View source for Engineering:ENIAC

{{Short description|First electronic general-purpose digital computer}}
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{{Infobox PAhistoric
| name                 = ENIAC
| PAhistoric_type      = PA
| image                = ENIAC Penn1.jpg
| caption              = Four ENIAC panels and one of its three function tables at the School of Engineering and Applied Science at the [[Organization:University of Pennsylvania|University of Pennsylvania]]
| coordinates          = {{coord|39.9523|N|75.1906|W|region:US-PA_type:landmark|display=inline,title}}
| location             = [[Organization:University of Pennsylvania|University of Pennsylvania]] Department of Computer and Information Science, 3330 Walnut Street, Philadelphia, Pennsylvania, U.S.
| built                = 1945
| architect            =
| architecture         =
| governing_body       =
| designated_PAhistoric_type = Thursday, June 15, 2000
}}
[[File:Glen Beck and Betty Snyder program the ENIAC in building 328 at the Ballistic Research Laboratory.jpg|thumb|Glenn A. Beck (background) and Betty Snyder (foreground) program ENIAC in BRL building 328. (U.S. Army photo, c. 1947–1955)]]
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       Official sources (eg, the US patent) have 'And' for the 'A'.
                   Not 'Analyzer' or 'Automatic'.
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'''ENIAC''' ({{IPAc-en|'|ɛ|n|i|æ|k|}}; '''Electronic Numerical Integrator and Computer''')<ref>Eckert Jr., John Presper and Mauchly, John W.; Electronic Numerical Integrator and Computer, United States Patent Office, US Patent 3,120,606, filed 1947-06-26, issued 1964-02-04; invalidated 1973-10-19 after court ruling in ''Honeywell v. Sperry Rand''.</ref><ref name="ENIACstory">{{cite journal |last=Weik |first=Martin H. |title=The ENIAC Story |journal=Ordnance |issue=January–February 1961 |publisher=American Ordnance Association |url=http://ftp.arl.mil/~mike/comphist/eniac-story.html |access-date=2015-03-29 |url-status=dead |archive-url=https://web.archive.org/web/20110814181522/http://ftp.arl.mil/~mike/comphist/eniac-story.html |archive-date=2011-08-14 |location=Washington, DC}}</ref> was the first [[Computer programming|programmable]], [[Engineering:Electronics|electronic]], general-purpose digital computer, completed in 1945.<ref>{{cite web |url=https://www.phy.ornl.gov/csep/ov/node10.html |title=3.2 First Generation Electronic Computers (1937-1953) |website=www.phy.ornl.gov}}</ref><ref name=":0">{{cite web |url=http://www.ushistory.org/more/eniac/public.htm |title=ENIAC on Trial – 1. Public Use |website=www.ushistory.org |at=Search for ''1945'' |access-date=2018-05-16 |quote=The ENIAC machine [...] was reduced to practice no later than the date of commencement of the use of the machine for the Los Alamos calculations, December 10, 1945.}}</ref> There were other computers that had combinations of these features, but the ENIAC had all of them in one computer. It was Turing-complete and able to solve "a large class of numerical problems" through reprogramming.<ref>{{Harvnb|Goldstine|Goldstine|1946|p=97}}</ref><ref>{{cite book |last=Shurkin |first=Joel |title=Engines of the mind: the evolution of the computer from mainframes to microprocessors |date=1996 |publisher=Norton |location=New York |isbn=978-0-393-31471-7}}</ref>

ENIAC was designed by [[Biography:John Mauchly|John Mauchly]] and [[Biography:J. Presper Eckert|J. Presper Eckert]] to calculate [[Engineering:Artillery|artillery]] [[Physics:External ballistics|firing tables]] for the United States Army's Ballistic Research Laboratory (which later became a part of the Army Research Laboratory).<ref>{{cite web |last=Moye |first=William T. |title=ENIAC: The Army-Sponsored Revolution |date=January 1996 |publisher=US Army Research Laboratory |url=http://ftp.arl.mil/~mike/comphist/96summary/index.html |access-date=2015-03-29 |archive-url=https://web.archive.org/web/20170521072638/http://ftp.arl.mil/~mike/comphist/96summary/index.html |archive-date=2017-05-21 |url-status=dead}}</ref>{{sfn|Goldstine|1993|page=214}} However, its first program was a study of the feasibility of the [[Engineering:Thermonuclear weapon|thermonuclear weapon]].<ref>{{cite book |year=1995 |author=Richard Rhodes |title=Dark Sun: The Making of the Hydrogen Bomb |chapter=chapter 13 |pages=251 |quote=The first problem assigned to the first working electronic digital computer in the world was the hydrogen bomb. […] The ENIAC ran a first rough version of the thermonuclear calculations for six weeks in December 1945 and January 1946.}}</ref><ref>{{harvnb|McCartney|1999|p=103}}: "ENIAC correctly showed that Teller's scheme would not work, but the results led Teller and Ulam to come up with another design together."</ref>

ENIAC was completed in 1945 and first put to work for practical purposes on December 10, 1945.<ref name="trial">*{{cite web |url=http://www.ushistory.org/more/eniac/public.htm |title=ENIAC on Trial – 1. Public Use |website=www.ushistory.org |at=Search for ''1945'' |access-date=2018-05-16 |quote=The ENIAC machine […] was reduced to practice no later than the date of commencement of the use of the machine for the Los Alamos calculations, December 10, 1945.}}</ref>

ENIAC was formally dedicated at the [[Organization:University of Pennsylvania|University of Pennsylvania]] on February 15, 1946, having cost $487,000 ({{Inflation|US-GDP|487000|1943|fmt=eq|r=-5}}), and called a "Giant Brain" by the press.<ref>{{cite web |url= https://archive.nytimes.com/www.nytimes.com/library/books/061499mccartney-book-review.html|work={{wipe|The New York Times}}|title='ENIAC': Creating a Giant Brain, and Not Getting Credit}}</ref> It had a speed on the order of one thousand times faster than that of electro-mechanical machines.<ref>{{cite web |url=http://www.thocp.net/hardware/eniac.htm |title=ENIAC USA 1946 |date=2013-03-13 |website=The History of Computing Project |publisher=History of Computing Foundation |archive-url= https://web.archive.org/web/20210104011455/http://www.thocp.net/hardware/eniac.htm |archive-date=2021-01-04 |url-status=dead}}</ref>

ENIAC was formally accepted by the U.S. Army Ordnance Corps in July 1946. It was transferred to Aberdeen Proving Ground in Aberdeen, Maryland in 1947, where it was in continuous operation until 1955.

==Development and design==
ENIAC's design and construction was financed by the United States Army, Ordnance Corps, Research and Development Command, led by Major General Gladeon M. Barnes. The total cost was about $487,000, {{Inflation|US-GDP|487000|1943|fmt=eq|r=-5}}.<ref>{{cite web |url=http://history-computer.com/ModernComputer/Electronic/ENIAC.html |title=ENIAC |last=Dalakov |first=Georgi |website=History of Computers |publisher=Georgi Dalakov |access-date=2016-05-23}}</ref> The construction contract was signed on June 5, 1943; work on the computer began in secret at the [[Organization:University of Pennsylvania|University of Pennsylvania]]'s Moore School of Electrical Engineering<ref>{{Harvnb|Goldstine|Goldstine|1946}}</ref> the following month, under the code name "Project PX", with John Grist Brainerd as principal investigator. Herman H. Goldstine persuaded the Army to fund the project, which put him in charge to oversee it for them.<ref>{{cite web |author=Gayle Ronan Sims |date=June 22, 2004 |title=Herman Heine Goldstine |work=The Philadelphia Inquirer |url=http://www.princeton.edu/mudd/finding_aids/mathoral/pmcxgoldstine.htm |access-date=2017-04-15 |archive-url=https://web.archive.org/web/20151130170611/http://www.princeton.edu/mudd/finding_aids/mathoral/pmcxgoldstine.htm |archive-date=2015-11-30 |url-status=dead |via=www.princeton.edu}}</ref>

ENIAC was designed by [[Organization:Ursinus College|Ursinus College]] physics professor [[Biography:John Mauchly|John Mauchly]] and [[Biography:J. Presper Eckert|J. Presper Eckert]] of the University of Pennsylvania, U.S.<ref name="Wilkes">{{cite book |last=Wilkes |first=M. V. |title=Automatic Digital Computers |publisher={{wipe|John Wiley & Sons}} |date=1956 |location=New York |id=QA76.W5 1956}}</ref> The team of design engineers assisting the development included Robert F. Shaw (function tables), Jeffrey Chuan Chu (divider/square-rooter), Thomas Kite Sharpless (master programmer), Frank Mural (master programmer), [[Biography:Arthur Burks|Arthur Burks]] (multiplier), [[Biography:Harry Huskey|Harry Huskey]] (reader/printer) and Jack Davis (accumulators).<ref name="eniac-on-trial">{{cite web |title=ENIAC on Trial |url=https://www.ushistory.org/more/eniac/inventors.htm |website=USHistory.org |publisher=Independence Hall Association |access-date=9 November 2020 |archive-url=https://web.archive.org/web/20190812225517/https://www.ushistory.org/more/eniac/inventors.htm |archive-date=12 August 2019}}</ref> Significant development work was undertaken by the female mathematicians who handled the bulk of the ENIAC programming: [[Biography:Jean Bartik|Jean Jennings]], Marlyn Wescoff, Ruth Lichterman, Betty Snyder, Frances Bilas, and Kay McNulty.{{sfn|Light|1999}} In 1946, the researchers resigned from the University of Pennsylvania and formed the [[Company:Eckert–Mauchly Computer Corporation|Eckert–Mauchly Computer Corporation]].

