}}</ref>
| storage = 
| memory = 96<ref name="manual">{{cite book|title=Alto Operating System Reference Manual|date=June 26, 1975|publisher=Xerox PARC|page=2|url=http://bitsavers.org/pdf/xerox/alto/memos_1975/Alto_Operating_System_Reference_Manual_Jun75.pdf|access-date=July 21, 2016|archive-date=July 17, 2019|archive-url=https://web.archive.org/web/20190717004756/http://bitsavers.org/pdf/xerox/alto/memos_1975/Alto_Operating_System_Reference_Manual_Jun75.pdf|url-status=live}}</ref> – 512 [[Kilobyte|KB]] (128 KB for $4000)<ref name=alto/>
| display = 606 × 808 pixels<ref name=alto/>
| audio = 
| service = <!-- online service/s offered -->
| dimensions = 
| weight = 
| successor = [[Engineering:Xerox Star|Xerox Star]]
| related = [[Software:Lilith (computer)|ETH Lilith]]; {{br}}[[Engineering:Apple Lisa|Lisa]]; {{br}}Apollo/Domain
}}

The '''Xerox Alto''' is a computer system developed at [[Company:PARC|Xerox PARC]] (Palo Alto Research Center) in the 1970s. It is variously considered one of the first [[Workstation|workstation]]s or [[Engineering:Personal computer|personal computer]]s, and its development pioneered many aspects of modern computing. It features a [[Graphical user interface|graphical user interface]] (GUI), a [[Computer mouse|mouse]], [[Ethernet]] networking, and the ability to run multiple applications simultaneously. It is one of the first computers to use a [[WYSIWYG]] (What You See Is What You Get) text editor and has a bit-mapped display. The Alto did not succeed commercially, but it had a significant influence on the development of future computer systems.

The Alto was designed for an [[Operating system|operating system]] based on a GUI, later using the [[Desktop metaphor|desktop metaphor]].<ref name="Koved Selker 1999">{{cite web |last1=Koved |first1=Larry |first2=Ted |last2=Selker |title=Room with a view (RWAV): A metaphor for interactive computing. |url=https://citeseerx.ist.psu.edu/doc/10.1.1.22.1340 |citeseerx=10.1.1.22.1340 |publisher=IBM TJ Watson Research Center |date=1999 |format=[[File:Icon pdf file.png]] PDF}}</ref><ref>{{cite book |last1=Thacker |first1=Charles P. |first2=Ed |last2=McCreight |author-link2=Edward M. McCreight |first3=Butler |last3=Lampson |author-link3=Butler Lampson |first4=Robert |last4=Sproull |author-link4=Bob Sproull |first5=David |last5=Boggs |author-link5=Dave Boggs |chapter-url=https://archive.org/details/computerstructures00siew/page/549/mode/1up <!-- http://research.microsoft.com/en-us/um/people/blampson/25-Alto/25-Alto.pdf --> |chapter=Alto: A personal computer |title=Computer Structures: Principles and Examples |edition=2nd |date=September 1981 |pages=549-572 |editor-first1=Daniel P. |editor-last1=Siewiorek |editor-first2=C. Gordon |editor-last2=Bell |editor-link2=Gordon Bell |editor-first3=Allen |editor-last3=Newell |editor-link3=Allen Newell |publisher=McGraw-Hill |isbn=978-0-07-057302-4}}</ref> The first machines were introduced on March 1, 1973,<ref>{{cite web |url=http://toastytech.com/guis/alto.html |title=The Xerox Alto |website=Nathan's Toasty Technology page |access-date=April 28, 2021 |archive-date=July 4, 2021 |archive-url=https://web.archive.org/web/20210704032636/http://toastytech.com/guis/alto.html |url-status=live }}</ref> and in limited production starting one decade before Xerox's designs inspired Apple to release the first mass-market GUI computers. The Alto is contained in a relatively small cabinet and uses a custom [[Central processing unit|central processing unit]] (CPU) built from multiple SSI and MSI [[Engineering:Integrated circuit|integrated circuit]]s. Each machine cost tens of thousands of dollars. Few were built initially, but by the late 1970s, about 1,000 were in use at various Xerox laboratories, and about another 500 in several universities. Total production was about 2,000 systems.

