John W. Mauchly

Main content

John W. Mauchly

and the Development of the ENIAC Computer

Early Years (1907-1925)

Early Years (1907-1925)

College Years (1925-1932)

College Years (1925-1932)

Life on the Margins (1932-1941)

Life on the Margins (1932-1941)

Early Experiments

Early Experiments

World War II & the Moore School

World War II & the Moore School

Project X: The ENIAC Project (1942-1946)

Project X: The ENIAC Project (1942-1946)

The Atanasoff Controversy

The Atanasoff Controversy

The ENIAC

The ENIAC

Technical Description of the ENIAC

Technical Description of the ENIAC

The EDVAC Design

The EDVAC Design

Out on Their Own (1946-1951)

Out on Their Own (1946-1951)

The UNIVAC & the Legacy of the ENIAC

The UNIVAC & the Legacy of the ENIAC

Moving Back into an Independent Career

Moving Back into an Independent Career

Conclusion

Conclusion

General View of the ENIAC

Curated by Asaf Goldschmidt and Atsushi Akera
Department of History and Sociology of Science, University of Pennsylvania

This exhibition provides an overview history of the emergence of modern computing as seen through the eyes of one of its two principal inventors, John W. Mauchly (1907-1980), who worked at the Moore School of Electrical Engineering between 1941 and 1946, and whose papers are held at the University of Pennsylvania.

 

Introduction

Mauchly
Photograph of John W. Mauchly, ca. 1940-50.

 

The year 1996 marks the fiftieth anniversary of the ENIAC computer, the first large-scale general-purpose electronic computer. Built at the University of Pennsylvania's Moore School of Electrical Engineering, ENIAC is an acronym for "Electronic Numerical Integrator and Computer," but its birth lay in World War II as a classified military project known only as Project PX. The ENIAC is important historically, because it laid the foundations for the modern electronic computing industry. More than any other machine, the ENIAC demonstrated that high-speed digital computing was possible using the then-available vacuum tube technology.

We attempt in this exhibition to portray a history of the emergence of modern computing as seen through the eyes of one of its two principal inventors, John W. Mauchly (1907-1980), who worked at the Moore School of Electrical Engineering between 1941 and 1946. In focusing on Mauchly, we do not claim that he was the principal or sole inventor of this machine. At the very least, this credit would have to be shared with J. Presper Eckert (1919-1995), who at the time of the ENIAC's inception in 1942 had barely completed his Master's degree. If Mauchly had initially conceived of ENIAC's architecture, it was Eckert who possessed the engineering skills to bring the idea to life. We chose in this exhibit to focus on the career of John Mauchly, partly to reveal the historical complexities of the process of invention that can only be seen through close attention to a single individual. More pragmatically, we chose John Mauchly in order to introduce scholars to the John Mauchly Papers, held by the Department of Special Collections, Van Pelt Library, University of Pennsylvania.

 

College Years

J. W. Mauchly, advertisement for tutoring services, n.d.
J. W. Mauchly, advertisement
for tutoring services, n.d.

 

In the twentieth century college education in the United States has become a rite of passage, a way for youths to make the transition into adulthood. It represents a time of departure away from home, often to a place calculated to be not too convenient for one's parents. Mauchly entered Johns Hopkins as an undergraduate in the Electrical Engineering program, based on the stipulations of his scholarship.

Home, however, had become a more troubled place. During one of his scientific voyagessometime before 1925S.J. Mauchly had contracted a chronic illness. Unwilling to let go of his scientific work, Mauchly's father continued to work excessive hours, which only made his condition worse. Between 1925 and 1928, Mauchly received postcards from the New Jersey shore, where his family went to help father's convalescence.

Torn between the material pleasures of life and the prestige of his father's intellectual career, Mauchly nevertheless found himself increasingly drawn towards the latter. During his freshman year, Mauchly complained to his father about the General Engineering course, which attempted to provide a more theoretical foundation for engineering. By the end of his second year Mauchly began to feel that engineering was too mundane. In 1927 he made use of a special provision that allowed outstanding students to enroll directly in a Ph.D. program before completing their undergraduate degrees and transferred to the graduate physics program of the university.

Mauchly's father passed away around Christmas in 1928. On the very envelope that carried one of his mother's urgent letters, Mauchly scribbled some notes from his studies. Perhaps a turn to his work was a way of coping with his fears of loss. A series of scholarships permitted Mauchly to continue with his studies after his father's death. Mauchly submitted his dissertation on "The Third Positive Group of Carbon Monoxide Bands" to the faculty of Johns Hopkins University in 1932.

Conclusion

Mauchly and Eckert receiving the Harry Goode Medal of the American Federation of Information Processing Societies in 1966.
Mauchly and Eckert receiving the Harry Goode Medal of the
American Federation of Information Processing Societies in 1966.

 

In October 1973 Judge Earl Larson of the U.S. District Court in Minnesota rendered a decision invalidating the ENIAC patent. But rather than being a clear judgement as to who invented the electronic computer, this decision and the law suit, Honeywell v. Sperry-Rand, have done more to polarize opinions with respect to the varied contributions of many different individuals. In fact, this decision points to some of the limitations of the U.S. patent system with respect to complex technologies. Namely, the U.S. patent system sets forth certain pressures to name a sole inventor when invention itself is a often a highly collaborative process. We hope that this exhibition reveals something of the complexities involved in the process of invention. We hope also that in approaching the fifty-year mark of modern computing, we can recognize the diverse contributions of individuals, regardless of what we individually consider to be its origins.

Mauchly had a successful career. Whatever the various turns in his life, he designed and oversaw the development of the first large-scale general purpose electronic computer. He created a start-up venture which he eventually sold at a profit to the company that went on to manufacture his computer. His work as a consultant was also successful. Moreover, Mauchly received academic recognition for his contributions: the Potts Medal of the Franklin Institute in 1949 and the Harry Goode Medal of the American Federation of Information Processing Societies in 1966.