ENIAC was a large, modular computer, composed of individual panels to perform different functions. Twenty of these modules were accumulators that could not only add and subtract, but hold a ten-digit [[Decimal|decimal]] number in memory. Numbers were passed between these units across several general-purpose [[Engineering:Bus (computing)|buses]] (or ''trays'', as they were called). In order to achieve its high speed, the panels had to send and receive numbers, compute, save the answer and trigger the next operation, all without any moving parts. Key to its versatility was the ability to ''branch''; it could trigger different operations, depending on the sign of a computed result.

===Components===
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By the end of its operation in 1956, ENIAC contained 18,000 [[Physics:Vacuum tube|vacuum tube]]s, 7,200 crystal diodes, 1,500 [[Engineering:Relay|relay]]s, 70,000 [[Engineering:Resistor|resistor]]s, 10,000 [[Engineering:Capacitor|capacitor]]s, and approximately 5,000,000 hand-[[Chemistry:Solder|solder]]ed joints. It weighed more than {{cvt|30|short ton|t|lk=in}}, was roughly {{cvt|8|feet|0}} tall, {{cvt|3|feet|0}} deep, and {{cvt|100|feet|0}} long, occupied {{cvt|300|sqft|m2}} and consumed 150&nbsp;kW of electricity.<ref>{{cite web |title=ENIAC |url=http://encyclopedia2.thefreedictionary.com/ENIAC |website=The Free Dictionary |access-date=2015-03-29}}</ref><ref name="BRLreport">{{cite book |last1=Weik |first1=Martin H. |title=Ballistic Research Laboratories Report No. 971: A Survey of Domestic Electronic Digital Computing Systems |date=December 1955 |publisher=United States Department of Commerce Office of Technical Services |location=Aberdeen Proving Ground, MD |page=41 |url=http://ed-thelen.org/comp-hist/BRL-e-h.html#ENIAC |access-date=2015-03-29}}</ref> Input was possible from an IBM card reader and an IBM card punch was used for output. These cards could be used to produce printed output offline using an [[Company:IBM|IBM]] accounting machine, such as the IBM 405. While ENIAC had no system to store memory in its inception, these punch cards could be used for external memory storage.<ref>{{cite web |url=http://www.seas.upenn.edu/about-seas/eniac/operation.php |title=ENIAC in Action: What it Was and How it Worked |website=ENIAC: Celebrating Penn Engineering History |publisher=University of Pennsylvania |access-date=2016-05-17}}</ref> In 1953, a 100-[[Word (computer architecture)|word]] [[Magnetic-core memory|magnetic-core memory]] built by the [[Company:Burroughs Corporation|Burroughs Corporation]] was added to ENIAC.<ref>{{cite web |url=https://www.cs.umd.edu/class/fall2001/cmsc411/projects/ramguide/pastandfuture/pastandfuture.html |title=Past and Future Developments in Memory Design |last=Martin |first=Jason |date=1998-12-17 |website=Past and Future Developments in Memory Design |publisher=University of Maryland |access-date=2016-05-17}}</ref>

ENIAC used [[Serial decimal|ten-position]] [[Ring counter|ring counter]]s to store digits; each digit required 36 vacuum tubes, 10 of which were the dual triodes making up the [[Engineering:Flip-flop (electronics)|flip-flops]] of the ring counter. Arithmetic was performed by "counting" pulses with the ring counters and generating carry pulses if the counter "wrapped around", the idea being to electronically emulate the operation of the digit wheels of a mechanical [[Engineering:Adding machine|adding machine]].<ref>{{Cite book |last=Peddie |first=Jon |url=https://books.google.com/books?id=6a8_AAAAQBAJ&q=ENIAC+used+ten-position+ring+counters+to+store+digits;+each+digit+required+36+vacuum+tubes,&pg=PA147 |title=The History of Visual Magic in Computers: How Beautiful Images are Made in CAD, 3D, VR and AR |date=2013-06-13 |publisher=Springer Science & Business Media |isbn=978-1-4471-4932-3 |language=en}}</ref>

ENIAC had 20 ten-digit signed [[Accumulator (computing)|accumulators]], which used ten's complement representation and could perform 5,000 simple addition or subtraction operations between any of them and a source (e.g., another accumulator or a constant transmitter) per second. It was possible to connect several accumulators to run simultaneously, so the peak speed of operation was potentially much higher, due to parallel operation.{{sfn|Goldstine|Goldstine|1946}}<ref>{{Cite book |last1=Igarashi |first1=Yoshihide |url=https://books.google.com/books?id=58ySAwAAQBAJ&q=ENIAC+had+20+ten-digit+signed+accumulators,+which+used+ten's+complement+representation&pg=PA154 |title=Computing: A Historical and Technical Perspective |last2=Altman |first2=Tom |last3=Funada |first3=Mariko |last4=Kamiyama |first4=Barbara |date=2014-05-27 |publisher=CRC Press |isbn=978-1-4822-2741-3 |language=en}}</ref>

[[Image:Classic shot of the ENIAC.jpg|thumb|250px|Cpl. Irwin Goldstein (foreground) sets the switches on one of ENIAC's function tables at the Moore School of Electrical Engineering. (U.S. Army photo)<ref>The original photo can be seen in the article: {{cite journal |last1=Rose |first1=Allen |title=Lightning Strikes Mathematics |journal=Popular Science |pages=83–86 |date=April 1946 |url=https://books.google.com/books?id=niEDAAAAMBAJ&pg=PA83 |access-date=2015-03-29}}</ref>]]

It was possible to wire the carry of one accumulator into another accumulator to perform arithmetic with double the precision, but the accumulator carry circuit timing prevented the wiring of three or more for even higher precision. ENIAC used four of the accumulators (controlled by a special multiplier unit) to perform up to 385 multiplication operations per second; five of the accumulators were controlled by a special divider/square-rooter unit to perform up to 40 division operations per second or three [[Square root|square root]] operations per second.

The other nine units in ENIAC were the initiating unit (started and stopped the machine), the cycling unit (used for synchronizing the other units), the master programmer (controlled loop sequencing), the reader (controlled an IBM punch-card reader), the printer (controlled an IBM card punch), the constant transmitter, and three function tables.{{sfn|Clippinger|1948|loc=Section I: General Description of the ENIAC – The Function Tables}}{{sfn|Goldstine|1946}}

===Operation times===
The references by Rojas and Hashagen (or Wilkes)<ref name="Wilkes"/> give more details about the times for operations, which differ somewhat from those stated above.

The basic machine cycle was 200 [[Microsecond|microsecond]]s (20 cycles of the 100&nbsp;kHz clock in the cycling unit), or 5,000 cycles per second for operations on the 10-digit numbers. In one of these cycles, ENIAC could write a number to a register, read a number from a register, or add/subtract two numbers.

A multiplication of a 10-digit number by a ''d''-digit number (for ''d'' up to 10) took ''d''+4 cycles, so the multiplication of a 10-digit number by 10-digit number took 14 cycles, or 2,800 microseconds—a rate of 357 per second. If one of the numbers had fewer than 10 digits, the operation was faster.

Division and square roots took 13(''d''+1) cycles, where ''d'' is the number of digits in the result (quotient or square root). So a division or square root took up to 143 cycles, or 28,600 microseconds—a rate of 35 per second. (Wilkes 1956:20<ref name="Wilkes"/> states that a division with a 10-digit quotient required 6 milliseconds.) If the result had fewer than ten digits, it was obtained faster.

ENIAC is able to process about 500 [[FLOPS]],<ref>{{Cite web |date=2019-03-18 |title=The incredible evolution of supercomputers' powers, from 1946 to today |url=https://www.popsci.com/supercomputers-then-and-now/ |access-date=2022-02-08 |website=Popular Science |language=en-US}}</ref> compared to [[Supercomputer#Performance metrics|modern supercomputers']] [[Petascale computing|petascale]] and [[Exascale computing|exascale]] computing power.

===Reliability===
ENIAC used common octal-base radio tubes of the day; the decimal [[Accumulator (computing)|accumulators]] were made of [[Engineering:6SN7|6SN7]] [[Engineering:Flip-flop (electronics)|flip-flops]], while 6L7s, 6SJ7s, 6SA7s and 6AC7s were used in logic functions.<ref>{{Harvnb|Burks|1947|pp=756–767}}</ref> Numerous [[Engineering:6L6|6L6]]s and [[Engineering:6V6|6V6]]s served as line drivers to drive pulses through cables between rack assemblies.

Several tubes burned out almost every day, leaving ENIAC nonfunctional about half the time. Special high-reliability tubes were not available until 1948. Most of these failures, however, occurred during the warm-up and cool-down periods, when the tube heaters and cathodes were under the most thermal stress. Engineers reduced ENIAC's tube failures to the more acceptable rate of one tube every two days. According to an interview in 1989 with Eckert, "We had a tube fail about every two days and we could locate the problem within 15 minutes."<ref>{{cite web |url=http://www.computerworld.com/s/article/108568/Q_A_A_lost_interview_with_ENIAC_co_inventor_J._Presper_Eckert |title=A lost interview with ENIAC co-inventor J. Presper Eckert |first=((Alexander 5th)) |last=Randall|publisher=Computer World |date=2006-02-14 |access-date=2015-03-29}}</ref>
In 1954, the longest continuous period of operation without a failure was 116 hours—close to five days.