The Alto became well known in Silicon Valley and its GUI was increasingly seen as the future of computing. In 1979, [[Biography:Steve Jobs|Steve Jobs]] arranged a visit to Xerox PARC, during which [[Company:Apple Inc.|Apple Computer]] personnel received demonstrations of Xerox technology in exchange for Xerox being able to purchase stock [[Finance:Option|options]] in Apple.<ref>{{Cite web|url=https://web.stanford.edu/dept/SUL/sites/mac/parc.html|title=The Xerox PARC Visit|website=web.stanford.edu|access-date=September 2, 2018|archive-date=September 24, 2021|archive-url=https://web.archive.org/web/20210924110717/https://web.stanford.edu/dept/SUL/sites/mac/parc.html|url-status=live}}</ref> After two visits to see the Alto, Apple engineers used the concepts in developing the [[Engineering:Apple Lisa|Lisa]] and Macintosh systems.

In 1981, Xerox commercialized a line of office computers, the [[Engineering:Xerox Star|Star]], based on concepts from the Alto. A complete office system including several workstations, storage, and a [[Engineering:Laser printing|laser printer]] cost up to {{US$|100,000|1981|long=no|round=-3}}. Like the Alto, the Star had little direct impact on the market.

==History==
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[[File:Xerox Alto keyset.jpg|upright|thumb|The Alto keyset is a chorded keyboard that never became popular.]]
The Alto is the first computer with a graphical operating system, and was built on earlier graphical interface designs. It was conceived in 1972 in a memo written by [[Biography:Butler Lampson|Butler Lampson]], inspired by the [[Engineering:NLS (computer system)|oN-Line System]] (NLS) developed by [[Biography:Douglas Engelbart|Douglas Engelbart]] and Dustin Lindberg at [[Organization:SRI International|SRI International]] (SRI). Of further influence was the PLATO education system developed at the Computer-based Education Research Laboratory at the University of Illinois.<ref>{{cite book|last=Dear|first=Brian|title=The Friendly Orange Glow: The untold story of the PLATO System and the dawn of cyberculture|date=2017|publisher=Pantheon Books|isbn=978-1-101-87155-3|pages=186–187}}</ref> The Alto was designed mostly by [[Biography:Charles P. Thacker|Charles P. Thacker]]. Industrial Design and manufacturing was sub-contracted to [[Company:Xerox|Xerox]], whose Special Programs Group team included Doug Stewart as Program Manager, Abbey Silverstone Operations Manager, Bob Nishimura, Industrial Designer. An initial run of 30 units was produced by Xerox El Segundo (Special Programs Group), working with John Ellenby at PARC and Doug Stewart and Abbey Silverstone at El Segundo, who were responsible for re-designing the Alto's electronics. Due to the success of the pilot run, the team went on to produce approximately 2,000 units over the next ten years.<ref name=clement>"The History of the Xerox Alto". Carl J. Clement. March 2002.</ref>

