Coordinates: 39°57′08″N 75°11′26″W / 39.9523°N 75.1906°W / 39.9523; -75.1906
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Four ENIAC panels and one of its three function tables at the School of Engineering and Applied Science at the University of Pennsylvania
LocationUniversity of Pennsylvania Department of Computer and Information Science, 3330 Walnut Street, Philadelphia, Pennsylvania, U.S.
Coordinates39°57′08″N 75°11′26″W / 39.9523°N 75.1906°W / 39.9523; -75.1906
PHMC dedicatedThursday, June 15, 2000
Glenn A. Beck (background) and Betty Snyder (foreground) program ENIAC in BRL building 328. (U.S. Army photo, c. 1947–1955)

ENIAC (/ˈɛniæk/; Electronic Numerical Integrator and Computer)[1][2] was the first programmable, electronic, general-purpose digital computer, completed in 1945.[3][4] Other computers had some of these features, but ENIAC was the first to have them all. It was Turing-complete and able to solve "a large class of numerical problems" through reprogramming.[5][6]

ENIAC was designed by John Mauchly and J. Presper Eckert to calculate artillery firing tables for the United States Army's Ballistic Research Laboratory (which later became a part of the Army Research Laboratory).[7][8] However, its first program was a study of the feasibility of the thermonuclear weapon.[9][10]

ENIAC was completed in 1945 and first put to work for practical purposes on December 10, 1945.[11]

ENIAC was formally dedicated at the University of Pennsylvania on February 15, 1946, having cost $487,000 (equivalent to $6,900,000 in 2023), and called a "Giant Brain" by the press.[12] It had a speed on the order of one thousand times faster than that of electro-mechanical machines.[13]

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[edit]

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, equivalent to $6,900,000 in 2023.[14] The construction contract was signed on June 5, 1943; work on the computer began in secret at the University of Pennsylvania's Moore School of Electrical Engineering[15] 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.[16]

ENIAC was designed by Ursinus College physics professor John Mauchly and J. Presper Eckert of the University of Pennsylvania, U.S.[17] 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), Arthur Burks (multiplier), Harry Huskey (reader/printer) and Jack Davis (accumulators).[18] Significant development work was undertaken by the female mathematicians who handled the bulk of the ENIAC programming: Jean Jennings, Marlyn Wescoff, Ruth Lichterman, Betty Snyder, Frances Bilas, and Kay McNulty.[19] In 1946, the researchers resigned from the University of Pennsylvania and formed the 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 number in memory. Numbers were passed between these units across several general-purpose 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.


By the end of its operation in 1956, ENIAC contained 18,000 vacuum tubes, 7,200 crystal diodes, 1,500 relays, 70,000 resistors, 10,000 capacitors, and approximately 5,000,000 hand-soldered joints. It weighed more than 30 short tons (27 t), was roughly 8 ft (2 m) tall, 3 ft (1 m) deep, and 100 ft (30 m) long, occupied 300 sq ft (28 m2) and consumed 150 kW of electricity.[20][21] 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 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.[22] In 1953, a 100-word magnetic-core memory built by the Burroughs Corporation was added to ENIAC.[23]

ENIAC used ten-position ring counters to store digits; each digit required 36 vacuum tubes, 10 of which were the dual triodes making up the 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 adding machine.[24]

ENIAC had 20 ten-digit signed 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.[25][26]

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)[27]

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 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.[28][29]

Operation times[edit]

The references by Rojas and Hashagen (or Wilkes)[17] give more details about the times for operations, which differ somewhat from those stated above.

The basic machine cycle was 200 microseconds (20 cycles of the 100 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[17] 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,[30] compared to modern supercomputers' petascale and exascale computing power.


ENIAC used common octal-base radio tubes of the day; the decimal accumulators were made of 6SN7 flip-flops, while 6L7s, 6SJ7s, 6SA7s and 6AC7s were used in logic functions.[31] Numerous 6L6s and 6V6s 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."[32] In 1954, the longest continuous period of operation without a failure was 116 hours—close to five days.


