The sheer speed of the machine and its limited, but sufficiently versatile, programming mechanisms allowed the ENIAC to demonstrate that electronic computing could be applied to some of the nation's most pressing problems, such as the development of the hydrogen bomb. The significance of electronic computing to national security was an important factor in the birth of the modern computing industry.
During ENIAC’s first few months of life, its first application was to solve an important problem for the Manhattan Project, which was a secret military program to design and implement an atomic bomb design before Germany or Japan did. This initial project was originally supposed to be a test, to make sure that ENIAC could perform as required. However, the scheduled move of ENIAC to the Aberdeen Proving Ground was delayed so the Manhattan Project test could be completed before it was removed from the Moore School. (Moye)
During the test, many faults were found, of course because it was the first time that ENIAC was operational, performing its job. Solutions to these problems were introduced after the monstrous machine was moved to the Aberdeen Proving Ground in later 1946, arriving in January 1947. It was not fully assembled and operational until August 1947. (Moye)
Even though ENIAC was funded and overseen by the United States military, it was built as a large-scale, general-purpose digital electronic computer. Because ENIAC was the largest calculator and first non-mechanical one, it leads the way for future inventions. The possibilities were endless, for both the application of ENIAC to different, diverse projects, and what would be invented after ENIAC became obsolete.
ENIAC took about a year to design and 18 months to build. By the time it was completed, the war had been over for three months. The total cost of the project itself was 200 percent over budget, working out to be in the region of $500,000 altogether. It was an enormous machine weighing about 30 tons and filling a 30 by 50 foot room. It could multiply two numbers at the rate of 300 products per second, by finding the value of each product from a multiplication table stored in its memory. ENIAC was thus about 1,000 times faster than the previous generation of computers. ENIAC used 18,000 standard vacuum tubes, occupied 1800 square feet of floor space, and used about 180,000 watts of electricity. It used punched-card input and output.
ENIAC was formally introduced at the Moore School of Electrical Engineering of the University of Pennsylvania on February 15, 1946. Soon thereafter in July of the same year, it was accepted by the U.S. Army Ordnance Corps, and was put into service for official military duties. This was some four years after the original suggestion for a computer-assisted solution proposed by Mauchly. (Weik)
The ENIAC’s first few functional years proved to be difficult and frustrating. The operating and maintenance crews had the enormous task of making sure that the “largest collection of interconnected electronic circuitry then in existence and its thousands of components” (Weik) were operational simultaneously for the machine to work. The crews developed an elaborate “preventive-maintenance and testing program” (Weik) which eventually led to major mechanical modifications of the system.
The frequency and other statistical data on the lives of the vacuum tubes were compiled. These reports also led to many improvements to the system, specifically the vacuum tubes, as roughly 2000 of the computer's vacuum tubes were replaced each month by a team of six technicians. An intricate heat-removal system was also introduced, which was in great need. Despite the numerous improvements to ENIAC, downtimes were long and error-free running periods were short. (Weik)
ENIAC’s main drawback was that programming it was a nightmare because one had to essentially re-wire it to perform whatever task he wanted the computer to do. This was done with punch cards and switches in wiring plug boards. It could take a team many days, sometimes weeks of physically resetting the machine to perform a different task or to reprogram the machine. As a result, “ENIAC was converted into an internally stored fixed-program computer” (Weik) so that time would be saved by recalling previously programmed information. ENIAC’s primary use was for military ballistics, such as the firing and bomb tables used during World War II. However, ENIAC began to apply its power to the fields of “weather prediction, atomic energy calculations, cosmic-ray studies, thermal ignition, random-number studies, wind tunnel design, and many other scientific uses.” (Weik)
By February 1949, bugs and glitches had been reduced to a minimum. Downtime was shorter, and error-free running periods were longer. ENIAC was now the most sought-after machine in America, constantly being used to perform scientific and mathematic problems. It far surpassed all existing computers combined in processing speed and precision. It was the main machine for the United States Army and Air Force in the computation of all ballistic tables.
Despite some of its limitations ENIAC had achieved what it set out to do as calculations could be made within a fraction of a second. The speed of the computation made up for some of its drawbacks. Ballistic trajectories could take someone with a hand calculator twenty hours to compute, whereas ENIAC could perform this task in thirty seconds. This meant ENIAC was efficient in handling the particular programs for which it had been designed. ENIAC was used in many applications from 1946 to 1955, although it was not accessible to managers of businesses (Beer, 1966). It was later used for peaceful purposes such as the tabulation of U.S. census data.
Other factors enabling ENIAC’s success included the large sum of money invested into its design and development stages, thus enabling the machine to do exactly what it was set out to do. Planning is essential whatever the set task is but a good plan gives a better chance of meeting your goals efficiently and effectively. The primary aim of the designers was to achieve speed by making ENIAC as all electronic as possible. This worked for ENIAC as their goals had been met albeit a few drawbacks but some of these drawbacks could be tested and improved later on.
Another design objective was to make the electronics simple and reliable. This goal was achieved by utilizing vacuum tubes in a minimum of basic circuit combinations. To ensure reliable operation, circuits were built to rigidly tested standard components, which were operated at current, voltage, and power levels below their normal ratings. Accuracy of computation was achieved by designing the basic circuits to work independently of the changeable tolerances of their components. Numbers were not represented by electrical quantities, which could be affected by changes in tolerance but only by the presence or absence of dynamic pulses.
Despite the widespread use and popularity of the revolutionary ENIAC, its use as well as the use of any other electronic computer, was strictly for government agencies and not commercial use. The introduction of the new machine UNIVAC ushered in a new era of computing, whereas the corporate user was the main customer. (Weik) Corporations to calculate such things as payroll, billing, and other mathematical operations could now use high-speed machines.
With the advancement of computing, EDVAC and ORDVAC were introduced in 1952, and shared ENIAC’s workload. It became immediately obvious that in order to remain competitive and useful, ENIAC would have to make extensive modifications and upgrades. ENIAC did receive the necessary upgrades in late 1952. A new power supply, high-speed electronic shifter, which reduced the time, required for numerical shifting by 80% were both introduced. In July 1953, a 100-word static magnetic-core memory was added to facilitate the growing need for memory-based computing. (Weik)
Despite the modifications and the uptime of ENIAC was dramatically increased, it was no longer economically sound to continue using ENIAC, when other newer machines such as EDVAC and ORDVAC operated with higher processing power at a fraction of the cost. The workload was gradually moved to other machines and on October 2, 1955 at 11:45 PM, almost ten years after its launch, the power to ENIAC was terminated.
As we can see, the U.S. Army made known its need for faster computing speeds to the University of Pennsylvania’s Moore School, which responded with the world’s first all-digital computer. Even though ENIAC was introduced after the immediate need was over, it still performed its job very well for the nine years that it was in operation, had led to the development and improvement of many future computers.
Today, parts of the machine can be seen on display in various museums throughout the world, including the Smithsonian in Washington D.C., and in the very room where it was first constructed at the Moore School for Electrical Engineering of the University of Pennsylvania.
Bibliography
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MOYE, WILLIAM T. ENIAC: The Army-Sponsored Revolution, U.S. Army Research Laboratory. March 6, 2003.
WEIK, MARTIN H. The ENIAC Story, U.S. Army Research Laboratory. March 3, 2003.
BEER, S. (1966). Decision and Control, The meaning of Operational Research and Management Cybernetics.
RICHEY, KEVIN W. (1997) The Eniac. [online] (February 16, 1997), [cited 27 November 2003] available from < >.
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