Several Xerox Alto chassis are now on display at the Computer History Museum in Mountain View, California, one is on display at the Computer Museum of America in Roswell, Georgia, and several are in private hands. Running systems are on display at the System Source Computer Museum in Hunt Valley, Maryland. Charles P. Thacker was awarded the 2009 Turing Award of the [[Organization:Association for Computing Machinery|Association for Computing Machinery]] on March 9, 2010, for his pioneering design and realization of the Alto.<ref>{{cite web |title=ACM Turing Award Goes to Creator of First Modern Personal Computer |url=http://www.acm.org/press-room/news-releases/2010/turing-award-09 |last=Gold |first=Virginia |date=2010 |publisher=Association for Computing Machinery |access-date=January 11, 2011 |archive-date=March 11, 2010 |archive-url=https://web.archive.org/web/20100311223801/http://www.acm.org/press-room/news-releases/2010/turing-award-09 |url-status=live }}</ref> The 2004 Charles Stark Draper Prize was awarded to Thacker, [[Biography:Alan Kay|Alan C. Kay]], Butler Lampson, and [[Biography:Robert Taylor (computer scientist)|Robert W. Taylor]] for their work on Alto.<ref>{{Cite web |url=http://www.nae.edu/Activities/Projects20676/Awards/20681/PastWinners/page20048879.aspx |title="2004 Recipients of the Charles Stark Draper Prize" |access-date=November 15, 2011 |archive-date=November 5, 2010 |archive-url=https://web.archive.org/web/20101105150119/http://www.nae.edu/Activities/Projects20676/Awards/20681/PastWinners/page20048879.aspx |url-status=live }}</ref>

On October 21, 2014, Xerox Alto's [[Source code|source code]] and other resources were released from the Computer History Museum.<ref>{{cite web |url=http://www.computerhistory.org/atchm/xerox-alto-source-code/ |quote=''With the permission of the Palo Alto Research Center, the Computer History Museum is pleased to make available, for non-commercial use only, snapshots of Alto source code, executables, documentation, font files, and other files from 1975 to 1987.'' |title=Xerox Alto Source Code - The roots of the modern personal computer |publisher=Computer History Museum |first=Paul |last=McJones |work=Software Gems: The Computer History Museum Historical Source Code Series |date=October 21, 2014 |access-date=January 8, 2015 |archive-date=January 2, 2015 |archive-url=https://web.archive.org/web/20150102201034/http://www.computerhistory.org/atchm/xerox-alto-source-code/ |url-status=live }}</ref>

==Architecture==
The following description is based mostly on the August 1976 Alto Hardware Manual by Xerox PARC.<ref name="AltoHardwareManual">{{cite web |title=Alto Hardware Manual |url=http://bitsavers.org/pdf/xerox/alto/Alto_Hardware_Manual_Aug76.pdf |website=bitsavers.org |publisher=Xerox |access-date=July 17, 2019 |archive-date=September 4, 2017 |archive-url=https://web.archive.org/web/20170904111228/http://bitsavers.org/pdf/xerox/alto/Alto_Hardware_Manual_Aug76.pdf |url-status=live }}</ref>

Alto uses a microcoded design, but unlike many computers, the [[Microcode|microcode]] engine is not hidden from the programmer in a layered design. Applications such as Pinball take advantage of this to accelerate performance. The Alto has a [[Bit slicing|bit-slice]] [[Arithmetic logic unit|arithmetic logic unit]] (ALU) based on the [[Company:Texas Instruments|Texas Instruments]] [[Engineering:74181|74181]] chip, a ROM control store with a writable control store extension and has 128 (expandable to 512) [[Kilobyte|KB]] of [[Computer data storage#Primary storage|main memory]] organized in 16-bit words. Mass storage is provided by a [[Engineering:Hard disk drive|hard disk drive]] that uses a removable 2.5 [[Megabyte|MB]] one-platter cartridge (Diablo Systems, a company Xerox later bought) similar to those used by the [[Engineering:IBM 2310|IBM 2310]]. The base machine and one disk drive are housed in a cabinet about the size of a small [[Physics:Refrigerator|refrigerator]]; one more disk drive can be added via [[Daisy chain (electrical engineering)|daisy-chaining]].