With all these accomplishments behind him, Mauchly retired to the quiet suburb of Ambler, Pennsylvania, just outside of Philadelphia. He passed away on 9 January 1980 at the age of seventy-two.

Further reading:
Paul Freiberger & Michael Swaine. Fire in the Valley: The Making of the Personal Computer. New York: McGraw-Hill, 2000.
Scott McCartney. ENIAC: The Triumphs and Tragedies of the World's First Computer. New York: Walker & Company, 1999.

 

Conclusion

Mauchly and Eckert receiving the Harry Goode Medal of the American Federation of Information Processing Societies in 1966.
Mauchly and Eckert receiving the Harry Goode Medal of the
American Federation of Information Processing Societies in 1966.

 

In October 1973 Judge Earl Larson of the U.S. District Court in Minnesota rendered a decision invalidating the ENIAC patent. But rather than being a clear judgement as to who invented the electronic computer, this decision and the law suit, Honeywell v. Sperry-Rand, have done more to polarize opinions with respect to the varied contributions of many different individuals. In fact, this decision points to some of the limitations of the U.S. patent system with respect to complex technologies. Namely, the U.S. patent system sets forth certain pressures to name a sole inventor when invention itself is a often a highly collaborative process. We hope that this exhibition reveals something of the complexities involved in the process of invention. We hope also that in approaching the fifty-year mark of modern computing, we can recognize the diverse contributions of individuals, regardless of what we individually consider to be its origins.

Mauchly had a successful career. Whatever the various turns in his life, he designed and oversaw the development of the first large-scale general purpose electronic computer. He created a start-up venture which he eventually sold at a profit to the company that went on to manufacture his computer. His work as a consultant was also successful. Moreover, Mauchly received academic recognition for his contributions: the Potts Medal of the Franklin Institute in 1949 and the Harry Goode Medal of the American Federation of Information Processing Societies in 1966.

With all these accomplishments behind him, Mauchly retired to the quiet suburb of Ambler, Pennsylvania, just outside of Philadelphia. He passed away on 9 January 1980 at the age of seventy-two.

Further reading:
Paul Freiberger & Michael Swaine. Fire in the Valley: The Making of the Personal Computer. New York: McGraw-Hill, 2000.
Scott McCartney. ENIAC: The Triumphs and Tragedies of the World's First Computer. New York: Walker & Company, 1999.

 

Early Experiments

J. W. Mauchly, chart of radio transmission disturbance over North Atlantic, 1937-38, from article, "Depression of Mid-day Ion Densities in the F(sub-2)-region of the Ionosphere related to the Diurnal Variation of H.," for Union Radio Scientique Internaionale, 1938.
J. W. Mauchly, chart of radio transmission disturbance
over North Atlantic, 1937-38, from article, "Depression of
Mid-day Ion Densities in the F(sub-2)-region of the Ionosphere
related to the Diurnal Variation of H.," for Union Radio
Scientique Internaionale, 1938.
 

 

Ultimately, it was the difficulty Mauchly experienced in getting his colleagues to accept his meteorological studies that prompted him to explore digital, electronic methods of computation. Established meteorologists were highly skeptical of the statistical approaches to the study of their field. Mauchly had worked for two summers at the Department of Terrestrial Magnetism of the Carnegie Institute of Washington, D.C., studying data on diurnal variations in the ion densities of the ionosphere. His paper on the subject, however, had been rejected, especially for its use of "so short a period" of analysis. Because Mauchly had followed these variations for only a month, reviewers considered his conclusions unwarranted. And yet the information they wanted required more extensive data analysis than Mauchly could easily perform with the resources at his disposal.

This fact prompted Mauchly to begin some early experiments with digital electronic computing circuitry. His two years as an undergraduate in an electrical engineering department no doubt fueled this new twist in his research. His resources were small, as was the scale of these trials. Among the circuits that he built were such basic elements such as a "flip-flop," which could essentially store the "1s" and "0s" that make up the information stored by all digital computers. Mauchly built some of the circuits using neon bulbs rather than the more expensive vacuum tubes, which meant that they did not have the full performance of vacuum tube circuitry. Nor was he the first to discover these devices. Electronic counters and other devices had been developed earlier. Nevertheless, Mauchly was beginning to figure out the basic concepts behind electronic computing circuitry himself.

This new interest eventually led Mauchly to the University of Pennsylvania. He received a letter from Knox McIlwain, the Director of Engineering Defense Training at the university's Moore School of Electrical Engineering. The Moore School stood at the heart of a strong regional electrical industry that had grown with the popularity of radio, telephony, and other electronic technologies. With the prospects of war looming, the military began to seek young engineers trained to operate the electronic weapons and communications systems that were becoming an increasing part of U.S. armaments. The Moore School stepped forward to accept a contract from the U.S. Army to teach a special ten-week course on Electrical Engineering for Defense Industries directed to students with a degree in mathematics or physics. McIlwain had written Mauchly as the Chair of Ursinus' Physics Department, inquiring whether he knew of prospective students. But Mauchly wanted to learn more about electronics himself, not the least because of his interest in computing circuitry.

The outcome was that in 1941 Mauchly himself enrolled in this program, even though he already held a Ph.D. in physics.

Early Experiments

J. W. Mauchly, chart of radio transmission disturbance over North Atlantic, 1937-38, from article, "Depression of Mid-day Ion Densities in the F(sub-2)-region of the Ionosphere related to the Diurnal Variation of H.," for Union Radio Scientique Internaionale, 1938.
J. W. Mauchly, chart of radio transmission disturbance
over North Atlantic, 1937-38, from article, "Depression of
Mid-day Ion Densities in the F(sub-2)-region of the Ionosphere
related to the Diurnal Variation of H.," for Union Radio
Scientique Internaionale, 1938.
 