ENIAC could be programmed to perform complex sequences of operations, including loops, branches, and subroutines. However, instead of the stored-program computers that exist today, ENIAC was just a large collection of arithmetic machines, which originally had programs set up into the machine[33] by a combination of plugboard wiring and three portable function tables (containing 1,200 ten-way switches each).[34] 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.[35] 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.[36][37][38]

ENIAC's six primary programmers, Kay McNulty, Betty Jennings, Betty Snyder, Marlyn Wescoff, Fran Bilas and Ruth Lichterman, not only determined how to input ENIAC programs, but also developed an understanding of ENIAC's inner workings.[39][40] The programmers were often able to narrow bugs down to an individual failed tube which could be pointed to for replacement by a technician.[41]


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)

During 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 "computers"[19] and six of them were chosen to be the programmers of ENIAC. Betty Holberton, Kay McNulty, Marlyn Wescoff, Ruth Lichterman, Betty Jean Jennings, and Fran Bilas, programmed the ENIAC to perform calculations for ballistics trajectories electronically for the Army's Ballistic Research Laboratory.[42] 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.[42]

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.[43] However, some of the women did not receive recognition for their work on the ENIAC in their entire lifetimes.[19] After the war ended, the women continued to work on the ENIAC. Their expertise made their positions difficult to replace with returning soldiers.[44]

These early programmers were drawn from a group of about two hundred women employed as 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.[19] This was one of the few technical job categories available to women at that time.[45] Betty Holberton (née Snyder) continued on to help write the first generative programming system (SORT/MERGE) and help design the first commercial electronic computers, the UNIVAC and the BINAC, alongside Jean Jennings.[46] McNulty developed the use of subroutines in order to help increase ENIAC's computational capability.[47]

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.[19] Under Herman and Adele Goldstine's direction, the computers studied ENIAC's blueprints and physical structure to determine how to manipulate its switches and cables, as programming languages 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,[19] McNulty, Jennings, Snyder, Wescoff, Bilas, and Lichterman have since been recognized for their contributions to computing.[48][49][50] Three of the current (2020) Army supercomputers Jean, Kay, and Betty are named after Jean Bartik (Betty Jennings), Kay McNulty, and Betty Snyder respectively.[51]

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.[19] 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.[19] 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".[19]

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 Gloria Ruth Gordon.[52] Adele Goldstine wrote the original technical description of the ENIAC.[53]

Programming languages[edit]

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

Year Name Chief developers
1943–46 ENIAC coding system John von Neumann, John Mauchly, J. Presper Eckert, Herman Goldstine after Alan Turing.
1946 ENIAC Short Code Richard Clippinger, John von Neumann after Alan Turing
1946 Von Neumann and Goldstine graphing system (Notation) John von Neumann and Herman Goldstine
1947 ARC Assembly Kathleen Booth[54][55]
1948 Curry notation system Haskell Curry

Role in the hydrogen bomb[edit]

Although the Ballistic Research Laboratory was the sponsor of ENIAC, one year into this three-year project John von Neumann, a mathematician working on the hydrogen bomb at Los Alamos National Laboratory, became aware of the ENIAC.[56] In December 1945, the ENIAC was used to calculate thermonuclear reactions using equations. The data was used to support research on building a hydrogen bomb.[57][58]

Role in development of the Monte Carlo methods[edit]

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. John von Neumann and Stanislaw Ulam realized the speed of ENIAC would allow these calculations to be done much more quickly.[59] The success of this project showed the value of Monte Carlo methods in science.[60]

Later developments[edit]

A press conference was held on February 1, 1946,[19] and the completed machine was announced to the public the evening of February 14, 1946,[61] 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.[19] The machine was formally dedicated the next day[62] 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.[63]

The original contract amount was $61,700; the final cost was almost $500,000 (approximately equivalent to $9,000,000 in 2023). 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 p.m. on October 2, 1955, when it was retired in favor of the more efficient EDVAC and ORDVAC computers.[2]

Role in the development of the EDVAC[edit]

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",[64] the Pentagon invited "the top people in electronics and mathematics from the United States and Great Britain"[64] 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.[64] Half of these lectures were given by the inventors of ENIAC.[65]

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) 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 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.[66]


A number of improvements were made to ENIAC after 1947, including a primitive read-only stored programming mechanism using the function tables as program ROM,[66][67][68][69][70][71] after which programming was done by setting the switches.[72] 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,[73] and it was included in the ENIAC patent.[74] Clippinger consulted with von Neumann on what instruction set to implement.[66][75][76] 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,[77] which made possible programming through the reader from standard IBM cards.[78][79] The "first production run" of the new coding techniques on the Monte Carlo problem followed in April.[77][80] 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.[81]