Alto both blurs and ignores the distinction between functional elements. Rather than a distinct [[Central processing unit|central processing unit]] with a well-defined electrical interface (such as a [[Engineering:System bus|system bus]]) to storage and peripherals, the Alto ALU interacts directly with hardware interfaces to memory and peripherals, driven by microinstructions that are output from the control store. The microcode machine supports up to 16 [[Cooperative multitasking|cooperative multitasking]] tasks, each with [[Scheduling (computing)|fixed priority]]. The emulator task executes the normal instruction set to which most applications are written; that instruction set is similar to a [[Engineering:Data General Nova|Data General Nova]].<ref>{{cite report |last1=Thacker |first1=Charles P. |last2=McCreight |first2=Edward M. |date=December 1974 |url=http://www.bitsavers.org/pdf/xerox/alto/memos_1974/Alto_A_Personal_Computer_Dec74.pdf |title=Alto: A Personal Computer System |page=13 |access-date=December 11, 2019 |archive-date=August 14, 2011 |archive-url=https://web.archive.org/web/20110814232255/http://www.bitsavers.org/pdf/xerox/alto/memos_1974/Alto_A_Personal_Computer_Dec74.pdf |url-status=live }}</ref> Other tasks serve the display, memory refresh, disk, network, and other I/O functions. For example, the bitmap display controller is little more than a 16-[[Bit|bit]] [[Shift register|shift register]]; microcode moves display refresh data from main memory to the shift register, which serializes it into a display of pixels corresponding to the ones and zeros of the memory data. Ethernet is likewise supported by minimal hardware, with a shift register that acts bidirectionally to serialize output words and deserialize input words. Its speed was designed to be 3 Mbit/s because the microcode engine can not go faster and continue to support the video display, disk activity, and memory refresh.

Unlike most [[Minicomputer|minicomputer]]s of the era, Alto does not support a [[Computer terminal|serial terminal]] for user interface. Apart from an [[Ethernet]] connection, the Alto's only common output device is a bi-level (black and white) [[Engineering:Cathode-ray tube|cathode-ray tube]] (CRT) [[Engineering:Computer monitor|display]] with a tilt-and-swivel base, mounted in [[Page orientation|portrait orientation]] rather than the more common "landscape" orientation. Its input devices are a custom detachable [[Computer keyboard|keyboard]], a three-button [[Computer mouse|mouse]], and an optional 5-key chorded keyboard (chord keyset). The last two items had been introduced by SRI's On-Line System and the mouse was an instant success among Alto users, but the chord keyset never became popular.

In the early mice, the buttons are three narrow bars, arranged top to bottom rather than side to side; they were named after their colors in the documentation. The motion is sensed by two perpendicular wheels. These were soon replaced with a ball-type mouse, which was invented by Ronald E. Rider and developed by [[Biography:Bill English (computer engineer)|Bill English]]. These are photo-mechanical mice, first using white light, and then [[Physics:Infrared|infrared]] (IR), to count the rotations of wheels inside the mouse.

Each key on the Alto keyboard is represented as a separate bit in a set of memory locations. As a result, it is possible to read multiple key presses concurrently. This trait can be used to alter from where on the disk the Alto boots. The keyboard value is used as the sector address on the disk to boot from, and by holding specific keys down while pressing the boot button, different microcode and operating systems can be loaded. This gave rise to the expression "nose boot" where the keys needed to boot for a test OS release requires more fingers than the user can articulate. Nose boots were obsoleted by the <code>move2keys</code> program that shifts files on the disk so that a specified key sequence can be used.

Several other I/O devices were developed for the Alto, including a television camera, the Hy-Type daisywheel printer and a parallel port, although these were quite rare. The Alto could also control external disk drives to act as a [[File server|file server]]. This was a common application for the machine.

==Software==
[[File:Alto Neptune Filemanager.gif|thumb|Neptune is the Alto's file manager program.]]
Early software for the Alto was written in the [[Programming language|programming language]] [[BCPL]], and later in [[Mesa (programming language)|Mesa]],{{r|wadlow198109}} which was not widely used outside PARC but influenced several later languages, such as [[Modula]]. The Alto used an early version of [[ASCII]] which lacked the underscore character, instead having the left-arrow character used in [[ALGOL 60]] and many derivatives for the [[Assignment operator|assignment operator]]: this peculiarity may have been the source of the CamelCase style for compound [[Identifier|identifier]]s. Altos were also microcode-programmable by users.<ref name="AltoHardwareManual"/>