 

Ultimately, it was the difficulty Mauchly experienced in getting his colleagues to accept his meteorological studies that prompted him to explore digital, electronic methods of computation. Established meteorologists were highly skeptical of the statistical approaches to the study of their field. Mauchly had worked for two summers at the Department of Terrestrial Magnetism of the Carnegie Institute of Washington, D.C., studying data on diurnal variations in the ion densities of the ionosphere. His paper on the subject, however, had been rejected, especially for its use of "so short a period" of analysis. Because Mauchly had followed these variations for only a month, reviewers considered his conclusions unwarranted. And yet the information they wanted required more extensive data analysis than Mauchly could easily perform with the resources at his disposal.

This fact prompted Mauchly to begin some early experiments with digital electronic computing circuitry. His two years as an undergraduate in an electrical engineering department no doubt fueled this new twist in his research. His resources were small, as was the scale of these trials. Among the circuits that he built were such basic elements such as a "flip-flop," which could essentially store the "1s" and "0s" that make up the information stored by all digital computers. Mauchly built some of the circuits using neon bulbs rather than the more expensive vacuum tubes, which meant that they did not have the full performance of vacuum tube circuitry. Nor was he the first to discover these devices. Electronic counters and other devices had been developed earlier. Nevertheless, Mauchly was beginning to figure out the basic concepts behind electronic computing circuitry himself.

This new interest eventually led Mauchly to the University of Pennsylvania. He received a letter from Knox McIlwain, the Director of Engineering Defense Training at the university's Moore School of Electrical Engineering. The Moore School stood at the heart of a strong regional electrical industry that had grown with the popularity of radio, telephony, and other electronic technologies. With the prospects of war looming, the military began to seek young engineers trained to operate the electronic weapons and communications systems that were becoming an increasing part of U.S. armaments. The Moore School stepped forward to accept a contract from the U.S. Army to teach a special ten-week course on Electrical Engineering for Defense Industries directed to students with a degree in mathematics or physics. McIlwain had written Mauchly as the Chair of Ursinus' Physics Department, inquiring whether he knew of prospective students. But Mauchly wanted to learn more about electronics himself, not the least because of his interest in computing circuitry.

The outcome was that in 1941 Mauchly himself enrolled in this program, even though he already held a Ph.D. in physics.

Early Years

Diploma
Certificate issued to J. W. Mauchly by McKinley Technical High School,
Washington, D.C., 10 June 1925

 

John William Mauchly was born 30 August 1907 in Cincinnati, Ohio, to Sebastian J. and Rachel Mauchly. During Mauchly's childhood, his father received an appointment as a physicist at the Carnegie Institute of Washington, D.C., a prestigious scientific institution established during the interwar years as part of an effort to raise the level of scientific research in the United States. S.J. Mauchly had come to the Carnegie Institute to study the phenomena of terrestrial magnetism, a subject that had suddenly become important after the connection between magnetism and radio propagation became increasingly clear. But this research often took the father away from home, as when he wrote to his eight-year-old son from New York's Hotel St. George. The letter came as S.J. Mauchly prepared for one of his ocean voyages aboard a meteorological research vessel.

Shortly after they moved to Washington, D.C., in 1913, the family settled into the comfortable suburb of Chevy Chase, Maryland. Located near other major scientific facilities such as the National Bureau of Standards, this suburb housed many scientists, engineers, and other well-educated professionals. This is not to suggest that Mauchly's upbringing was exceptional. Mauchly was not raised like the Hungarian physicists or the German mathematicians whose intellectual virtuosity had stunned the world during the 1930s. Mauchly represented part of a nascent community of technical elites that was emerging in the United States. Quite apart from brilliant minds like Albert Einstein or Claude Hilbert, it was the greater ranks of U.S. born scientists and engineers who were to carry the nation into and beyond the extensive technical developments of World War II.

His father's occupation afforded Mauchly a good education, beginning with his schooling at the McKinley Technical High School in downtown Washington. Still, in balancing his school work with tennis matches and walks through the woods, or one of Edgar Allen Poe's ghost stories read in the dark among friends, Mauchly led a reasonably comfortable existence of an upper middle-class youth. It is only in such items as his "Daily Record," where Mauchly meticulously recorded his daily sleep, that one perceives a child socialized into a particular, technical way of thought. Perhaps Mauchly had also drawn some inspiration from Benjamin Franklin's Autobiography. In any case, his academic achievements brought him the Engineering Scholarship of the State of Maryland, which enabled him to enroll at Johns Hopkins University in the fall of 1925.

 

Early Years

Diploma
Certificate issued to J. W. Mauchly by McKinley Technical High School,
Washington, D.C., 10 June 1925

 

John William Mauchly was born 30 August 1907 in Cincinnati, Ohio, to Sebastian J. and Rachel Mauchly. During Mauchly's childhood, his father received an appointment as a physicist at the Carnegie Institute of Washington, D.C., a prestigious scientific institution established during the interwar years as part of an effort to raise the level of scientific research in the United States. S.J. Mauchly had come to the Carnegie Institute to study the phenomena of terrestrial magnetism, a subject that had suddenly become important after the connection between magnetism and radio propagation became increasingly clear. But this research often took the father away from home, as when he wrote to his eight-year-old son from New York's Hotel St. George. The letter came as S.J. Mauchly prepared for one of his ocean voyages aboard a meteorological research vessel.