The programming of the stored program for ENIAC was done by Betty Jennings, Clippinger, Adele Goldstine and others.[82][83][67][66] It was first demonstrated as a stored-program computer in April 1948,[84] running a program by 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[76][66] 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 core memory was added to the system, using binary-coded decimal, 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.[66]

Comparison with other early computers[edit]

Pennsylvania state historical marker on the University of Pennsylvania's campus in Philadelphia

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

ENIAC was, like the IBM 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 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 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.[85] In June 1948, the Manchester Baby ran its first program and earned the distinction of first electronic stored-program computer.[86][87][88] 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[edit]

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 Iowa State University was stopped in 1942 after John Atanasoff was called to Washington, D.C., to do physics research for the U.S. Navy, and it was subsequently dismantled.[89] 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 GCHQ until the 1960s.[90][91] 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.[47]


For a variety of reasons – including Mauchly's June 1941 examination of the Atanasoff–Berry computer (ABC), prototyped in 1939 by John Atanasoff and Clifford Berry – U.S. patent 3,120,606 for ENIAC, applied for in 1947 and granted in 1964, was voided by the 1973[92] 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 public domain.

Main parts[edit]

The bottoms of three accumulators at Fort Sill, Oklahoma, US
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.[93]

Parts on display[edit]

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).[93]
  • 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)[93] in the National Museum of American History in Washington, D.C.[19] (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).[93]
  • The University of Michigan in Ann Arbor has four panels (two accumulators, High-speed Multiplier panel 3, and Master Programmer panel 2),[93] salvaged by 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.[94] There are accumulators #7, #8, #11, and #17;[95] panel #1 and #2 that connected to function table #1,[93] 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)[93] (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.[96][97]


ENIAC was named an IEEE Milestone in 1987.[98]

ENIAC on a Chip, University of Pennsylvania (1995) - Computer History Museum

In 1996, in honor of the ENIAC's 50th anniversary, The University of Pennsylvania sponsored a project named "ENIAC-on-a-Chip", where a very small silicon computer chip measuring 7.44 mm by 5.29 mm was built with the same functionality as ENIAC. Although this 20 MHz chip was many times faster than ENIAC, it had but a fraction of the speed of its contemporary microprocessors in the late 1990s.[99][100][101]

In 1997, the six women who did most of the programming of ENIAC were inducted into the Technology International Hall of Fame.[48][102] 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.[49] 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.[50][103] 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.[104]

In 2011, in honor of the 65th anniversary of the ENIAC's unveiling, the city of Philadelphia declared February 15 as ENIAC Day.[105][106][107]

The ENIAC celebrated its 70th anniversary on February 15, 2016.[108]

See also[edit]