The Alto helped popularize the use of [[Raster graphics|raster graphics]] model for all output, including text and graphics. It also introduced the concept of the ''bit block transfer'' operation ([[Bit blit|bit blit]], BitBLT), as the fundamental programming interface to the display. Despite its small memory size, many innovative programs were written for the Alto, including:
* the first [[WYSIWYG]] typesetting document preparation systems, [[Software:Bravo|Bravo]] and [[Software:Gypsy|Gypsy]];
* the Laurel [[Email|email]] tool,<ref>{{cite web |url=http://xeroxalto.computerhistory.org/Indigo/DMS/Laurel/6/Manual/.Laurel6.press!1.pdf |title=Laurel Manual |last=Brotz |first=Douglas K. |date=May 1981 |publisher=Xerox |access-date=August 23, 2019 |archive-date=August 23, 2019 |archive-url=https://web.archive.org/web/20190823031609/http://xeroxalto.computerhistory.org/Indigo/DMS/Laurel/6/Manual/.Laurel6.press!1.pdf |url-status=live }}</ref> and its successor, Hardy<ref>{{cite news |last=Ollig |first=Mark |date=October 31, 2011 |url=http://www.herald-journal.com/archives/2011/columns/mo103111.html |title=They could have owned the computer industry |work=Herald Journal |access-date=February 26, 2021 |archive-date=February 27, 2021 |archive-url=https://web.archive.org/web/20210227062954/http://www.herald-journal.com/archives/2011/columns/mo103111.html |url-status=live }}</ref><ref>{{cite web |url=https://www.thocp.net/hardware/xerox_star.htm |title=Xerox Star |website=The History of Computing Project |access-date=August 23, 2019 |archive-date=February 1, 2020 |archive-url=https://web.archive.org/web/20200201141152/http://www.thocp.net/hardware/xerox_star.htm |url-status=live }}</ref>
* the Sil vector graphics editor, used mainly for logic circuits, [[Engineering:Printed circuit board|printed circuit board]], and other technical diagrams;
* the Markup [[Bitmap|bitmap]] editor (an early [[Software:Raster graphics editor|paint program]]);
* the Draw graphical editor using lines and splines;
* the first WYSIWYG [[Engineering:IC layout editor|integrated circuit editor]] based on the work of [[Biography:Lynn Conway|Lynn Conway]], [[Biography:Carver Mead|Carver Mead]], and the Mead and Conway revolution;
* the first versions of the [[Smalltalk]] environment
* [[Interlisp]]
* one of the first network-based multi-person [[Engineering:Video game|video game]]s (''Alto Trek'' by Gene Ball).
There was no spreadsheet or database software. The first electronic spreadsheet program, [[Software:VisiCalc|VisiCalc]], did not appear until 1979.

==Diffusion and evolution==
Technically, the Alto is a small minicomputer, but it could be considered a [[Engineering:Personal computer|personal computer]] in the sense that it is used by one person sitting at a desk, in contrast with the [[Mainframe computer|mainframe computer]]s and other [[Minicomputer|minicomputer]]s of the era. It is arguably "the first personal computer", although this title is disputed. More significantly (and perhaps less controversially), it may be considered to be one of the first [[Workstation|workstation]] systems, with successors such as the Apollo workstations and systems by [[Company:Symbolics|Symbolics]] (designed to natively run [[Lisp (programming language)|Lisp]] as a development environment).<ref>{{cite web |title=Personal Computer Milestones |url=http://www.blinkenlights.com/pc.shtml |author=<!-- Unstated --> |date=<!-- Undated --> |publisher=Blinkenlights Archaeological Institute |access-date=December 31, 2006 |archive-date=August 2, 2021 |archive-url=https://web.archive.org/web/20210802180248/http://www.blinkenlights.com/pc.shtml |url-status=live }}</ref>