Shortly after they moved to Washington, D.C., in 1913, the family settled into the comfortable suburb of Chevy Chase, Maryland. Located near other major scientific facilities such as the National Bureau of Standards, this suburb housed many scientists, engineers, and other well-educated professionals. This is not to suggest that Mauchly's upbringing was exceptional. Mauchly was not raised like the Hungarian physicists or the German mathematicians whose intellectual virtuosity had stunned the world during the 1930s. Mauchly represented part of a nascent community of technical elites that was emerging in the United States. Quite apart from brilliant minds like Albert Einstein or Claude Hilbert, it was the greater ranks of U.S. born scientists and engineers who were to carry the nation into and beyond the extensive technical developments of World War II.

His father's occupation afforded Mauchly a good education, beginning with his schooling at the McKinley Technical High School in downtown Washington. Still, in balancing his school work with tennis matches and walks through the woods, or one of Edgar Allen Poe's ghost stories read in the dark among friends, Mauchly led a reasonably comfortable existence of an upper middle-class youth. It is only in such items as his "Daily Record," where Mauchly meticulously recorded his daily sleep, that one perceives a child socialized into a particular, technical way of thought. Perhaps Mauchly had also drawn some inspiration from Benjamin Franklin's Autobiography. In any case, his academic achievements brought him the Engineering Scholarship of the State of Maryland, which enabled him to enroll at Johns Hopkins University in the fall of 1925.

 

Life on the Margins

New Science Building, Ursinus College
Post card showing "New Science Building, Ursinus College.

 

Mauchly's career was interrupted by the Great Depression. While university faculty as a whole did not suffer the fate of the blue-collar work force, newly-minted academics had a difficult time finding appointments during the early 1930s. Mauchly had received his Ph.D. from one of the most prestigious institutions in the world. Yet, his field of studymolecular spectroscopywas one that belonged to a previous wave of scientific interest. During the 1930s, nuclear physics increasingly became the hot topic for research, which absorbed many of the new positions opening up in leading physics departments. Mauchly approached several research institutions but was turned down by all of them, including the Carnegie Institution of Washington, D.C., the place where his father had worked.

Mauchly eventually accepted a professorship in physics at Ursinus College, a small, liberal arts college located in the outskirts of Philadelphia. There he taught introductory physics courses, including some involving experimental techniques. However, the circumstances at Ursinus did not suit the research interests to which he had been so thoroughly conditioned. Physics itself was changing, and by the 1930s the leading laboratories in the country were equipped with accelerators, spectrometers, and other instruments beyond the resources of many state universities, let alone an individual professor working at a liberal arts college. The main lines of research in physics remained closed to Mauchly, much as many lines of investigation were closed to researchers living in third-world countries, who had no access to expensive equipment.

But much as the best papers in mathematics and theoretical physics eventually emerged from countries like India, it is important to view Mauchly's efforts at Ursinus as part of a strategy for conducting research within the limited resources available to him. Among his efforts were attempts to develop analog electronic instruments suitable for specific lines of research. Mauchly also discovered a wealth of meteorological data, which by the 1930s were being collected from field stations located all around the globe. Such data were available in tabular form and were transportable to an isolated researcher. Their analysis, however, required extensive calculations. Mauchly actually sought more generally to improve calculating instruments, thinking as much about the needs of his students as his own research. This preoccupation with making calculations quicker and easier led Mauchly towards electronic calculating machines.

 

Life on the Margins

New Science Building, Ursinus College
Post card showing "New Science Building, Ursinus College.

 

Mauchly's career was interrupted by the Great Depression. While university faculty as a whole did not suffer the fate of the blue-collar work force, newly-minted academics had a difficult time finding appointments during the early 1930s. Mauchly had received his Ph.D. from one of the most prestigious institutions in the world. Yet, his field of studymolecular spectroscopywas one that belonged to a previous wave of scientific interest. During the 1930s, nuclear physics increasingly became the hot topic for research, which absorbed many of the new positions opening up in leading physics departments. Mauchly approached several research institutions but was turned down by all of them, including the Carnegie Institution of Washington, D.C., the place where his father had worked.

Mauchly eventually accepted a professorship in physics at Ursinus College, a small, liberal arts college located in the outskirts of Philadelphia. There he taught introductory physics courses, including some involving experimental techniques. However, the circumstances at Ursinus did not suit the research interests to which he had been so thoroughly conditioned. Physics itself was changing, and by the 1930s the leading laboratories in the country were equipped with accelerators, spectrometers, and other instruments beyond the resources of many state universities, let alone an individual professor working at a liberal arts college. The main lines of research in physics remained closed to Mauchly, much as many lines of investigation were closed to researchers living in third-world countries, who had no access to expensive equipment.

But much as the best papers in mathematics and theoretical physics eventually emerged from countries like India, it is important to view Mauchly's efforts at Ursinus as part of a strategy for conducting research within the limited resources available to him. Among his efforts were attempts to develop analog electronic instruments suitable for specific lines of research. Mauchly also discovered a wealth of meteorological data, which by the 1930s were being collected from field stations located all around the globe. Such data were available in tabular form and were transportable to an isolated researcher. Their analysis, however, required extensive calculations. Mauchly actually sought more generally to improve calculating instruments, thinking as much about the needs of his students as his own research. This preoccupation with making calculations quicker and easier led Mauchly towards electronic calculating machines.

 

Moving Back into an Independent Career

Photograph of Mauchly with "SkedFlo, Model MCX-30," n.d.
Photograph of Mauchly with "SkedFlo, Model MCX-30," n.d.

 

When Thomas Edison developed his system of electrical lighting, he successfully produced enough elements of his system to stand at the helm of a vast commercial empire. As historian Thomas Hughes has described Edison's career (see his Networks of Power), Edison was a system builder, an inventor-entrepreneur, who could garner the necessary financial, political, and social interests in electrification to develop a truly successful venture.