==Programming==
ENIAC could be programmed to perform complex sequences of operations, including loops, branches, and subroutines. However, instead of the [[Stored-program computer|stored-program computer]]s that exist today, ENIAC was just a large collection of arithmetic machines, which originally had programs set up into the machine<ref>{{Cite journal |last=Grier |first=David |s2cid=7822223 |date=July–September 2004 |title=From the Editor's Desk |journal=IEEE Annals of the History of Computing |volume=26 |issue=3 |pages=2–3 |doi=10.1109/MAHC.2004.9}}</ref> by a combination of plugboard wiring and three portable function tables (containing 1,200 ten-way switches each).<ref>{{cite web |url=http://www.columbia.edu/cu/computinghistory/eniac.html |title=Programming the ENIAC |last=Cruz |first=Frank |date=2013-11-09 |website=Programming the ENIAC |publisher=Columbia University |access-date=2016-05-16}}</ref> The task of taking a problem and mapping it onto the machine was complex, and usually took weeks. Due to the complexity of mapping programs onto the machine, programs were only changed after huge numbers of tests of the current program.<ref>{{Cite journal |last=Alt |first=Franz |date=July 1972 |title=Archaeology of computers: reminiscences, 1945-1947 |journal=Communications of the ACM |volume=15 |issue=7 |pages=693–694 |doi=10.1145/361454.361528 |s2cid=28565286|doi-access=free }}</ref> After the program was figured out on paper, the process of getting the program into ENIAC by manipulating its switches and cables could take days. This was followed by a period of verification and debugging, aided by the ability to execute the program step by step. A programming tutorial for the modulo function using an ENIAC simulator gives an impression of what a program on the ENIAC looked like.<ref>{{cite web |url=http://placebo.hpi.uni-potsdam.de/webhome/matthieu.schapranow/eniac/modulo/ |archive-url=https://web.archive.org/web/20140107125516/http://placebo.hpi.uni-potsdam.de/webhome/matthieu.schapranow/eniac/modulo/ |url-status=dead |archive-date=7 January 2014 |title=ENIAC tutorial - the modulo function |first=Matthieu-P. |last=Schapranow |date=1 June 2006 |access-date=2017-03-04}}</ref><ref>Description of Lehmer's program computing the exponent of modulo 2 prime</ref><ref>{{harvnb|De Mol|Bullynck|2008}}</ref>

ENIAC's six primary programmers, [[Biography:Kathleen Antonelli|Kay McNulty]], [[Biography:Jean Bartik|Betty Jennings]], [[Biography:Betty Holberton|Betty Snyder]], [[Biography:Marlyn Meltzer|Marlyn Wescoff]], [[Biography:Frances Spence|Fran Bilas]] and [[Biography:Ruth Teitelbaum|Ruth Lichterman]], not only determined how to input ENIAC programs, but also developed an understanding of ENIAC's inner workings.<ref>{{cite web |url=http://eniacprogrammers.org/eniac-programmers-project/ |title=ENIAC Programmers Project |publisher=eniacprogrammers.org |access-date=2015-03-29}}</ref><ref>{{cite web |last=Donaldson James |first=Susan |title=First Computer Programmers Inspire Documentary |url=https://abcnews.go.com/Technology/story?id=3951187&page=1&singlePage=true |work=ABC News |access-date=2015-03-29 |date=2007-12-04}}</ref> The programmers were often able to narrow bugs down to an individual failed tube which could be pointed to for replacement by a technician.<ref>{{cite journal |last=Fritz |first=W. Barkley |title=The Women of ENIAC |journal=IEEE Annals of the History of Computing |date=1996 |volume=18 |issue=3 |pages=13–28 |url=http://www.eg.bucknell.edu/~csci203/2012-fall/hw/hw06/assets/womenOfENIAC.pdf |access-date=2015-04-12 |doi=10.1109/85.511940 |url-status=dead |archive-url=https://web.archive.org/web/20160304052225/http://www.eg.bucknell.edu/~csci203/2012-fall/hw/hw06/assets/womenOfENIAC.pdf |archive-date=2016-03-04}}</ref>

===Programmers===
[[Image:Two women operating ENIAC (full resolution).jpg|thumb|250px|Programmers Betty Jean Jennings (left) and Fran Bilas (right) operating ENIAC's main control panel at the Moore School of Electrical Engineering, {{c.}} 1945. (U.S. Army photo from the archives of the ARL Technical Library)]]
{{Listen|type=speech|pos=right|filename=The ENIAC Programmers (As Told By U.S. Chief Technology Officer Megan Smith).ogg|title=The ENIAC Programmers (As Told By U.S. Chief Technology Officer Megan Smith)|description=}}

During [[Social:World War II|World War II]], while the U.S. Army needed to compute ballistics trajectories, many women were interviewed for this task. At least 200 women were hired by the Moore School of Engineering to work as "[[Computer (job description)|computer]]s"{{sfn|Light|1999}} and six of them were chosen to be the programmers of ENIAC. [[Biography:Betty Holberton|Betty Holberton]], [[Biography:Kathleen Antonelli|Kay McNulty]], [[Biography:Marlyn Meltzer|Marlyn Wescoff]], [[Biography:Ruth Teitelbaum|Ruth Lichterman]], [[Biography:Jean Bartik|Betty Jean Jennings]], and [[Biography:Frances Spence|Fran Bilas]], programmed the ENIAC to perform calculations for ballistics trajectories electronically for the Army's Ballistic Research Laboratory.<ref name="SWE-Spr19">{{cite news |last1=McCabe |first1=Seabright |title=The Programming Pioneers of ENIAC |url=https://drive.google.com/file/d/11_csuKxT-rprQO1CvlGEP0pBl1-1TcRT/view |url-status=live |archive-date=2023-12-25 |archive-url=https://web.archive.org/web/20231225110455/https://drive.google.com/file/d/11_csuKxT-rprQO1CvlGEP0pBl1-1TcRT/view |access-date=July 8, 2020 |work=All Together |issue=Spring 2019 |publisher=Society of Women Engineers |date=June 3, 2019}}</ref> While men having the same education and experience were designated as "professionals", these women were unreasonably designated as "subprofessionals", though they had professional degrees in mathematics, and were highly trained mathematicians.<ref name="SWE-Spr19" />

These women were not, as computer scientist and historian Kathryn Kleiman was once told, "refrigerator ladies", i.e., models posing in front of the machine for press photography.<ref name="refrigerator">{{cite web |url=http://mentalfloss.com/article/53160/meet-refrigerator-ladies-who-programmed-eniac |title=Meet the 'Refrigerator Ladies' Who Programmed the ENIAC |website=Mental Floss |access-date=2016-06-16 |date=2013-10-13}}</ref> However, some of the women did not receive recognition for their work on the ENIAC in their entire lifetimes.{{sfn|Light|1999}} After the war ended, the women continued to work on the ENIAC. Their expertise made their positions difficult to replace with returning soldiers.<ref>{{cite web |title=ENIAC Programmers: A History of Women in Computing |url=https://spin.atomicobject.com/2016/07/31/eniac-programmers/ |website=Atomic Spin |date=31 July 2016}}</ref>

These early programmers were drawn from a group of about two hundred women employed as [[Computer (occupation)|computers]] at the Moore School of Electrical Engineering at the University of Pennsylvania. The job of computers was to produce the numeric result of mathematical formulas needed for a scientific study, or an engineering project. They usually did so with a mechanical calculator. The women studied the machine's logic, physical structure, operation, and circuitry in order to not only understand the mathematics of computing, but also the machine itself.{{sfn|Light|1999}} This was one of the few technical job categories available to women at that time.<ref>{{cite book |last=Grier |first=David |title=When Computers Were Human |publisher=Princeton University Press |date=2007 |isbn=9781400849369 |url=https://archive.org/details/whencomputerswer00davi |access-date=2016-11-24}}</ref> [[Biography:Betty Holberton|Betty Holberton]] (née Snyder) continued on to help write the first generative programming system ([[Mainframe sort merge|SORT/MERGE]]) and help design the first commercial electronic computers, the [[Engineering:UNIVAC|UNIVAC]] and the BINAC, alongside Jean Jennings.<ref name="beyer">{{cite book |title=Grace Hopper and the Invention of the Information Age |last1=Beyer |first1=Kurt |date=2012 |publisher=MIT Press |isbn=9780262517263 |location=London, Cambridge |page=198}}</ref> McNulty developed the use of [[Subroutine|subroutine]]s in order to help increase ENIAC's computational capability.<ref name=":4">{{cite web |url=http://fortune.com/2014/09/18/walter-isaacson-the-women-of-eniac/ |title=Walter Isaacson on the Women of ENIAC |last=Isaacson |first=Walter |date=18 September 2014 |website=Fortune |archive-url=https://web.archive.org/web/20181212003245/http://fortune.com/2014/09/18/walter-isaacson-the-women-of-eniac/ |archive-date=12 December 2018 |access-date=2018-12-14}}</ref>

[[Biography:Herman Goldstine|Herman Goldstine]] selected the programmers, whom he called operators, from the computers who had been calculating ballistics tables with mechanical desk calculators, and a differential analyzer prior to and during the development of ENIAC.{{sfn|Light|1999}} Under Herman and [[Biography:Adele Goldstine|Adele Goldstine]]'s direction, the computers studied ENIAC's blueprints and physical structure to determine how to manipulate its switches and cables, as [[Programming language|programming language]]s did not yet exist. Though contemporaries considered programming a clerical task and did not publicly recognize the programmers' effect on the successful operation and announcement of ENIAC,{{sfn|Light|1999}} McNulty, Jennings, Snyder, Wescoff, Bilas, and Lichterman have since been recognized for their contributions to computing.<ref name="invisible"/><ref name="secret"/><ref name="siff"/> Three of the current (2020) Army supercomputers ''Jean'', ''Kay'', and ''Betty'' are named after [[Biography:Jean Bartik|Jean Bartik]] (Betty Jennings), [[Biography:Kathleen Antonelli|Kay McNulty]], and [[Biography:Betty Holberton|Betty Snyder]] respectively.<ref>{{cite web |url=https://www.army.mil/article/242062/army_researchers_acquire_two_new_supercomputers |title=Army researchers acquire two new supercomputers |website=U.S. Army DEVCOM Army Research Laboratory Public Affairs |date=December 28, 2020 |access-date=March 1, 2021}}</ref>