In 1976 to 1977, the Swiss computer pioneer [[Biography:Niklaus Wirth|Niklaus Wirth]] spent a sabbatical at PARC and was excited by the Alto. Unable to bring back an Alto system to Europe, Wirth decided to build a new system from scratch and he designed with his group the [[Software:Lilith (computer)|Lilith]].<ref>{{cite web|url=http://www.ethistory.ethz.ch/rueckblicke/departemente/dinfk/forschung/weitere_seiten/lilith/index_EN/popupfriendly/|title=Lilith Workstation|access-date=January 3, 2017|archive-date=March 3, 2017|archive-url=https://web.archive.org/web/20170303134438/http://www.ethistory.ethz.ch/rueckblicke/departemente/dinfk/forschung/weitere_seiten/lilith/index_EN/popupfriendly/|url-status=live}}</ref> It was ready to use around 1980, before Apple released [[Engineering:Apple Lisa|Lisa]] in 1981 and Macintosh in 1984. Around 1985, Wirth started a complete redesign of the Lilith under the Name [[Software:Oberon (operating system)|"Project Oberon"]].

In 1978, Xerox donated 50 Altos to the [[Organization:Massachusetts Institute of Technology|Massachusetts Institute of Technology]], [[Organization:Stanford University|Stanford University]], [[Organization:Carnegie Mellon University|Carnegie Mellon University]],<ref name="wadlow198109">{{cite magazine |last=Wadlow |first=Thomas A. |date=September 1981 |url=https://archive.org/stream/byte-magazine-1981-09/BYTE_Vol_06-09_1981-09_Artifical_Intelligence#page/n59/mode/2up |title=The Xerox Alto Computer |magazine=Byte |access-date=October 19, 2013 |pages=58 |volume=6 |issue=9}}</ref> and the [[Organization:University of Rochester|University of Rochester]].<ref name="denber198202">{{cite magazine |last=Denber |first=Michel |date=February 1982 |url=https://archive.org/stream/byte-magazine-1982-02/1982_02_BYTE_07-02_Winter_Computing#page/n29/mode/2up |title=Altos Gamesmen |magazine=Byte |access-date=October 19, 2013 |type=letter |pages=28 |volume=7 |issue=2}}</ref> The National Bureau of Standards's Institute for Computer Sciences in Gaithersburg, Maryland received one Alto in late 1978 along with Xerox Interim File System (IFS) file servers and Dover laser printers. These machines inspired the ETH Zuerich [[Software:Lilith (computer)|Lilith]] and Three Rivers Company [[Engineering:PERQ|PERQ]] workstations, and the Stanford University Network (SUN) workstation, which launched a spin-off company, [[Company:Sun Microsystems|Sun Microsystems]]. The Apollo/Domain workstation was heavily influenced by the Alto.

Following the acquisition of an Alto, the White House information systems department sought to lead federal computer suppliers in its direction. The Executive Office of the President of the United States (EOP) issued a [[Finance:Request for proposal|request for proposal]] for a computer system to replace the aging Office of Management and Budget (OMB) budget system, using Alto-like workstations, connected to an IBM-compatible mainframe. The request was eventually withdrawn because no mainframe producer could supply such a configuration.

In December 1979, [[Company:Apple Inc.|Apple Computer]]'s co-founder [[Biography:Steve Jobs|Steve Jobs]] visited Xerox PARC, where he was shown the [[Smalltalk]]-76 object-oriented programming environment, networking, and most importantly the [[WYSIWYG]], mouse-driven [[Graphical user interface|graphical user interface]] provided by the Alto. At the time, he didn't recognize the significance of the first two, but was excited by the last one. The GUI was promptly integrating into Apple's products, first into the [[Engineering:Apple Lisa|Lisa]] and then in the Macintosh, and Jobs recruited several key researchers from PARC.<ref name=nerds>{{cite web |title=PBS Triumph of the Nerds Television Program Transcripts: Part III |publisher=PBS (Public Broadcasting System) |url=https://www.pbs.org/nerds/part3.html |access-date=February 8, 2007 |archive-date=December 16, 2017 |archive-url=https://web.archive.org/web/20171216210647/http://www.pbs.org/nerds/part3.html |url-status=live }}</ref>

In 1980-1981, Altos were used by engineers at PARC and at the Xerox System Development Department to design the [[Engineering:Xerox Star|Star]] workstations.