Had World War II and the Cold War not taken place, perhaps Mauchly would have had the opportunity to do the same. But the circumstances were different. In designing a general purpose computer, Mauchly had built a machine that inherently served more applications than he could possibly envision. In the wake of World War II, the digital electronic computer took on a military significance that an individual scientist like Mauchly could not be trusted to oversee. Postwar planning for computer development fell to scientific advisors and military strategists who dealt with such technologies as the hydrogen bomb, supersonic combat aircraft, anti-aircraft missiles, and the nation's strategic air defense system. While Mauchly continued to try to advise the Univac Division of Remington Rand on the various applications of computer systems, the larger marketing and development staff of the corporation supplanted the usefulness of his knowledge.

But the general-purpose nature of computers also opened up a new window for Mauchly. Given the many possible applications for computers and the relative ignorance of their users, markets emerged for people who could provide advice on the use of computers. This demand, however, existed on the side of Remington Rand's customers, not within Remington Rand itself. Thus, Mauchly chose to leave the firm in 1959, setting up his own consulting firm, Mauchly Associates, and yet another firm in the late 1960s called Dynatrend. He did not limit himself to digital electronic computers. His focus had now shifted towards quantitative project planning and management techniques such as the Critical Path Method.

Mauchly provided his consulting services for the construction of other industries. Mauchly had thus returned to the life of an independent thinker, now working in the margins of a large industry.

 

Moving Back into an Independent Career

Photograph of Mauchly with "SkedFlo, Model MCX-30," n.d.
Photograph of Mauchly with "SkedFlo, Model MCX-30," n.d.

 

When Thomas Edison developed his system of electrical lighting, he successfully produced enough elements of his system to stand at the helm of a vast commercial empire. As historian Thomas Hughes has described Edison's career (see his Networks of Power), Edison was a system builder, an inventor-entrepreneur, who could garner the necessary financial, political, and social interests in electrification to develop a truly successful venture.

Had World War II and the Cold War not taken place, perhaps Mauchly would have had the opportunity to do the same. But the circumstances were different. In designing a general purpose computer, Mauchly had built a machine that inherently served more applications than he could possibly envision. In the wake of World War II, the digital electronic computer took on a military significance that an individual scientist like Mauchly could not be trusted to oversee. Postwar planning for computer development fell to scientific advisors and military strategists who dealt with such technologies as the hydrogen bomb, supersonic combat aircraft, anti-aircraft missiles, and the nation's strategic air defense system. While Mauchly continued to try to advise the Univac Division of Remington Rand on the various applications of computer systems, the larger marketing and development staff of the corporation supplanted the usefulness of his knowledge.

But the general-purpose nature of computers also opened up a new window for Mauchly. Given the many possible applications for computers and the relative ignorance of their users, markets emerged for people who could provide advice on the use of computers. This demand, however, existed on the side of Remington Rand's customers, not within Remington Rand itself. Thus, Mauchly chose to leave the firm in 1959, setting up his own consulting firm, Mauchly Associates, and yet another firm in the late 1960s called Dynatrend. He did not limit himself to digital electronic computers. His focus had now shifted towards quantitative project planning and management techniques such as the Critical Path Method.

Mauchly provided his consulting services for the construction of other industries. Mauchly had thus returned to the life of an independent thinker, now working in the margins of a large industry.

 

Out on Their Own

Photograph of quarters of the  Electronic Control Company, 1949.
Photograph of quarters of the Electronic Control Company, 1949.

As if the other controversies were not enough, Mauchly and Eckert were forced to resign from the Moore School not long after the public announcement of the ENIAC. While in the 1990s it would be unthinkable for a university not to have a well-developed patent policy, this was the case at the University of Pennsylvania in the 1940s. The university did have a general policy barring its faculty from obtaining private patents based on university research. But the ENIAC was supported through military funds and not through the university's own resources. Given this ambiguity, Dean Harold Pender of the Moore School made a special allowance for Mauchly and Eckert to apply independently for the ENIAC patent. After World War II the military demanded all academic institutions seeking research contracts to have uniform patent policies, so the University demanded that Mauchly and Eckert turn their patent rights back over to the University. Having done the work of filing the patent themselves, Mauchly and Eckert were not about to oblige. This decision ultimately led to their resignations, effective 31 March 1946.

Mauchly and Eckert ultimately formed the Electronic Controls Company in downtown Philadelphia. Eckert assumed the task of designing a new computer system, more or less along the lines laid out in von Neumann's report. Mauchly, meanwhile, took on the more general task of identifying the uses of electronic computers. This duty was important, because as a private venture the Electronic Controls Company had to sell its machines if it were to survive.

The company's first client was the U.S. Census Bureau. Mauchly recognized that the decennial census was but four years away and reasoned that he could sell a computer to the Census Bureau as a way of reducing its costs for tabulating its immense volume of data. As it turns out, the Census was attracted more to the speed rather than the economies afforded by the proposed new computer. Increasingly, manufacturers and government policy makers were seeking timely information about the national economy. The Census Bureau had expanded its operations to collect relevant data, but its processing capabilities were more limited, particularly when it involved some of the newer statistical sampling techniques

Given the great concerns for postwar economic recovery, Mauchly found the Census Bureau very receptive to his proposals. The result was a contract, placed under the administration of the National Bureau of Standards, to have the Electronic Controls Company deliver a large-scale electronic computer. This work proceeded as the company was officially incorporated as the Eckert- Mauchly Computer Corporation (EMCC) in December of 1948.

 

Out on Their Own

Photograph of quarters of the  Electronic Control Company, 1949.
Photograph of quarters of the Electronic Control Company, 1949.