The "programmer" and "operator" job titles were not originally considered professions suitable for women. The labor shortage created by World War II helped enable the entry of women into the field.{{sfn|Light|1999}} However, the field was not viewed as prestigious, and bringing in women was viewed as a way to free men up for more skilled labor. Essentially, women were seen as meeting a need in a temporary crisis.{{sfn|Light|1999}} For example, the National Advisory Committee for Aeronautics said in 1942, "It is felt that enough greater return is obtained by freeing the engineers from calculating detail to overcome any increased expenses in the computers' salaries. The engineers admit themselves that the girl computers do the work more rapidly and accurately than they would. This is due in large measure to the feeling among the engineers that their college and industrial experience is being wasted and thwarted by mere repetitive calculation".{{sfn|Light|1999}}

Following the initial six programmers, an expanded team of a hundred scientists was recruited to continue work on the ENIAC. Among these were several women, including [[Biography:Gloria Gordon Bolotsky|Gloria Ruth Gordon]].<ref name="wapobit">{{cite news |newspaper={{wipe|The Washington Post}} |url=https://www.washingtonpost.com/wp-dyn/content/article/2009/07/25/AR2009072502045.html |title=Gloria Gordon Bolotsky, 87; Programmer Worked on Historic ENIAC Computer |last=Sullivan |first=Patricia |date=2009-07-26 |access-date=2015-08-19}}</ref> Adele Goldstine wrote the original technical description of the ENIAC.<ref>{{cite web |url=https://www.arl.army.mil/www/default.cfm?page=148 |title=ARL Computing History &#124; U.S. Army Research Laboratory |publisher=Arl.army.mil |access-date=2019-06-29}}</ref>

=== Programming languages ===

Several language systems were developed to describe programs for the ENIAC, including:

{|
|-
! Year
! Name
! Chief developers
|-
| 1943–46
| ENIAC coding system
| [[Biography:John von Neumann|John von Neumann]], [[Biography:John Mauchly|John Mauchly]], [[Biography:J. Presper Eckert|J. Presper Eckert]], [[Biography:Herman Goldstine|Herman Goldstine]] after [[Biography:Alan Turing|Alan Turing]].
|-
| 1946
| ENIAC Short Code
| Richard Clippinger, [[Biography:John von Neumann|John von Neumann]] after [[Biography:Alan Turing|Alan Turing]]
|-
| 1946
| Von Neumann and Goldstine graphing system (Notation)
| [[Biography:John von Neumann|John von Neumann]] and [[Biography:Herman Goldstine|Herman Goldstine]]
|-
| 1947
| ARC Assembly
| [[Biography:Kathleen Booth|Kathleen Booth]]<ref>{{cite journal|last=Booth|first=Kathleen|title=Machine Language for Automatic Relay Computer|journal=Birkbeck College Computation Laboratory|publisher=University of London}}</ref><ref>Campbell-Kelly, Martin "The Development of Computer Programming in Britain (1945 to 1955)", The Birkbeck College Machines, in (1982) Annals of the History of Computing 4(2) April 1982 IEEE</ref>
|-
| 1948
| Curry notation system
| [[Biography:Haskell Curry|Haskell Curry]]
|}

===Role in the hydrogen bomb===
Although the Ballistic Research Laboratory was the sponsor of ENIAC, one year into this three-year project [[Biography:John von Neumann|John von Neumann]], a mathematician working on the hydrogen bomb at [[Organization:Los Alamos National Laboratory|Los Alamos National Laboratory]], became aware of the ENIAC.<ref>{{Harvnb|Goldstine|1993|page=182}}</ref> In December 1945, the ENIAC was used to calculate thermonuclear reactions using [[Equation|equation]]s. The data was used to support research on building a hydrogen bomb.<ref>{{cite book |first=Jeffrey R. |last=Yost |title=Making IT Work: A History of the Computer Services Industry |publisher=MIT Press |year=2017 |page=19 |isbn=9780262036726}}</ref>

===Role in development of the Monte Carlo methods===
Related to ENIAC's role in the hydrogen bomb was its role in the [[Monte Carlo method]] becoming popular. Scientists involved in the original nuclear bomb development used massive groups of people doing huge numbers of calculations ("computers" in the terminology of the time) to investigate the distance that neutrons would likely travel through various materials. [[Biography:John von Neumann|John von Neumann]] and [[Biography:Stanislaw Ulam|Stanislaw Ulam]] realized the speed of ENIAC would allow these calculations to be done much more quickly.<ref name="mbv01">{{Cite book |last1=Mazhdrakov |first1=Metodi |last2=Benov |first2=Dobriyan |last3=Valkanov |first3=Nikolai |year=2018 |title=The Monte Carlo Method. Engineering Applications |publisher=ACMO Academic Press |page=250 |isbn=978-619-90684-3-4 |url=https://books.google.com/books?id=t0BqDwAAQBAJ&q=the+monte+carlo+method+engineering+applications+mazhdrakov}}</ref> The success of this project showed the value of Monte Carlo methods in science.<ref>{{Cite book |title=The Disappearing Spoon |last=Kean |first=Sam |publisher=Little, Brown and Company |date=2010 |isbn=978-0-316-05163-7 |location=New York |pages=109–111}}</ref>

==Later developments==
A press conference was held on February 1, 1946,{{sfn|Light|1999}} and the completed machine was announced to the public the evening of February 14, 1946,<ref>{{cite news |title=Electronic Computer Flashes Answers | last=Kennedy | first=T. R. Jr. |date=1946-02-15 |newspaper=New York Times |url=http://learn.fi.edu/learn/case-files/eckertmauchly/design.html |access-date=2015-03-29 |archive-url=https://web.archive.org/web/20150710220137/http://learn.fi.edu/learn/case-files/eckertmauchly/design.html |archive-date=2015-07-10 |url-status=dead}}</ref> featuring demonstrations of its capabilities. Elizabeth Snyder and Betty Jean Jennings were responsible for developing the demonstration trajectory program, although Herman and Adele Goldstine took credit for it.{{sfn|Light|1999}} The machine was formally dedicated the next day<ref>{{cite court |litigants=Honeywell, Inc. v. Sperry Rand Corp. |vol=180 |reporter=U.S.P.Q. (BNA) |opinion=673 |pinpoint=p. 20, finding 1.1.3 |court=U.S. District Court for the District of Minnesota, Fourth Division |date=1973 |url=http://www.ushistory.org/more/eniac/public.htm |quote=The ENIAC machine which embodied 'the invention' claimed by the ENIAC patent was in public use and non-experimental use for the following purposes, and at times prior to the critical date: ... Formal dedication use February 15, 1946 ...}}</ref> at the University of Pennsylvania. None of the women involved in programming the machine or creating the demonstration were invited to the formal dedication nor to the celebratory dinner held afterwards.<ref>{{Cite book |title=Broad Band: The Untold Story of the Women Who Made the Internet |last=Evans |first=Claire L. |date=2018-03-06 |publisher=Penguin |isbn=9780735211766 |page=51 |url=https://books.google.com/books?id=C8ouDwAAQBAJ&q=broad%20band%20evans&pg=PP1}}</ref>

The original contract amount was $61,700; the final cost was almost $500,000 (approximately {{Inflation|US|487000|1943|fmt=eq|r=-6}}). It was formally accepted by the U.S. Army Ordnance Corps in July 1946. ENIAC was shut down on November 9, 1946, for a refurbishment and a memory upgrade, and was transferred to Aberdeen Proving Ground, Maryland in 1947. There, on July 29, 1947, it was turned on and was in continuous operation until 11:45&nbsp;p.m. on October 2, 1955, when it was retired in favor of the more efficient EDVAC and ORDVAC computers.<ref name="ENIACstory" />

===Role in the development of the EDVAC===
A few months after ENIAC's unveiling in the summer of 1946, as part of "an extraordinary effort to jump-start research in the field",<ref name="Mac">{{harvnb|McCartney|1999|p=140}}</ref> the Pentagon invited "the top people in electronics and mathematics from the United States and Great Britain"<ref name="Mac"/> to a series of forty-eight lectures given in Philadelphia, Pennsylvania; all together called ''The Theory and Techniques for Design of Digital Computers''—more often named the Moore School Lectures.<ref name="Mac"/> Half of these lectures were given by the inventors of ENIAC.<ref>{{harvnb|McCartney|1999|p=140}}: "Eckert gave eleven lectures, Mauchly gave six, Goldstine gave six. von Neumann, who was to give one lecture, didn't show up; the other 24 were spread among various invited academics and military officials."</ref>

ENIAC was a one-of-a-kind design and was never repeated. The freeze on design in 1943 meant that it lacked some innovations that soon became well-developed, notably the ability to store a program. Eckert and Mauchly started work on a new design, to be later called the EDVAC, which would be both simpler and more powerful. In particular, in 1944 Eckert wrote his description of a memory unit (the mercury [[Delay-line memory|delay line]]) which would hold both the data and the program. John von Neumann, who was consulting for the Moore School on the EDVAC, sat in on the Moore School meetings at which the stored program concept was elaborated. Von Neumann wrote up an incomplete set of notes (''First Draft of a Report on the EDVAC'') which were intended to be used as an internal memorandum—describing, elaborating, and couching in formal logical language the ideas developed in the meetings. ENIAC administrator and security officer [[Biography:Herman Goldstine|Herman Goldstine]] distributed copies of this ''First Draft'' to a number of government and educational institutions, spurring widespread interest in the construction of a new generation of electronic computing machines, including Electronic Delay Storage Automatic Calculator (EDSAC) at Cambridge University, England and SEAC at the U.S. Bureau of Standards.<ref name=":2" />