==Xerox and the Alto==
Xerox was slow to realize the value of the technology that had been developed at PARC.<ref name=fumble>{{cite book |last1=Smith |first1=Douglas K. |last2=Alexander |first2=Robert C. |year=1988 |title=Fumbling the Future: How Xerox Invented, Then Ignored, the First Personal Computer |publisher=William Morrow |location=New York |isbn=978-0688069599 |url=https://archive.org/details/fumblingfutureho0000smit |url-access=registration}}</ref> The Xerox corporate acquisition of [[Company:Scientific Data Systems|Scientific Data Systems]] (SDS, later XDS) in the late 1960s had no interest to PARC. PARC built their own emulation of the Digital Equipment Corporation [[Engineering:PDP-10|PDP-10]] named the MAXC.<ref>{{cite magazine |last=Fiala |first=Edward R. |date=May 1978 |url=https://www.computer.org/csdl/magazine/co/1978/05/01646959/13rRUy3gmXN |title=The Maxc Systems |magazine=Computer |volume=11 |issue=5 |pages=57–67 |doi=10.1109/C-M.1978.218184 |s2cid=16813696 |access-date=April 29, 2021 |archive-date=April 29, 2021 |archive-url=https://web.archive.org/web/20210429050254/https://www.computer.org/csdl/magazine/co/1978/05/01646959/13rRUy3gmXN |url-status=live }}</ref> The MAXC was PARC's gateway machine to the [[Engineering:ARPANET|ARPANET]]. The firm was reluctant to get into the computer business again with commercially untested designs, although many of the philosophies would ship in later products.

''Byte'' magazine stated in 1981,{{r|wadlow198109}}

{{quote|It is unlikely that a person outside of the computer-science research community will ever be able to buy an Alto. They are not intended for commercial sale, but rather as development tools for Xerox, and so will not be mass-produced. What makes them worthy of mention is the fact that a large number of the personal computers of tomorrow will be designed with knowledge gained from the development of the Alto.}}

After the Alto, PARC developed more powerful workstations (none intended as projects{{clarify|date=June 2013}}) informally termed "the D-machines": Dandelion (least powerful, but the only to be made a product in one form), Dolphin; Dorado (most powerful; an [[Emitter-coupled logic|emitter-coupled logic]] (ECL) machine); and hybrids like the Dandel-Iris.

Before the advent of personal computers such as the Apple II in 1977 and the [[Engineering:IBM Personal Computer|IBM Personal Computer]] (IBM PC) in 1981, the computer market was dominated by costly mainframes and minicomputers equipped with dumb terminals that time-shared the processing time of the central computer. Through the 1970s, Xerox showed no interest in PARC's work. When Xerox finally entered the PC market with the [[Engineering:Xerox 820|Xerox 820]], it pointedly rejected the Alto design and opted instead for a very conventional model, a CP/M-based machine with the then-standard 80 by 24 character-only monitor and no mouse.

With the help of PARC researchers, Xerox eventually developed the [[Engineering:Xerox Star|Star]], based on the Dandelion workstation, and later the cost-reduced Star, the 6085 office system, based on the [[Engineering:Xerox Daybreak|Daybreak]] workstation. These machines, based on the Wildflower architecture described in a paper by [[Biography:Butler Lampson|Butler Lampson]], incorporated most of the Alto innovations, including the [[Graphical user interface|graphical user interface]] with icons, windows, folders, Ethernet-based local networking, and network-based laser printer services.