As if the other controversies were not enough, Mauchly and Eckert were forced to resign from the Moore School not long after the public announcement of the ENIAC. While in the 1990s it would be unthinkable for a university not to have a well-developed patent policy, this was the case at the University of Pennsylvania in the 1940s. The university did have a general policy barring its faculty from obtaining private patents based on university research. But the ENIAC was supported through military funds and not through the university's own resources. Given this ambiguity, Dean Harold Pender of the Moore School made a special allowance for Mauchly and Eckert to apply independently for the ENIAC patent. After World War II the military demanded all academic institutions seeking research contracts to have uniform patent policies, so the University demanded that Mauchly and Eckert turn their patent rights back over to the University. Having done the work of filing the patent themselves, Mauchly and Eckert were not about to oblige. This decision ultimately led to their resignations, effective 31 March 1946.

Mauchly and Eckert ultimately formed the Electronic Controls Company in downtown Philadelphia. Eckert assumed the task of designing a new computer system, more or less along the lines laid out in von Neumann's report. Mauchly, meanwhile, took on the more general task of identifying the uses of electronic computers. This duty was important, because as a private venture the Electronic Controls Company had to sell its machines if it were to survive.

The company's first client was the U.S. Census Bureau. Mauchly recognized that the decennial census was but four years away and reasoned that he could sell a computer to the Census Bureau as a way of reducing its costs for tabulating its immense volume of data. As it turns out, the Census was attracted more to the speed rather than the economies afforded by the proposed new computer. Increasingly, manufacturers and government policy makers were seeking timely information about the national economy. The Census Bureau had expanded its operations to collect relevant data, but its processing capabilities were more limited, particularly when it involved some of the newer statistical sampling techniques

Given the great concerns for postwar economic recovery, Mauchly found the Census Bureau very receptive to his proposals. The result was a contract, placed under the administration of the National Bureau of Standards, to have the Electronic Controls Company deliver a large-scale electronic computer. This work proceeded as the company was officially incorporated as the Eckert- Mauchly Computer Corporation (EMCC) in December of 1948.

 

Out on Their Own

Photograph of quarters of the  Electronic Control Company, 1949.
Photograph of quarters of the Electronic Control Company, 1949.

As if the other controversies were not enough, Mauchly and Eckert were forced to resign from the Moore School not long after the public announcement of the ENIAC. While in the 1990s it would be unthinkable for a university not to have a well-developed patent policy, this was the case at the University of Pennsylvania in the 1940s. The university did have a general policy barring its faculty from obtaining private patents based on university research. But the ENIAC was supported through military funds and not through the university's own resources. Given this ambiguity, Dean Harold Pender of the Moore School made a special allowance for Mauchly and Eckert to apply independently for the ENIAC patent. After World War II the military demanded all academic institutions seeking research contracts to have uniform patent policies, so the University demanded that Mauchly and Eckert turn their patent rights back over to the University. Having done the work of filing the patent themselves, Mauchly and Eckert were not about to oblige. This decision ultimately led to their resignations, effective 31 March 1946.

Mauchly and Eckert ultimately formed the Electronic Controls Company in downtown Philadelphia. Eckert assumed the task of designing a new computer system, more or less along the lines laid out in von Neumann's report. Mauchly, meanwhile, took on the more general task of identifying the uses of electronic computers. This duty was important, because as a private venture the Electronic Controls Company had to sell its machines if it were to survive.

The company's first client was the U.S. Census Bureau. Mauchly recognized that the decennial census was but four years away and reasoned that he could sell a computer to the Census Bureau as a way of reducing its costs for tabulating its immense volume of data. As it turns out, the Census was attracted more to the speed rather than the economies afforded by the proposed new computer. Increasingly, manufacturers and government policy makers were seeking timely information about the national economy. The Census Bureau had expanded its operations to collect relevant data, but its processing capabilities were more limited, particularly when it involved some of the newer statistical sampling techniques

Given the great concerns for postwar economic recovery, Mauchly found the Census Bureau very receptive to his proposals. The result was a contract, placed under the administration of the National Bureau of Standards, to have the Electronic Controls Company deliver a large-scale electronic computer. This work proceeded as the company was officially incorporated as the Eckert- Mauchly Computer Corporation (EMCC) in December of 1948.

 

Project X: The ENIAC Project

Mauchly drafted a memo during the summer of 1942, outlining the first large-scale digital electronic computer designed for general numerical computations. Having spent a year at the Moore School, he had come to have a better understanding of electronic engineering and the mathematics of ballistics computations. A budding association with J. Presper Eckert, who had been the laboratory assistant for the course that Mauchly had taken during the previous summer, provided valuable technical support. Indeed, Mauchly and Eckert together discussed what it might entail to build a large electronic computer.

The memo was carefully drafted to bring together the various interests that would justify an electronic computing project. This included the ability of such a computer to produce ballistics tablesa task on which the Moore School was falling increasingly behind. It also drew attention to the engineering expertise of the Moore School. Most important, Mauchly laid out the design as a general purpose digital computer. His own research interests in meteorology and cryptography precluded a device limited only to ballistics computations. Too esoteric for the Moore School's senior faculty, and perhaps in conflict with a separate effort to produce an electronic version of the differential analyzer, Mauchly's memo remained idle for the time being.

It did become the basis for a formal proposal submitted the following year. At this point, the impetus came from Lt. Herman Goldstine of the Ballistics Research Laboratory. Having received a Ph.D. in applied mathematics from the University of Chicago, Goldstine quickly assessed the computational advantages of Mauchly's machine. Excited at the prospects of having a machine that could eliminate the backlog of ballistics computations, Goldstine encouraged both the Moore School and the Ordnance Department to support the project. An official proposal was submitted in April of 1943, and the resulting contract, Project PX, gave birth to the ENIAC computer. All together, the U.S. Army provided approximately $500,000 for the ENIAC's development.

Mauchly was never officially a researcher on Project PX. Given his designated duties as an instructor, he was permitted only to act as a consultant to the project. In his spare time, however, Mauchly worked closely with Eckert and others to realize the ENIAC computer. An extensive collection of laboratory notebooks, blueprints, and correspondence that document the ENIAC work can be found in the University Archives and Records Center of the University of Pennsylvania.