===Improvements===
A number of improvements were made to ENIAC after 1947, including a primitive read-only stored programming mechanism using the function tables as program [[Read-only memory|ROM]],<ref name=":2" />{{sfn|Goldstine|1947}}<ref>{{harvnb|Goldstine|1993|pp=233–234, 270|loc=search string: "eniac Adele 1947"}}</ref><ref>By July 1947 von Neumann was writing: "I am much obliged to Adele for her letters. Nick and I are working with her new code, and it seems excellent."</ref><ref>{{harvnb|Clippinger|1948|loc=Section IV: Summary of Orders}}</ref><ref>{{harvnb|Haigh|Priestley|Rope|2014b|pp=44–48}}</ref> after which programming was done by setting the switches.<ref>{{cite book |last1=Pugh |first1=Emerson W. |title=Building IBM: Shaping an Industry and Its Technology |date=1995 |publisher=MIT Press |isbn=9780262161473 |page=353 |chapter-url=https://books.google.com/books?id=Bc8BGhSOawgC&q=eniac%20rewiring&pg=PA353 |chapter=Notes to Pages 132-135}}</ref> The idea has been worked out in several variants by Richard Clippinger and his group, on the one hand, and the Goldstines, on the other,{{sfn|Haigh|Priestley|Rope|2014b|pp=44-45}} and it was included in the ENIAC patent.{{sfn|Haigh|Priestley|Rope|2014b|p=44}} Clippinger consulted with von Neumann on what instruction set to implement.<ref name=":2" />{{sfn|Clippinger|1948|loc=INTRODUCTION}}{{sfn|Goldstine|1993|p=|loc=233-234, 270; search string: ''eniac Adele 1947''}} Clippinger had thought of a three-address architecture while von Neumann proposed a one-address architecture because it was simpler to implement. Three digits of one accumulator (#6) were used as the program counter, another accumulator (#15) was used as the main accumulator, a third accumulator (#8) was used as the address pointer for reading data from the function tables, and most of the other accumulators (1–5, 7, 9–14, 17–19) were used for data memory.

In March 1948 the converter unit was installed,{{sfn|Haigh|Priestley|Rope|2014b|pp=47-48}} which made possible programming through the reader from standard IBM cards.{{sfn|Clippinger|1948|loc=Section VIII: Modified ENIAC}}<ref>{{cite journal |last1=Fritz |first1=W. Barkley |title=Description and Use of the ENIAC Converter Code |journal=Technical Note |date=1949 |issue=141 |url=http://eniacinaction.com/the-articles/2-engineering-the-miracle-of-the-eniac-implementing-the-modern-code-paradigm/ |at=Section 1. – Introduction, p. 1 |quote=At present it is controlled by a code which incorporates a unit called the Converter as a basic part of its operation, hence the name ENIAC Converter Code. These code digits are brought into the machine either through the Reader from standard IBM cards*or from the Function Tables (...). (...) *The card control method of operation is used primarily for testing and the running of short highly iterative problems and is not discussed in this report.}}</ref> The "first production run" of the new coding techniques on the [[Monte Carlo method|Monte Carlo]] problem followed in April.{{sfn|Haigh|Priestley|Rope|2014b|pp=47-48}}<ref>{{Cite journal |url=http://eniacinaction.com/the-articles/3-los-alamos-bets-on-eniac-nuclear-monte-carlo-simulations-1947-8/ |title=Los Alamos Bets On ENIAC: Nuclear Monte Carlo Simulations 1947-48 |last1=Haigh |first1=Thomas |last2=Priestley |first2=Mark |last3=Rope |first3=Crispin |date=July–September 2014c |volume=36 |issue=3 |pages=42–63 |journal=IEEE Annals of the History of Computing |access-date=2018-11-13 |doi=10.1109/MAHC.2014.40 |s2cid=17470931}}</ref> After ENIAC's move to Aberdeen, a register panel for memory was also constructed, but it did not work. A small master control unit to turn the machine on and off was also added.{{sfn|Haigh|Priestley|Rope|2016|pp=113–114}}

The programming of the stored program for ENIAC was done by Betty Jennings, Clippinger, Adele Goldstine and others.<ref>{{harvnb|Clippinger|1948|loc=INTRODUCTION}}</ref><ref>{{harvnb|Haigh|Priestley|Rope|2014b|p=44}}</ref>{{sfn|Goldstine|1947}}<ref name=":2" /> It was first demonstrated as a [[Stored-program computer|stored-program computer]] in April 1948,{{sfn|Haigh|Priestley|Rope|2016|p=153}} running a program by [[Biography:Adele Goldstine|Adele Goldstine]] for John von Neumann. This modification reduced the speed of ENIAC by a factor of 6 and eliminated the ability of parallel computation, but as it also reduced the reprogramming time{{sfn|Goldstine|1993|p=|loc=233-234, 270; search string: ''eniac Adele 1947''}}<ref name=":2" /> to hours instead of days, it was considered well worth the loss of performance. Also analysis had shown that due to differences between the electronic speed of computation and the electromechanical speed of input/output, almost any real-world problem was completely I/O bound, even without making use of the original machine's parallelism. Most computations would still be I/O bound, even after the speed reduction imposed by this modification.

Early in 1952, a high-speed shifter was added, which improved the speed for shifting by a factor of five. In July 1953, a 100-word expansion [[Magnetic-core memory|core memory]] was added to the system, using [[Binary-coded decimal|binary-coded decimal]], [[Excess-3|excess-3]] number representation. To support this expansion memory, ENIAC was equipped with a new Function Table selector, a memory address selector, pulse-shaping circuits, and three new orders were added to the programming mechanism.<ref name=":2">{{cite web |url=http://epictechnologyforgreatjustice.weebly.com/eniac.html |title=Eniac |website=Epic Technology for Great Justice |access-date=2017-01-28}}</ref>

==Comparison with other early computers==
{{main|History of computing hardware}}
<!--THIS ARTICLE IS ABOUT ENIAC. If you wish to add very detailed material about other computers, please consider adding it to that computer's own article or [[History of computing hardware]]. Happy editing! -->

Mechanical computing machines have been around since [[Biography:Archimedes|Archimedes]]' time (see: [[Astronomy:Antikythera mechanism|Antikythera mechanism]]), but the 1930s and 1940s are considered the beginning of the modern computer era.

ENIAC was, like the IBM [[Engineering:Harvard Mark I|Harvard Mark I]] and the German Z3, able to run an arbitrary sequence of mathematical operations, but did not read them from a tape. Like the British [[Engineering:Colossus computer|Colossus]], it was programmed by plugboard and switches. ENIAC combined full, Turing-complete programmability with electronic speed. The Atanasoff–Berry Computer (ABC), ENIAC, and Colossus all used [[Physics:Vacuum tube|thermionic valves (vacuum tubes)]]. ENIAC's registers performed decimal arithmetic, rather than binary arithmetic like the Z3, the ABC and Colossus.

Like the Colossus, ENIAC required rewiring to reprogram until April 1948.<ref>See #Improvements</ref> In June 1948, the Manchester Baby ran its first program and earned the distinction of first electronic [[Stored-program computer|stored-program computer]].<ref>{{cite web |title=Programming the ENIAC: an example of why computer history is hard {{!}} @CHM Blog |date=2016-05-18 |website=Computer History Museum |url= https://www.computerhistory.org/atchm/programming-the-eniac-an-example-of-why-computer-history-is-hard/}}</ref><ref>{{cite journal |last1=Haigh |first1=Thomas |last2=Priestley |first2=Mark |last3=Rope |first3=Crispin |date=January–March 2014a |title=Reconsidering the Stored Program Concept |url=http://eniacinaction.com/the-articles/1-reconsidering-the-stored-program-concept/ |journal=IEEE Annals of the History of Computing |volume=36 |issue=1 |pages=9–10 |doi=10.1109/mahc.2013.56 |s2cid=18827916}}</ref>{{sfn|Haigh|Priestley|Rope|2014b|pp=48-54}} Though the idea of a stored-program computer with combined memory for program and data was conceived during the development of ENIAC, it was not initially implemented in ENIAC because World War II priorities required the machine to be completed quickly, and ENIAC's 20 storage locations would be too small to hold data and programs.