  1. ^ 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.
  2. ^ a b Weik, Martin H. "The ENIAC Story". Ordnance (January–February 1961). Washington, DC: American Ordnance Association. Archived from the original on August 14, 2011. Retrieved March 29, 2015.
  3. ^ "3.2 First Generation Electronic Computers (1937-1953)". www.phy.ornl.gov. Archived from the original on March 8, 2012.
  4. ^ "ENIAC on Trial – 1. Public Use". www.ushistory.org. Search for 1945. Archived from the original on February 9, 2019. Retrieved May 16, 2018. 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.
  5. ^ Goldstine & Goldstine 1946, p. 97
  6. ^ Shurkin, Joel (1996). Engines of the mind: the evolution of the computer from mainframes to microprocessors. New York: Norton. ISBN 978-0-393-31471-7.
  7. ^ Moye, William T. (January 1996). "ENIAC: The Army-Sponsored Revolution". US Army Research Laboratory. Archived from the original on May 21, 2017. Retrieved March 29, 2015.
  8. ^ Goldstine 1993, p. 214.
  9. ^ Rhodes 1995, p. 251, chapter 13: 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.
  10. ^ 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."
  11. ^ *"ENIAC on Trial – 1. Public Use". www.ushistory.org. Search for 1945. Retrieved May 16, 2018. 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.
  12. ^ "'ENIAC': Creating a Giant Brain, and Not Getting Credit". The New York Times.
  13. ^ "ENIAC USA 1946". The History of Computing Project. History of Computing Foundation. March 13, 2013. Archived from the original on January 4, 2021.
  14. ^ Dalakov, Georgi. "ENIAC". History of Computers. Georgi Dalakov. Retrieved May 23, 2016.
  15. ^ Goldstine & Goldstine 1946
  16. ^ Gayle Ronan Sims (June 22, 2004). "Herman Heine Goldstine". The Philadelphia Inquirer. Archived from the original on November 30, 2015. Retrieved April 15, 2017 – via www.princeton.edu.
  17. ^ a b c Wilkes, M. V. (1956). Automatic Digital Computers. New York: John Wiley & Sons. QA76.W5 1956.
  18. ^ "ENIAC on Trial". USHistory.org. Independence Hall Association. Archived from the original on August 12, 2019. Retrieved November 9, 2020.
  19. ^ a b c d e f g h i j k l Light 1999.
  20. ^ "ENIAC". The Free Dictionary. Retrieved March 29, 2015.
  21. ^ Weik, Martin H. (December 1955). Ballistic Research Laboratories Report No. 971: A Survey of Domestic Electronic Digital Computing Systems. Aberdeen Proving Ground, MD: United States Department of Commerce Office of Technical Services. p. 41. Retrieved March 29, 2015.
  22. ^ "ENIAC in Action: What it Was and How it Worked". ENIAC: Celebrating Penn Engineering History. University of Pennsylvania. Retrieved May 17, 2016.
  23. ^ Martin, Jason (December 17, 1998). "Past and Future Developments in Memory Design". Past and Future Developments in Memory Design. University of Maryland. Retrieved May 17, 2016.
  24. ^ Peddie, Jon (June 13, 2013). The History of Visual Magic in Computers: How Beautiful Images are Made in CAD, 3D, VR and AR. Springer Science & Business Media. ISBN 978-1-4471-4932-3.
  25. ^ Goldstine & Goldstine 1946.
  26. ^ Igarashi, Yoshihide; Altman, Tom; Funada, Mariko; Kamiyama, Barbara (May 27, 2014). Computing: A Historical and Technical Perspective. CRC Press. ISBN 978-1-4822-2741-3.
  27. ^ The original photo can be seen in the article: Rose, Allen (April 1946). "Lightning Strikes Mathematics". Popular Science: 83–86. Retrieved March 29, 2015.
  28. ^ Clippinger 1948, Section I: General Description of the ENIAC – The Function Tables.
  29. ^ Goldstine 1946.
  30. ^ "The incredible evolution of supercomputers' powers, from 1946 to today". Popular Science. March 18, 2019. Retrieved February 8, 2022.
  31. ^ Burks 1947, pp. 756–767
  32. ^ Randall, Alexander 5th (February 14, 2006). "A lost interview with ENIAC co-inventor J. Presper Eckert". Computer World. Retrieved March 29, 2015.
  33. ^ Grier, David (July–September 2004). "From the Editor's Desk". IEEE Annals of the History of Computing. 26 (3): 2–3. doi:10.1109/MAHC.2004.9. S2CID 7822223.
  34. ^ Cruz, Frank (November 9, 2013). "Programming the ENIAC". Programming the ENIAC. Columbia University. Retrieved May 16, 2016.