Accumulator Decade Plug-in Unit, from "ENIAC Progress Report," 30 June 1944 (ENIAC Museum, SEAS, UP).
Accumulator Decade Plug-in Unit, from "ENIAC Progress Report," 30 June 1944 (ENIAC Museum, SEAS, UP).

Further reading:
“The ENIAC Story” by Martin H. Weik - January-February 1961 issue of ORDNANCE, The Journal of the American Ordnance Association.
ENIAC 50: The Birth of the Information Age - School of Engineering and Applied Science, University of Pennsylvania.

Project X: The ENIAC Project

Mauchly drafted a memo during the summer of 1942, outlining the first large-scale digital electronic computer designed for general numerical computations. Having spent a year at the Moore School, he had come to have a better understanding of electronic engineering and the mathematics of ballistics computations. A budding association with J. Presper Eckert, who had been the laboratory assistant for the course that Mauchly had taken during the previous summer, provided valuable technical support. Indeed, Mauchly and Eckert together discussed what it might entail to build a large electronic computer.

The memo was carefully drafted to bring together the various interests that would justify an electronic computing project. This included the ability of such a computer to produce ballistics tablesa task on which the Moore School was falling increasingly behind. It also drew attention to the engineering expertise of the Moore School. Most important, Mauchly laid out the design as a general purpose digital computer. His own research interests in meteorology and cryptography precluded a device limited only to ballistics computations. Too esoteric for the Moore School's senior faculty, and perhaps in conflict with a separate effort to produce an electronic version of the differential analyzer, Mauchly's memo remained idle for the time being.

It did become the basis for a formal proposal submitted the following year. At this point, the impetus came from Lt. Herman Goldstine of the Ballistics Research Laboratory. Having received a Ph.D. in applied mathematics from the University of Chicago, Goldstine quickly assessed the computational advantages of Mauchly's machine. Excited at the prospects of having a machine that could eliminate the backlog of ballistics computations, Goldstine encouraged both the Moore School and the Ordnance Department to support the project. An official proposal was submitted in April of 1943, and the resulting contract, Project PX, gave birth to the ENIAC computer. All together, the U.S. Army provided approximately $500,000 for the ENIAC's development.

Mauchly was never officially a researcher on Project PX. Given his designated duties as an instructor, he was permitted only to act as a consultant to the project. In his spare time, however, Mauchly worked closely with Eckert and others to realize the ENIAC computer. An extensive collection of laboratory notebooks, blueprints, and correspondence that document the ENIAC work can be found in the University Archives and Records Center of the University of Pennsylvania.

Accumulator Decade Plug-in Unit, from "ENIAC Progress Report," 30 June 1944 (ENIAC Museum, SEAS, UP).
Accumulator Decade Plug-in Unit, from "ENIAC Progress Report," 30 June 1944 (ENIAC Museum, SEAS, UP).

Further reading:
“The ENIAC Story” by Martin H. Weik - January-February 1961 issue of ORDNANCE, The Journal of the American Ordnance Association.
ENIAC 50: The Birth of the Information Age - School of Engineering and Applied Science, University of Pennsylvania.

Technical Description of the ENIAC

The ENIAC was divided into thirty autonomous units, twenty of which were called accumulators. Each accumulator was essentially a high-speed ten-digit adding machine that could also store the results of its calculations. The ENIAC was a decimal machine, which meant that each of the ten digits in the accumulators counted from zero (0) through nine (9) using a particular configuration of electronic circuits known as a ring counter. To accelerate certain arithmetic operations the ENIAC also had a multiplier and divider-square rooter. The multiplier employed a resistor matrix to perform one-digit multiplications and was designed with additional control circuitry to multiply successive digits drawn from two accumulators holding the multiplier and multiplicand.

The ENIAC was controlled through a train of electronic pulses. Each unit of the ENIAC was capable of issuing a control pulse that would initiate computation in one or more of the other units. This meant that a "computer program" on the ENIAC consisted principally of manually wiring the different units of the machine so that they would perform their operations in the desired sequence. A typical program on the ENIAC thus consisted of a nest of wires interconnecting the various units of the machine. Special wiring trays gave some semblance of order to these wires, but programming the ENIAC was nevertheless a difficult affair.

The task was somewhat simplified by one unit known as the Master Programmer, designed to perform nested loops (the FOR I=1 to 25 instruction in modern programming languages). Incidentally, because the various units of the ENIAC could operate simultaneously, the ENIAC could perform calculations in parallel. ENIAC programmers tended to avoid this use because the impressive but limited reliability of the ENIAC favored the use of as few units as possible for a given application.

Some time during the ENIAC's development, the project's engineers and mathematicians (possibly including its female programmers) discovered that with some minor modifications they could perform what would be considered a conditional branchthe IF-THEN statement in modern programming languages. Those associated with the ENIAC had called this "magnitude discrimination." Partly by chance, the control signals on the ENIAC were essentially identical to the data signals, both of which typically were 2 usec pulses placed at ten usec intervals. By connecting one of the data lines of an accumulator into the control line of another, the ENIAC's operations could, in principle, be controlled based on the content of its data (technically known as data-sensitive operations). Certain aspects in the machine's design made necessary a slightly more complicated implementation. Nevertheless, the ENIAC was probably the first electronic machine to support the conditional branch instruction.

Two women wiring the right side of the ENIAC with a new program (U.S. Army photo, from archives of the ARL Technical Library, courtesy of Mike Muuss).
Two women wiring the right side of the ENIAC with a new program
(U.S. Army photo, from archives of the ARL Technical Library, courtesy of Mike Muuss).