===Public knowledge===
The Z3 and Colossus were developed independently of each other, and of the ABC and ENIAC during World War II. Work on the ABC at [[Organization:Iowa State University|Iowa State University]] was stopped in 1942 after John Atanasoff was called to [[Place:Washington, D.C.|Washington, D.C.]], to do physics research for the U.S. Navy, and it was subsequently dismantled.{{sfn|Copeland|2006|p=106}} The Z3 was destroyed by the Allied bombing raids of Berlin in 1943. As the ten Colossus machines were part of the UK's war effort their existence remained secret until the late 1970s, although knowledge of their capabilities remained among their UK staff and invited Americans. ENIAC, by contrast, was put through its paces for the press in 1946, "and captured the world's imagination". Older histories of computing may therefore not be comprehensive in their coverage and analysis of this period. All but two of the Colossus machines were dismantled in 1945; the remaining two were used to decrypt Soviet messages by [[Organization:GCHQ|GCHQ]] until the 1960s.{{sfn|Copeland|2006|p=2}}<ref>{{Citation |last=Ward |first=Mark |title=How GCHQ built on a colossal secret |work=BBC News |date=5 May 2014 |url=https://www.bbc.co.uk/news/technology-26714967}}</ref> The public demonstration for ENIAC was developed by Snyder and Jennings who created a demo that would calculate the trajectory of a missile in 15 seconds, a task that would have taken several weeks for a [[Human computer|human computer]].<ref name=":4" />

===Patent===
For a variety of reasons{{snd}}including Mauchly's June 1941 examination of the Atanasoff–Berry computer (ABC), prototyped in 1939 by John Atanasoff and [[Biography:Clifford Berry|Clifford Berry]]{{snd}}{{US patent|3120606}} for ENIAC, applied for in 1947 and granted in 1964, was voided by the 1973<ref>{{cite web| url = https://jva.cs.iastate.edu/courtcase.php | title = Atanasoff-Berry Computer Court Case | access-date = 2022-09-01}}</ref> decision of the landmark federal court case ''Honeywell, Inc. v. Sperry Rand Corp.''. The decision included: that the ENIAC inventors had derived the subject matter of the electronic digital computer from Atanasoff;  gave legal recognition to Atanasoff as the inventor of the first electronic digital computer; and put the invention of the electronic digital computer in the [[Social:Public domain|public domain]].

==Main parts==
[[File:ENIAC, Ft. Sill, OK, US (78).jpg|right|thumb|The bottoms of three accumulators at Fort Sill, Oklahoma, US]]
[[File:ENIAC function table at Aberdeen.jpg|thumb|A function table from ENIAC on display at Aberdeen Proving Ground museum.]]
The main parts were 40 panels and three portable function tables (named A, B, and C). The layout of the panels was (clockwise, starting with the left wall):
;Left wall
* Initiating Unit
* Cycling Unit
* Master Programmer – panel 1 and 2
* Function Table 1 – panel 1 and 2
* Accumulator 1
* Accumulator 2
* Divider and Square Rooter
* Accumulator 3
* Accumulator 4
* Accumulator 5
* Accumulator 6
* Accumulator 7
* Accumulator 8
* Accumulator 9

; Back wall
* Accumulator 10
* High-speed Multiplier – panel 1, 2, and 3
* Accumulator 11
* Accumulator 12
* Accumulator 13
* Accumulator 14

; Right wall
* Accumulator 15
* Accumulator 16
* Accumulator 17
* Accumulator 18
* Function Table 2 – panel 1 and 2
* Function Table 3 – panel 1 and 2
* Accumulator 19
* Accumulator 20
* Constant Transmitter – panel 1, 2, and 3
* Printer – panel 1, 2, and 3
An IBM card reader was attached to Constant Transmitter panel 3 and an IBM card punch was attached to Printer Panel 2. The Portable Function Tables could be connected to Function Table 1, 2, and 3.{{sfn|Haigh|Priestley|Rope|2016|pp=46, 264}}

===Parts on display===
[[File:ENIAC Penn2.jpg|thumb|250px|Detail of the back of a section of ENIAC, showing vacuum tubes]]
Pieces of ENIAC are held by the following institutions:
* The School of Engineering and Applied Science at the University of Pennsylvania has four of the original forty panels (Accumulator #18, Constant Transmitter Panel 2, Master Programmer Panel 2, and the Cycling Unit) and one of the three function tables (Function Table B) of ENIAC (on loan from the Smithsonian).{{sfn|Haigh|Priestley|Rope|2016|pp=46, 264}}
* The Smithsonian has five panels (Accumulators 2, 19, and 20; Constant Transmitter panels 1 and 3; Divider and Square Rooter; Function Table 2 panel 1; Function Table 3 panel 2; High-speed Multiplier panels 1 and 2; Printer panel 1; Initiating Unit){{sfn|Haigh|Priestley|Rope|2016|pp=46, 264}} in the National Museum of American History in Washington, D.C.{{sfn|Light|1999}} (but apparently not currently on display).
* The Science Museum in London has a receiver unit on display.
* The Computer History Museum in Mountain View, California has three panels (Accumulator #12, Function Table 2 panel 2, and Printer Panel 3) and portable function table C on display (on loan from the Smithsonian Institution).{{sfn|Haigh|Priestley|Rope|2016|pp=46, 264}}
* The [[Organization:University of Michigan|University of Michigan]] in Ann Arbor has four panels (two accumulators, High-speed Multiplier panel 3, and Master Programmer panel 2),{{sfn|Haigh|Priestley|Rope|2016|pp=46, 264}} salvaged by [[Biography:Arthur Burks|Arthur Burks]].
* The United States Army Ordnance Museum at Aberdeen Proving Ground, Maryland, where ENIAC was used, has Portable Function Table A.
* The U.S. Army Field Artillery Museum in Fort Sill, as of October 2014, obtained seven panels of ENIAC that were previously housed by The Perot Group in Plano, Texas.<ref>{{cite news |last1=Meador |first1=Mitch |title=ENIAC: First Generation Of Computation Should Be A Big Attraction At Sill |date=2014-10-29 |work=The Lawton Constitution |url=http://www.swoknews.com/local/eniac-first-generation-computation-should-be-big-attraction-sill |access-date=2015-04-08 |archive-date=April 6, 2015 |archive-url=https://web.archive.org/web/20150406033844/http://www.swoknews.com/local/eniac-first-generation-computation-should-be-big-attraction-sill |url-status=dead }}</ref> There are accumulators #7, #8, #11, and #17;<ref>Haigh. ''et al.'' list accumulators 7, 8, 13, and 17, but 2018 photos show 7, 8, 11, and 17.{{full citation needed|date=October 2020}}</ref> panel #1 and #2 that connected to function table #1,{{sfn|Haigh|Priestley|Rope|2016|pp=46, 264}} and the back of a panel showing its tubes. A module of tubes is also on display.
* The United States Military Academy at West Point, New York, has one of the data entry terminals from the ENIAC.
* The Heinz Nixdorf Museum in Paderborn, Germany, has three panels (Printer panel 2 and High-speed Function Table){{sfn|Haigh|Priestley|Rope|2016|pp=46, 264}} (on loan from the Smithsonian Institution). In 2014 the museum decided to rebuild one of the accumulator panels – reconstructed part has the look and feel of a simplified counterpart from the original machine.<ref>{{cite web |title=Meet the iPhone's 30-ton ancestor: Inside the project to rebuild one of the first computers |url=https://www.techrepublic.com/article/meet-the-iphones-30-ton-ancestor-inside-the-project-to-rebuild-one-of-the-first-computers/ |website=TechRepublic |date=November 23, 2016 |at=Bringing the Eniac back to life}}</ref><ref>{{cite web |url=http://www.hnf.de/en/museum/die-erfindung-des-computers/eniac-life-size-model-of-the-first-vacuum-tube-computer.html |title=ENIAC – Life-size model of the first vacuum-tube computer |publisher=Heinz Nixdorf Museum |location=Germany |access-date=March 1, 2021 |archive-date=November 5, 2016 |archive-url=https://web.archive.org/web/20161105172749/http://www.hnf.de/en/museum/die-erfindung-des-computers/eniac-life-size-model-of-the-first-vacuum-tube-computer.html |url-status=dead }}</ref>

==Recognition==
ENIAC was named an IEEE Milestone in 1987.<ref>{{cite web |url=http://www.ieeeghn.org/wiki/index.php/Milestones:Electronic_Numerical_Integrator_and_Computer,_1946 |title=Milestones:Electronic Numerical Integrator and Computer, 1946 |work=IEEE Global History Network |publisher=IEEE |access-date=2011-08-03}}</ref>

[[File:ENIAC on a Chip, University of Pennsylvania (1995) - Computer History Museum.jpg|ENIAC on a Chip, University of Pennsylvania (1995) - Computer History Museum|thumb]]
In 1996, in honor of the ENIAC's 50th anniversary, The [[Organization:University of Pennsylvania|University of Pennsylvania]] sponsored a project named "ENIAC-on-a-Chip", where a very small [[Engineering:Integrated circuit|silicon computer chip]] measuring 7.44&nbsp;mm by 5.29&nbsp;mm was built with the same functionality as ENIAC. Although this 20&nbsp;MHz chip was many times faster than ENIAC, it had but a fraction of the speed of its contemporary microprocessors in the late 1990s.<ref>{{cite news |title=Looking Back At ENIAC: Commemorating A Half-Century Of Computers In The Reviewing System |url=https://www.the-scientist.com/news/looking-back-at-eniac-commemorating-a-half-century-of-computers-in-the-reviewing-system-58406 |work=The Scientist Magazine}}</ref><ref>{{Cite magazine |url=http://www.upenn.edu/computing/printout/archive/v12/4/chip.html |access-date=2016-10-17 |magazine=PENN PRINTOUT |publisher=The University of Pennsylvania |last=Van Der Spiegel |first=Jan |date=1996 |archive-url= https://web.archive.org/web/20121011185032/http://www.upenn.edu/computing/printout/archive/v12/4/chip.html |archive-date=2012-10-11 |url-status=dead |title=ENIAC-on-a-Chip |volume=12 |issue=4}}</ref><ref>{{cite web |title=ENIAC-on-a-Chip |url=http://www.seas.upenn.edu/~jan/eniacproj.html |access-date=2009-09-04 |publisher=University of Pennsylvania |date=1995-05-09 |first=Jan |last=Van Der Spiegel}}</ref>

