42 Fun Facts About ENIAC

What does the acronym ENIAC stand for?

Electronic Numerical Integrator and Computer: it was designed to compute artillery firing tables for World War II, but it was finished too late to be used in the war.

Which computer built by ENIAC's inventors called Eisenhower's 1952 landslide on CBS television?

UNIVAC came within about 3 percent of Eisenhower's popular vote on election night, a publicity boost that made the new computer famous.

ENIAC read its numbers from punched cards using equipment made by which company?

IBM made ENIAC's card reader and card punch, and with so little internal memory, the machine relied on punched cards as its external storage.

What was the subject of ENIAC's first program?

The feasibility of the hydrogen bomb: though ENIAC was designed to compute artillery tables, its first real job, in December 1945, was a calculation for the H-bomb.

Where was ENIAC built and formally dedicated on February 15, 1946?

Penn's Moore School built ENIAC in secret for the Army, which kept the machine under wraps until months after World War II had ended.

What nickname did the press give ENIAC when it was unveiled?

Giant Brain was the press's name for ENIAC, yet the women who programmed it were not even introduced when the machine was unveiled in 1946.

How did ENIAC's engineers make its vacuum tubes last longer?

Running them at reduced power stretched tube life, which mattered because failing tubes could leave the machine out of action for long periods.

Eckert and Mauchly's BINAC computer was built for which aircraft maker, later prime contractor for the B-2 stealth bomber?

Northrop took delivery of the BINAC, but the machine never worked properly once it got there.

About how many vacuum tubes did ENIAC contain?

About 18,000: with so many, switching ENIAC off and on almost guaranteed a blown tube, so it was left running continuously.

How much electricity did ENIAC consume?

150 kW is the usual figure, though Army reports gave up to about 200 kW, and all that power turned into heat that needed forced-air cooling.

Which room-sized analogue machine was the Army's main trajectory calculator before ENIAC?

The differential analyzer was the standard tool for firing tables, but it was too slow for wartime demand, and that backlog led to ENIAC.

How many simple additions or subtractions per second could an ENIAC accumulator perform?

With 5,000 additions a second, ENIAC could compute a 60-second shell trajectory in about 30 seconds, faster than the shell itself could fly.

Eckert's 1944 memory design for later computers stored pulses as sound waves in which liquid?

Mercury: pulses travelled through the tank as sound waves and were reshaped and fed back in, and his BINAC computer used that memory.

Most computers work in binary, but which number system did ENIAC's arithmetic use?

Decimal: ENIAC counted pulses on rings of ten positions, electronically copying the digit wheels of a mechanical adding machine.

Eckert said ENIAC was about a thousand times faster than which electromechanical computer, completed in 1944 for the US Navy?

The Harvard Mark I ran on relays, shafts and clutches, and ENIAC's all-electronic design let its 1946 demonstration leave that machine far behind.

After engineers improved reliability, about how often did one of ENIAC's vacuum tubes fail?

About every two days, and the maintenance team learned to track down and replace the failed tube in about 15 minutes.

In 1950, Eckert and Mauchly's struggling computer company was bought by a firm originally known for making what?

Typewriters: the buyer kept Eckert on, and he went on to become one of its executives.

How was a new program originally entered into ENIAC?

By plugging cables and setting switches, which meant days of work for each new problem before a single calculation could run.

How many women made up ENIAC's original team of programmers?

Six, and their role went largely unrecognised until the 1990s, when the six were finally honoured and inducted into a technology hall of fame.

For ENIAC's 1946 public debut, its small neon indicator bulbs were covered with halves of what?

Ping-pong balls: the flashing panels made such an impression that this was how films and TV pictured computers for decades.

How were the ENIAC programmers classified by the Army, despite holding mathematics degrees?

Subprofessionals was the Army's label for the women computers, yet they taught themselves to program ENIAC with no manual to follow.

A historian once dismissed the women in ENIAC press photos as what?

Refrigerator ladies was a historian's dismissive guess about the women in the photos; undergraduate Kathy Kleiman later tracked them down and recorded their stories.