  35. ^ Alt, Franz (July 1972). "Archaeology of computers: reminiscences, 1945-1947". Communications of the ACM. 15 (7): 693–694. doi:10.1145/361454.361528. S2CID 28565286.
  36. ^ Schapranow, Matthieu-P. (June 1, 2006). "ENIAC tutorial - the modulo function". Archived from the original on January 7, 2014. Retrieved March 4, 2017.
  37. ^ Description of Lehmer's program computing the exponent of modulo 2 prime
  38. ^ De Mol & Bullynck 2008
  39. ^ "ENIAC Programmers Project". eniacprogrammers.org. Retrieved March 29, 2015.
  40. ^ Donaldson James, Susan (December 4, 2007). "First Computer Programmers Inspire Documentary". ABC News. Retrieved March 29, 2015.
  41. ^ Fritz, W. Barkley (1996). "The Women of ENIAC" (PDF). IEEE Annals of the History of Computing. 18 (3): 13–28. doi:10.1109/85.511940. Archived from the original (PDF) on March 4, 2016. Retrieved April 12, 2015.
  42. ^ a b McCabe, Seabright (June 3, 2019). "The Programming Pioneers of ENIAC". All Together. No. Spring 2019. Society of Women Engineers. Archived from the original on December 25, 2023. Retrieved July 8, 2020.
  43. ^ "Meet the 'Refrigerator Ladies' Who Programmed the ENIAC". Mental Floss. October 13, 2013. Retrieved June 16, 2016.
  44. ^ "ENIAC Programmers: A History of Women in Computing". Atomic Spin. July 31, 2016.
  45. ^ Grier, David (2007). When Computers Were Human. Princeton University Press. ISBN 9781400849369. Retrieved November 24, 2016.
  46. ^ Beyer, Kurt (2012). Grace Hopper and the Invention of the Information Age. London, Cambridge: MIT Press. p. 198. ISBN 9780262517263.
  47. ^ a b Isaacson, Walter (September 18, 2014). "Walter Isaacson on the Women of ENIAC". Fortune. Archived from the original on December 12, 2018. Retrieved December 14, 2018.
  48. ^ a b "Invisible Computers: The Untold Story of the ENIAC Programmers". Witi.com. Retrieved March 10, 2015.
  49. ^ a b Gumbrecht, Jamie (February 2011). "Rediscovering WWII's female 'computers'". CNN. Retrieved February 15, 2011.
  50. ^ a b "Festival 2014: The Computers". SIFF. Archived from the original on August 10, 2014. Retrieved March 12, 2015.
  51. ^ "Army researchers acquire two new supercomputers". U.S. Army DEVCOM Army Research Laboratory Public Affairs. December 28, 2020. Retrieved March 1, 2021.
  52. ^ Sullivan, Patricia (July 26, 2009). "Gloria Gordon Bolotsky, 87; Programmer Worked on Historic ENIAC Computer". The Washington Post. Retrieved August 19, 2015.
  53. ^ "ARL Computing History | U.S. Army Research Laboratory". Arl.army.mil. Retrieved June 29, 2019.
  54. ^ Booth, Kathleen. "Machine Language for Automatic Relay Computer". Birkbeck College Computation Laboratory. University of London.
  55. ^ 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
  56. ^ Goldstine 1993, p. 182
  57. ^ Yost, Jeffrey R. (2017). Making IT Work: A History of the Computer Services Industry. MIT Press. p. 19. ISBN 9780262036726.
  58. ^ Rhodes 1995, chapter 2
  59. ^ Mazhdrakov, Metodi; Benov, Dobriyan; Valkanov, Nikolai (2018). The Monte Carlo Method. Engineering Applications. ACMO Academic Press. p. 250. ISBN 978-619-90684-3-4.
  60. ^ Kean, Sam (2010). The Disappearing Spoon. New York: Little, Brown and Company. pp. 109–111. ISBN 978-0-316-05163-7.
  61. ^ Kennedy, T. R. Jr. (February 15, 1946). "Electronic Computer Flashes Answers". New York Times. Archived from the original on July 10, 2015. Retrieved March 29, 2015.
  62. ^ Honeywell, Inc. v. Sperry Rand Corp., 180 U.S.P.Q. (BNA) 673, p. 20, finding 1.1.3 (U.S. District Court for the District of Minnesota, Fourth Division 1973) ("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 ...").
  63. ^ Evans, Claire L. (March 6, 2018). Broad Band: The Untold Story of the Women Who Made the Internet. Penguin. p. 51. ISBN 9780735211766.
  64. ^ a b c McCartney 1999, p. 140
  65. ^ 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."
  66. ^ a b c d e f "Eniac". Epic Technology for Great Justice. Retrieved January 28, 2017.
  67. ^ a b Goldstine 1947.
  68. ^ Goldstine 1993, pp. 233–234, 270, search string: "eniac Adele 1947"
  69. ^ 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."
  70. ^ Clippinger 1948, Section IV: Summary of Orders