In 1997, the six women who did most of the programming of ENIAC were inducted into the Technology International Hall of Fame.<ref name="invisible">{{cite web |url=http://www.witi.com/wire/articles/3/Invisible-Computers:-The-Untold-Story-of-the-ENIAC-Programmers/1/ |title=Invisible Computers: The Untold Story of the ENIAC Programmers |publisher=Witi.com |access-date=2015-03-10}}</ref><ref name="proto">{{cite news |url=http://archive.wired.com/culture/lifestyle/news/1997/05/3711 |title=Wired: Women Proto-Programmers Get Their Just Reward |date=1997-05-08 |first=Janelle |last=Brown |access-date=2015-03-10}}</ref> The role of the ENIAC programmers is treated in a 2010 documentary film titled ''Top Secret Rosies: The Female "Computers" of WWII'' by LeAnn Erickson.<ref name="secret">{{cite news |last=Gumbrecht |first=Jamie |title=Rediscovering WWII's female 'computers' |date=February 2011 |publisher=CNN |url=http://edition.cnn.com/2011/TECH/innovation/02/08/women.rosies.math/# |access-date=2011-02-15}}</ref> A 2014 documentary short, ''The Computers'' by Kate McMahon, tells of the story of the six programmers; this was the result of 20 years' research by Kathryn Kleiman and her team as part of the ENIAC Programmers Project.<ref name="siff">{{cite web |title=Festival 2014: The Computers |url=http://www.siff.net/festival-2014/computers |website=SIFF |access-date=2015-03-12 |archive-url=https://web.archive.org/web/20140810131728/http://www.siff.net/festival-2014/computers |archive-date=2014-08-10 |url-status=dead}}</ref><ref>{{cite web |title=ENIAC Programmers Project |url=http://eniacprogrammers.org/ |website=ENIAC Programmers Project |access-date=2021-11-25}}</ref> In 2022 Grand Central Publishing released ''Proving Ground'' by Kathy Kleiman, a hardcover biography about the six ENIAC programmers and their efforts to translate block diagrams and electronic schematics of the ENIAC, then under construction, into programs that would be loaded into and run on ENIAC once it was available for use.<ref>{{cite book |last1=Kleiman |first1=Kathy |title=Proving Ground: The Untold Story of the Six Women Who Programmed the World's First Modern Computer |date=July 2022 |publisher=Grand Central Publishing |isbn=978-1-5387-1828-5}}</ref>

In 2011, in honor of the 65th anniversary of the ENIAC's unveiling, the city of Philadelphia declared February 15 as ENIAC Day.<ref>{{cite web |url=http://legislation.phila.gov/attachments/11036.pdf |title=Resolution No. 110062: Declaring February 15 as "Electronic Numerical Integrator And Computer (ENIAC) Day" in Philadelphia and honoring the University of Pennsylvania School of Engineering and Applied Sciences. |date=2011-02-10 |access-date=2014-08-13}}</ref><ref>{{cite web |date=January 28, 2011 |title=Philly Post: Trending: Philly Vs. Iowa for the Soul of the Computer |url=http://www.phillymag.com/articles/philly-post-trending-philly-vs-iowa-for-the-soul-of-the-computer/ |accessdate=February 12, 2014 |archive-date=February 19, 2014 |archive-url=https://web.archive.org/web/20140219035354/http://www.phillymag.com/articles/philly-post-trending-philly-vs-iowa-for-the-soul-of-the-computer/ |url-status=dead }}</ref><ref>{{cite web |date=February 10, 2011 |title=ENIAC Day to celebrate dedication of Penn's historic computer |url=http://www.upenn.edu/pennnews/current/node/4171 |url-status=dead |archiveurl=https://web.archive.org/web/20140222152027/http://www.upenn.edu/pennnews/current/node/4171 |archivedate=February 22, 2014 |accessdate=February 14, 2014}}</ref>

The ENIAC celebrated its 70th anniversary on February 15, 2016.<ref>{{Cite news |url=http://www.phillyvoice.com/70-years-ago-six-philly-women-eniac-digital-computer-programmers/ |title=70 years ago, six Philly women became the world's first digital computer programmers |last=Kim |first=Meeri |date=2016-02-11 |access-date=2016-10-17 |via=www.phillyvoice.com}}</ref>

==See also==
* [[History of computing]]
* [[History of computing hardware]]
* Women in computing
* [[Engineering:List of vacuum-tube computers|List of vacuum-tube computers]]
* [[Engineering:Military computers|Military computers]]
* [[Company:Unisys|Unisys]]
* [[Biography:Arthur Burks|Arthur Burks]]
* [[Biography:Betty Holberton|Betty Holberton]]
* [[Biography:Frances Spence|Frances Bilas Spence]]
* [[Biography:John Mauchly|John Mauchly]]
* [[Biography:J. Presper Eckert|J. Presper Eckert]]
* Jean Jennings Bartik
* [[Biography:Kathleen Antonelli|Kathleen Antonelli (Kay McNulty)]]
* [[Biography:Marlyn Meltzer|Marlyn Meltzer]]
* Ruth Lichterman Teitelbaum

==Notes==
{{reflist|group=note}}
{{Reflist}}

==References==
{{Refbegin|}}
* {{cite journal |last=Burks |first=Arthur |title=Electronic Computing Circuits of the ENIAC |date=1947 |journal=Proceedings of the I.R.E. |volume=35 |issue=8 |pages=756–767 |doi=10.1109/jrproc.1947.234265}}
* {{cite journal |last1=Burks |first1=Arthur |title=The ENIAC: The First General-Purpose Electronic Computer |date=1981 |last2=Burks |first2=Alice R. |author-link2=Alice Burks |journal=Annals of the History of Computing |volume=3 |issue=4 |pages=310–389 |doi=10.1109/mahc.1981.10043 |s2cid=14205498}}
* {{cite journal |last1=Clippinger |first1=R. F. |title=A Logical Coding System Applied to the ENIAC |journal=Ballistic Research Laboratories Report |date=29 September 1948 |issue=673 |url=http://ftp.arl.mil/~mike/comphist/48eniac-coding/ |access-date=2010-01-27 |url-status=dead |archive-url=https://web.archive.org/web/20100103050402/http://ftp.arl.mil/~mike/comphist/48eniac-coding/ |archive-date=3 January 2010}} ([https://apps.dtic.mil/sti/citations/ADB205179 original source])
* {{cite book |editor-last=Copeland |editor-first=B. Jack |date=2006 |title=Colossus: The Secrets of Bletchley Park's Codebreaking Computers |place=Oxford |publisher=[[Organization:Oxford University Press|Oxford University Press]] |isbn=9780192840554}}
* {{cite book |chapter-url=https://books.google.com/books?id=vIHRnE-Ie2kC&pg=PA167PG |title=Logic and Theory of Algorithms: 4th Conference on Computability in Europe, CiE 2008 Athens, Greece, June 15-20, 2008, Proceedings |last1=De Mol |first1=Liesbeth |last2=Bullynck |first2=Maarten |date=2008 |publisher=Springer Science & Business Media |isbn=9783540694052 |editor-last=Beckmann |editor-first=Arnold |pages=158–167 |chapter=A Week-End Off: The First Extensive Number-Theoretical Computation on ENIAC |editor-last2=Dimitracopoulos |editor-first2=Costas |editor-last3=Löwe |editor-first3=Benedikt}}
* [[Biography:J. Presper Eckert|Eckert, J. Presper]], ''The ENIAC'' (in Nicholas Metropolis, [[Biography:Jack Howlett|J. Howlett]], Gian-Carlo Rota, (editors), ''A History of Computing in the Twentieth Century'', Academic Press, New York, 1980, pp.&nbsp;525–540)
* [[Biography:J. Presper Eckert|Eckert, J. Presper]] and [[Biography:John Mauchly|John Mauchly]], 1946, ''Outline of plans for development of electronic computers'', 6 pages. (The founding document in the electronic computer industry.)
* Fritz, W. Barkley, ''The Women of ENIAC'' (in ''IEEE Annals of the History of Computing'', Vol. 18, 1996, pp.&nbsp;13–28)
* {{cite journal |last1=Goldstine |first1=Adele |title=A Report on the ENIAC |journal=FTP.arl.mil |date=1946 |volume=1 |issue=1 |url=http://ftp.arl.mil/~mike/comphist/46eniac-report/chap1.html |at=Chapter 1 -- Introduction: 1.1.2. The Units of the ENIAC}} [https://apps.dtic.mil/sti/citations/ADA622372 original source]
* {{Cite journal |last1=Goldstine |first1=Herman H. |last2=Goldstine |first2=Adele K. |date=1946 |title=The electronic numerical integrator and computer (ENIAC) |journal=Mathematics of Computation |volume=2 |issue=15 |pages=97–110 |doi=10.1090/S0025-5718-1946-0018977-0 |issn=0025-5718|doi-access=free}} (also reprinted in ''The Origins of Digital Computers: Selected Papers'', Springer-Verlag, New York, 1982, pp.&nbsp;359–373)
* {{cite book |last1=Goldstine |first1=Adele K. |title=Central Control for ENIAC |date=10 July 1947 |page=1 |url=http://eniacinaction.com/the-articles/2-engineering-the-miracle-of-the-eniac-implementing-the-modern-code-paradigm/ |quote=Unlike the later 60- and 100-order codes this one [51 order code] required no additions to ENIAC's original hardware. It would have worked more slowly and offered a more restricted range of instructions but the basic structure of accumulators and instructions changed only slightly.}}
* {{cite book |url=https://books.google.com/books?id=3FvELn2KiUYC |title=The Computer: from Pascal to von Neumann |last=Goldstine |first=Herman H. |year=1993 |location=Princeton, NJ |publisher=Princeton University Press |orig-date=1972 |isbn=9780691023670 |}}
* {{Cite journal |url=http://eniacinaction.com/the-articles/2-engineering-the-miracle-of-the-eniac-implementing-the-modern-code-paradigm/ |title=Engineering 'The Miracle of the ENIAC': Implementing the Modern Code Paradigm |last1=Haigh |first1=Thomas |last2=Priestley |first2=Mark |last3=Rope |first3=Crispin |date=April–June 2014b |volume=36 |issue=2 |pages=41–59 |journal=IEEE Annals of the History of Computing |access-date=2018-11-13 |doi=10.1109/MAHC.2014.15 |s2cid=24359462}}
* {{cite book |title=ENIAC in Action: Making and Remaking the Modern Computer |last1=Haigh |first1=Thomas |last2=Priestley |first2=Mark |last3=Rope |first3=Crispin |publisher=MIT Press |date=2016 |isbn=978-0-262-53517-5 |url=https://books.google.com/books?id=_oqBCwAAQBAJ}}
* {{cite journal |last=Light |first=Jennifer S. |date=1999 |title=When Computers Were Women |journal=Technology and Culture |volume=40 |issue=3 |pages=455–483  |doi=10.1353/tech.1999.0128 |jstor=25147356 |s2cid=108407884 |issn=0040-165X |url=http://pcfly.info/doc/Computers/18.pdf |archive-url=https://web.archive.org/web/20151122025204/http://pcfly.info/doc/Computers/18.pdf |archive-date=2015-11-22 |access-date=2015-03-09}}
* [[Biography:John Mauchly|Mauchly, John]], ''The ENIAC'' (in Metropolis, Nicholas, [[Biography:Jack Howlett|Howlett, Jack]]; Rota, Gian-Carlo. 1980, ''A History of Computing in the Twentieth Century'', [[Company:Academic Press|Academic Press]], New York, {{ISBN|0-12-491650-3}}, pp.&nbsp;541–550, "Original versions of these papers were presented at the International Research Conference on the History of Computing, held at the Los Alamos Scientific Laboratory, 10–15 June 1976.")
* {{cite book |last=McCartney |first=Scott |date=1999 |title=ENIAC: The Triumphs and Tragedies of the World's First Computer |publisher=Walker & Co. |isbn=978-0-8027-1348-3 |url=https://archive.org/details/eniac00scot}}
* Rojas, Raúl; Hashagen, Ulf, editors. ''The First Computers: History and Architectures'', 2000, MIT Press, {{ISBN|0-262-18197-5}}
* {{cite journal |last1=Stuart |first1=Brian L. |title=Simulating the ENIAC [Scanning Our Past] |journal=Proceedings of the IEEE |date=2018 |volume=106 |issue=4 |pages=761–772 |doi=10.1109/JPROC.2018.2813678}}
* {{cite journal |last1=Stuart |first1=Brian L. |title=Programming the ENIAC [Scanning Our Past] |journal=Proceedings of the IEEE |date=2018 |volume=106 |issue=9 |pages=1760–1770 |doi=10.1109/JPROC.2018.2843998|doi-access=free}}
* {{cite journal |last1=Stuart |first1=Brian L. |title=Debugging the ENIAC [Scanning Our Past] |journal=Proceedings of the IEEE |date=2018 |volume=106 |issue=12 |pages=2331–2345 |doi=10.1109/JPROC.2018.2878986|doi-access=free}}
{{Refend}}