After leaving their university in 1946, ENIAC's inventors won a crucial $300,000 contract from which agency?

The Census Bureau went on to receive the company's first finished business computer in 1951, the machine that contract helped pay for.

To which Army site was ENIAC moved in 1947, where it ran until 1955?

Aberdeen Proving Ground, Maryland, is where ENIAC served as the Army's main computing engine for most of the next decade, turning out its ballistic tables.

ENIAC was retired in October 1955 in favour of which two more efficient computers?

EDVAC and ORDVAC took over its work, and ENIAC's retired panels were later split among museums and universities.

Which mathematician wrote the 1945 'First Draft' memo that spread the stored-program computer design?

John von Neumann was the memo's only named author, so the design became known as von Neumann architecture, leaving Eckert and Mauchly without the credit.

In 1953, ENIAC finally gained a 100-word internal memory built from what?

Magnetic cores, in a unit built by the Burroughs Corporation, gave ENIAC fast internal storage where punched cards had been too slow.

Which statistical technique first ran fully automatically on ENIAC in 1948?

The Monte Carlo method grew, Stanislaw Ulam recalled, from wondering about his chances of winning at solitaire while recovering from an illness.

Which 1973 court case voided the ENIAC patent and named John Atanasoff inventor of the electronic digital computer?

Honeywell v. Sperry Rand ended with Judge Earl Larson ruling that Eckert and Mauchly had derived the computer from Atanasoff's work, which Mauchly examined in 1941.

Which British machine ran its first program in June 1948, becoming the first computer to run a program held in electronic memory?

The Manchester Baby's design grew into a full-scale machine that paved the way for early commercially available computers.

Which British codebreaking computer, ten of which were built, stayed secret until the 1970s?

Colossus helped break the Lorenz cipher used by Hitler and his generals, yet its builders went unrecognised for decades because of the secrecy.

Which Navy mathematician joined ENIAC's inventors' company in 1949, believing computers should be easy to program?

Grace Hopper went on to develop FLOW-MATIC, an English-like programming language that laid the groundwork for COBOL.

What was the tiny integrated circuit that reproduced ENIAC's full functionality for its 50th anniversary called?

ENIAC-on-a-Chip was built by university students, shrinking a room-sized, 30-ton machine to fit in the palm of a hand.

Like ENIAC, which unfinished 19th-century design could branch to different instructions depending on a result?

Babbage's Analytical Engine was never finished, yet Ada Lovelace wrote a step-by-step calculation for it that is often called the first computer program.

Which politician turned part of ENIAC back on at its 50th anniversary celebration in 1996?

Al Gore used the day to urge Congress to keep funding science, pointing out that ENIAC itself had begun with a small government grant.

To choose ENIAC's wiring, its builders offered samples of insulation to which hungry animals?

Mice: gnawed wires were a real worry, so whichever insulation they liked least went into the machine.

Which content-management framework named its default theme 'Bartik' after ENIAC programmer Jean Bartik?

Drupal's Bartik theme honours Jean Bartik, whose ENIAC programming went largely unrecognised until historians brought it to light decades later.

Which Army liaison championed Eckert and Mauchly's electronic computer proposal in 1943?

Herman Goldstine won Army funding for a machine many thought had little chance of success, and ENIAC went on to prove the doubters wrong.

About how much did ENIAC cost to build, in 1940s dollars?

About $500,000, a bill that grew from the $61,700 of the Army's first six-month contract.

According to a popular story, what happened across the city whenever ENIAC was turned on?

The lights dimmed, or so the story went, but it never happened: the tale is a myth that has trailed the machine for decades.

What was ENIAC co-inventor John Mauchly hoping to predict when he first dreamed up an electronic computer?

The weather: but to win Army money he had to pitch the machine for artillery calculations instead.

Which 2010 documentary by LeAnn Erickson covers the ENIAC programmers' role?

Top Secret Rosies: The Female Computers of WWII, LeAnn Erickson's 2010 documentary, profiles the women hired to compute ballistics tables by hand, the job title the machine later took.