  71. ^ Haigh, Priestley & Rope 2014b, pp. 44–48
  72. ^ Pugh, Emerson W. (1995). "Notes to Pages 132-135". Building IBM: Shaping an Industry and Its Technology. MIT Press. p. 353. ISBN 9780262161473.
  73. ^ Haigh, Priestley & Rope 2014b, pp. 44–45.
  74. ^ Haigh, Priestley & Rope 2014b, p. 44.
  75. ^ Clippinger 1948, INTRODUCTION.
  76. ^ a b Goldstine 1993, 233-234, 270; search string: eniac Adele 1947.
  77. ^ a b Haigh, Priestley & Rope 2014b, pp. 47–48.
  78. ^ Clippinger 1948, Section VIII: Modified ENIAC.
  79. ^ Fritz, W. Barkley (1949). "Description and Use of the ENIAC Converter Code". Technical Note (141). Section 1. – Introduction, p. 1. 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.
  80. ^ Haigh, Thomas; Priestley, Mark; Rope, Crispin (July–September 2014c). "Los Alamos Bets On ENIAC: Nuclear Monte Carlo Simulations 1947-48". IEEE Annals of the History of Computing. 36 (3): 42–63. doi:10.1109/MAHC.2014.40. S2CID 17470931. Retrieved November 13, 2018.
  81. ^ Haigh, Priestley & Rope 2016, pp. 113–114.
  82. ^ Clippinger 1948, INTRODUCTION
  83. ^ Haigh, Priestley & Rope 2014b, p. 44
  84. ^ Haigh, Priestley & Rope 2016, p. 153.
  85. ^ See #Improvements
  86. ^ "Programming the ENIAC: an example of why computer history is hard | @CHM Blog". Computer History Museum. May 18, 2016.
  87. ^ Haigh, Thomas; Priestley, Mark; Rope, Crispin (January–March 2014a). "Reconsidering the Stored Program Concept". IEEE Annals of the History of Computing. 36 (1): 9–10. doi:10.1109/mahc.2013.56. S2CID 18827916.
  88. ^ Haigh, Priestley & Rope 2014b, pp. 48–54.
  89. ^ Copeland 2006, p. 106.
  90. ^ Copeland 2006, p. 2.
  91. ^ Ward, Mark (May 5, 2014), "How GCHQ built on a colossal secret", BBC News
  92. ^ "Atanasoff-Berry Computer Court Case". Retrieved September 1, 2022.
  93. ^ a b c d e f g Haigh, Priestley & Rope 2016, pp. 46, 264.
  94. ^ Meador, Mitch (October 29, 2014). "ENIAC: First Generation Of Computation Should Be A Big Attraction At Sill". The Lawton Constitution. Archived from the original on April 6, 2015. Retrieved April 8, 2015.
  95. ^ Haigh. et al. list accumulators 7, 8, 13, and 17, but 2018 photos show 7, 8, 11, and 17.[full citation needed]
  96. ^ "Meet the iPhone's 30-ton ancestor: Inside the project to rebuild one of the first computers". TechRepublic. November 23, 2016. Bringing the Eniac back to life.
  97. ^ "ENIAC – Life-size model of the first vacuum-tube computer". Germany: Heinz Nixdorf Museum. Archived from the original on November 5, 2016. Retrieved March 1, 2021.
  98. ^ "Milestones:Electronic Numerical Integrator and Computer, 1946". IEEE Global History Network. IEEE. Retrieved August 3, 2011.
  99. ^ "Looking Back At ENIAC: Commemorating A Half-Century Of Computers In The Reviewing System". The Scientist Magazine.
  100. ^ Van Der Spiegel, Jan (1996). "ENIAC-on-a-Chip". PENN PRINTOUT. Vol. 12, no. 4. The University of Pennsylvania. Archived from the original on October 11, 2012. Retrieved October 17, 2016.
  101. ^ Van Der Spiegel, Jan (May 9, 1995). "ENIAC-on-a-Chip". University of Pennsylvania. Retrieved September 4, 2009.
  102. ^ Brown, Janelle (May 8, 1997). "Wired: Women Proto-Programmers Get Their Just Reward". Retrieved March 10, 2015.
  103. ^ "ENIAC Programmers Project". ENIAC Programmers Project. Retrieved November 25, 2021.
  104. ^ Kleiman, Kathy (July 2022). Proving Ground: The Untold Story of the Six Women Who Programmed the World's First Modern Computer. Grand Central Publishing. ISBN 978-1-5387-1828-5.
  105. ^ "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" (PDF). February 10, 2011. Retrieved August 13, 2014.
  106. ^ "Philly Post: Trending: Philly Vs. Iowa for the Soul of the Computer". January 28, 2011. Archived from the original on February 19, 2014. Retrieved February 12, 2014.
  107. ^ "ENIAC Day to celebrate dedication of Penn's historic computer". February 10, 2011. Archived from the original on February 22, 2014. Retrieved February 14, 2014.
  108. ^ Kim, Meeri (February 11, 2016). "70 years ago, six Philly women became the world's first digital computer programmers". Retrieved October 17, 2016 – via www.phillyvoice.com.


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