==Further reading==
{{Refbegin}}
* Berkeley, Edmund. ''GIANT BRAINS or machines that think''. John Wiley & Sons, inc., 1949. Chapter 7 ''Speed – 5000 Additions a Second: Moore School's ENIAC (Electronic Numerical Integrator And Computer)''
* {{cite book |ref=none |title=Turing's Cathedral: The Origins of the Digital Universe |url=https://archive.org/details/turingscathedral0000dyso |url-access=registration |last=Dyson |first=George |publisher=Pantheon Books |date=2012 |isbn=978-0-375-42277-5 |location=New York |}}
* {{Cite news |ref=none |last=Gumbrecht |first=Jamie |title=Rediscovering WWII's 'computers' |publisher=CNN.com |date=8 February 2011 |url=http://www.cnn.com/2011/TECH/innovation/02/08/women.rosies.math/index.html?hpt=C2 |access-date=9 February 2011}}
* Hally, Mike. ''Electronic Brains: Stories from the Dawn of the Computer Age'', [[Biography:Joseph Henry|Joseph Henry]] Press, 2005. {{ISBN|0-309-09630-8}}
* {{cite book |ref=none |last=Lukoff |first=Herman |title=From Dits to Bits: A personal history of the electronic computer |date=1979 |publisher=Robotics Press |location=Portland, OR |isbn=978-0-89661-002-6 |lccn=79-90567}}
* Tompkins, C. B.; Wakelin, J. H.; ''High-Speed Computing Devices'', McGraw-Hill, 1950.
* {{cite book |ref=none |title=From ENIAC to UNIVAC: An Appraisal of the Eckert–Mauchly Computers |last=Stern |first=Nancy |publisher=Digital Press |date=1981 |isbn=978-0-932376-14-5}}
* {{cite web |ref=none |title=ENIAC Operating Manual |url=http://www.bitsavers.org/pdf/univOfPennsylvania/eniac/ENIAC_Operating_Manual_Jun46.pdf |website=www.bitsavers.org}}
{{Refend}}

==External links==
{{Commons}}
* [http://zuse-z1.zib.de/simulations/eniac/ ENIAC simulation]
* [http://www.historicsimulations.com/eniac.html Another ENIAC simulation]
* [http://cs.drexel.edu/~bls96/eniac/eniac.html Pulse-level ENIAC simulator]
* [https://www.thingiverse.com/thing:4164825 3D printable model of the ENIAC]
* [http://www.computerworld.com/article/2561813/computer-hardware/q-a--a-lost-interview-with-eniac-co-inventor-j--presper-eckert.html Q&A: A lost interview with ENIAC co-inventor J. Presper Eckert]
* [http://americanhistory.si.edu/comphist/eckert.htm Interview with Eckert] Transcript of a video interview with Eckert by David Allison for the National Museum of American History, Smithsonian Institution on February 2, 1988. An in-depth, technical discussion on ENIAC, including the thought process behind the design.
* [http://purl.umn.edu/107275 Oral history interview with J. Presper Eckert], Charles Babbage Institute, University of Minnesota. Eckert, a co-inventor of ENIAC, discusses its development at the University of Pennsylvania's Moore School of Electrical Engineering; describes difficulties in securing patent rights for ENIAC and the problems posed by the circulation of John von Neumann's 1945 First Draft of the Report on EDVAC, which placed the ENIAC inventions in the public domain. Interview by Nancy Stern, 28 October 1977.
* [http://purl.umn.edu/107216 Oral history interview with Carl Chambers], Charles Babbage Institute, University of Minnesota. Chambers discusses the initiation and progress of the ENIAC project at the University of Pennsylvania Moore School of Electrical Engineering (1941–46). Oral history interview by Nancy B. Stern, 30 November 1977.
* [http://purl.umn.edu/107688 Oral history interview with Irven A. Travis], Charles Babbage Institute, University of Minnesota. Travis describes the ENIAC project at the University of Pennsylvania (1941–46), the technical and leadership abilities of chief engineer Eckert, the working relations between John Mauchly and Eckert, the disputes over patent rights, and their resignation from the university. Oral history interview by Nancy B. Stern, 21 October 1977.
* [http://purl.umn.edu/107704 Oral history interview with S. Reid Warren], Charles Babbage Institute, University of Minnesota. Warren served as supervisor of the EDVAC project; central to his discussion are J. Presper Eckert and John Mauchly and their disagreements with administrators over patent rights; discusses John von Neumann's 1945 draft report on the EDVAC, and its lack of proper acknowledgment of all the EDVAC contributors.
* [https://web.archive.org/web/20090123114642/http://www.eniacprogrammers.org/index.shtml ENIAC Programmers Project]
* [https://www.wired.com/news/culture/0,1284,3711,00.html The women of ENIAC]
* [http://www.columbia.edu/acis/history/eniac.html Programming ENIAC]
* [https://web.archive.org/web/20041014180109/http://www4.wittenberg.edu/academics/mathcomp/bjsdir/ENIACSquareRoot.htm How ENIAC took a Square Root]
* [https://web.archive.org/web/20060909174756/http://ftp.arl.army.mil/~mike/comphist/48eniac-coding/.. Mike Muuss: Collected ENIAC documents]
* [https://web.archive.org/web/20040803150905/http://ftp.arl.mil/~mike/comphist/61ordnance/chap2.html ENIAC] chapter in Karl Kempf, ''Electronic Computers Within The Ordnance Corps'', November 1961
* [https://web.archive.org/web/20110814181522/http://ftp.arl.mil/~mike/comphist/eniac-story.html The ENIAC Story], Martin H. Weik, Ordnance Ballistic Research Laboratories, 1961
* [http://www.seas.upenn.edu/~museum/index.html ENIAC museum] at the University of Pennsylvania
* [http://ed-thelen.org/comp-hist/BRL-e-h.html#ENIAC ENIAC specifications] from Ballistic Research Laboratories Report No. 971 December 1955, (A Survey of Domestic Electronic Digital Computing Systems)
* [http://news.cnet.com/2009-1006_3-6037980.html A Computer Is Born], Michael Kanellos, 60th anniversary news story, ''CNet'', February 13, 2006
* [https://www.youtube.com/watch?v=bGk9W65vXNA 1946 film restored, Computer History Archives Project]


[[Category:Military computers]]
[[Category:Artillery components]]

{{Sourceattribution|ENIAC}}