Xerox only realized its mistake in the early 1980s, after the Macintosh revolutionized the PC market via its bitmap display and the mouse-centered interface. Both of these were inspired by the Alto.<ref name=fumble/> The Xerox Star series was a relative commercial success, but it came too late. The expensive Xerox workstations could not compete against the cheaper GUI-based workstations that arose in the wake of the first Macintosh, and Xerox eventually quit the workstation market.

==See also==
*[[Engineering:NLS (computer system)|NLS (computer system)]]
*[[Mousepad]]
*[[Biography:Alan Kay|Alan Kay]]
*[[Biography:Adele Goldberg (computer scientist)|Adele Goldberg (computer scientist)]]
{{s-start}}
{{s-ttl|title  = Xerox Alto |years = 1973–1975 (Alto I)<ref name="Tomitsch 2003">{{Cite web|last=Tomitsch|first=Martin|title=Trends and Evolution of Window Interfaces|date=January 2003|url=https://www.researchgate.net/profile/Martin-Tomitsch/publication/248159192_Trends_and_evolution_of_window_interfaces/links/5438556e0cf204cab1d6d3a1/Trends-and-evolution-of-window-interfaces.pdf|access-date=March 3, 2023}}</ref>
{{br}} 1975–1981 (Alto II)}}
{{s-aft|after  = [[Engineering:Xerox Star|Xerox Star]] }}
{{end}}

==References==
{{Reflist}}

==Further reading==
* {{cite book |title=Alto user's handbook : September 1979 |publisher=Xerox Palo Alto Research Center |publication-place=Palo Alto, Calif. |date=September 1979 |oclc=7271372 |url=http://bitsavers.org/pdf/xerox/alto/Alto_Users_Handbook_Sep79.pdf}}
*{{cite book |last=Hiltzik |first=Michael A. |year=1999 |title=Dealers of Lightning: Xerox PARC and the Dawn of the Computer Age |publisher=HarperCollins |location=New York |isbn=978-0887309892 |url=https://archive.org/details/dealersoflightni00hilt |url-access=registration}}
* {{cite web |last=Brock |first=David C. |title=50 Years Later, We’re Still Living in the Xerox Alto’s World |website=IEEE Spectrum |date=March 1, 2023 |url=https://spectrum.ieee.org/xerox-alto |access-date=March 3, 2023 |ref=none}}

==External links==
*[http://www.bitsavers.org/pdf/xerox/alto/ Xerox Alto documents at bitsavers.org]
*[http://www.digibarn.com/collections/systems/xerox-alto/ At the DigiBarn museum]
*[https://computerhistory.org/blog/xerox-alto-source-code/?key=xerox-alto-source-code Xerox Alto Source Code - CHM (computerhistory.org)]
*[http://xeroxalto.computerhistory.org/xerox_alto_file_system_archive.html Xerox Alto source code (computerhistory.org)]
*[https://www.righto.com/2016/06/hello-world-in-bcpl-language-on-xerox.html "Hello world" in the BCPL language on the Xerox Alto simulator (righto.com)]
*[http://www.maniacworld.com/alto-computer-video.html The Alto in 1974] video
*[http://norfolk.cs.washington.edu/htbin-post/unrestricted/colloq/details.cgi?id=560 A lecture video of Butler Lampson describing Xerox Alto in depth. (length: 2h45m)]
*[http://altogether.brouhaha.com A microcode-level Xerox Alto simulator]
*[https://www.livingcomputers.org/Computer-Collection/Vintage-Computers/Emulations/ContrAlto.aspx ContrAlto Xerox Alto emulator]
*[https://github.com/brainsqueezer/salto_simulator brainsqueezer/salto_simulator: SALTO - Xerox Alto I/II Simulator (github.com)]
*[http://toastytech.com/guis/salto.zip SALTO-Xerox Alto emulator] (direct download)
*[https://archives.loomcom.com/contraltojs/ ConrAltoJS Xerox Alto Online]


[[Category:16-bit computers]]
[[Category:Computer workstations]]
[[Category:Personal computers]]

{{Sourceattribution|Xerox Alto}}