 

The Atanasoff Controversy

Four panels of ENIAC, with Betty Jennings and Frances Bilas (right) arranging the program settings on the master programmer, 1946.
Four panels of ENIAC, with Betty Jennings and Frances Bilas (right)
arranging the program settings on the master programmer, 1946.

 

Two controversies serve as counterpoints to the story of John Mauchly and Pres Eckert and the invention of the ENIAC computer. The first of these concerned the contributions of an Iowa State College professor, John V. Atanasoff, who had designed and built an electronic computing device between 1937 and 1942 with the assistance of his graduate student, Clifford Berry. While there are some doubts as to whether the Atanasoff-Berry Computer (ABC) was ever fully operational, Mauchly visited Atanasoff during the summer of 1941 and had a close look at the machine. The controversy has been over the extent to which Mauchly borrowed Atanasoff's ideas, and whether Atanasoff was the true inventor of the modern electronic computer.

Recognition for invention is highly prized among scientists and academic engineers, whose rewards tend to be more intangible than those of their counterparts in industry. Presper Eckert has been more fortunate than Mauchly in this regard, because his reputation is based on his contributions to the engineering work involved in developing the ENIAC computer. The material artifact itself stood as a demonstration of the superb engineering that had produced an operational large-scale electronic computer. As the principal architect during the early design work on the ENIAC, Mauchly could only rest his claims on the design contributions that he had made to the project. The invisibility of design work has made it possible for others to question from where Mauchly had derived his ideas.

There is actually little doubt that Mauchly was inspired by Atanasoff's work. In 1941 Atanasoff knew more about basic elements of electronic computation than Mauchly and openly shared this knowledge. The ABC, with its several hundred vacuum tubes, represented one of the most complicated electronic circuits at the time, and Mauchly, with his then very limited experience, would have been impressed by its design. Still, the ABC had been designed as a special purpose computer designed only to solve large systems of linear equations. Certain aspects of its design also precluded the ABC from computing at truly electronic speeds. Upon arriving at the Moore School, Mauchly gained access to many other sources of ideas not the least of which was the concept of ganged adding machines proposed by the faculty member Irven Travis. The ENIAC was, in other words, a combination of many different design ideas. Mauchly may have continued to draw ideas from Atanasoff's further reflections on electronic computing, but it was ultimately Mauchly who, working with Eckert, designed the first general- purpose electronic computer. Whether Mauchly gave credit to Atanasoff's contributions remains a separate historical question.

Further reading:
The John Vincent Atanasoff Archive - Dept. of Computer Science, Iowa State University.

The Atanasoff Controversy

Four panels of ENIAC, with Betty Jennings and Frances Bilas (right) arranging the program settings on the master programmer, 1946.
Four panels of ENIAC, with Betty Jennings and Frances Bilas (right)
arranging the program settings on the master programmer, 1946.

 

Two controversies serve as counterpoints to the story of John Mauchly and Pres Eckert and the invention of the ENIAC computer. The first of these concerned the contributions of an Iowa State College professor, John V. Atanasoff, who had designed and built an electronic computing device between 1937 and 1942 with the assistance of his graduate student, Clifford Berry. While there are some doubts as to whether the Atanasoff-Berry Computer (ABC) was ever fully operational, Mauchly visited Atanasoff during the summer of 1941 and had a close look at the machine. The controversy has been over the extent to which Mauchly borrowed Atanasoff's ideas, and whether Atanasoff was the true inventor of the modern electronic computer.

Recognition for invention is highly prized among scientists and academic engineers, whose rewards tend to be more intangible than those of their counterparts in industry. Presper Eckert has been more fortunate than Mauchly in this regard, because his reputation is based on his contributions to the engineering work involved in developing the ENIAC computer. The material artifact itself stood as a demonstration of the superb engineering that had produced an operational large-scale electronic computer. As the principal architect during the early design work on the ENIAC, Mauchly could only rest his claims on the design contributions that he had made to the project. The invisibility of design work has made it possible for others to question from where Mauchly had derived his ideas.

There is actually little doubt that Mauchly was inspired by Atanasoff's work. In 1941 Atanasoff knew more about basic elements of electronic computation than Mauchly and openly shared this knowledge. The ABC, with its several hundred vacuum tubes, represented one of the most complicated electronic circuits at the time, and Mauchly, with his then very limited experience, would have been impressed by its design. Still, the ABC had been designed as a special purpose computer designed only to solve large systems of linear equations. Certain aspects of its design also precluded the ABC from computing at truly electronic speeds. Upon arriving at the Moore School, Mauchly gained access to many other sources of ideas not the least of which was the concept of ganged adding machines proposed by the faculty member Irven Travis. The ENIAC was, in other words, a combination of many different design ideas. Mauchly may have continued to draw ideas from Atanasoff's further reflections on electronic computing, but it was ultimately Mauchly who, working with Eckert, designed the first general- purpose electronic computer. Whether Mauchly gave credit to Atanasoff's contributions remains a separate historical question.

Further reading:
The John Vincent Atanasoff Archive - Dept. of Computer Science, Iowa State University.

The EDVAC Design

Photograph of EDVAC, ca. 1948.
Photograph of EDVAC, ca. 1948.

The fact that the ENIAC was such a revolutionary machine contributed to the second controversy that has marked its historythe development of the "stored program concept." By no means did the ENIAC have all of the architectural features of a modern computer: it was a wartime project, and the exigencies of doing something quickly justified a straight-forward design. But this contingency meant that all of the groups who subsequently took an interest in the ENIAC could propose improvements to the machine, thereby fueling priority disputes over who first came up with a particular concept.

By the spring of 1944 it was clear to many people who had been working on the ENIAC that there were ways to improve its method of operation. Foremost among these new design ideas were methods for simplifying the process of programming and wiring the machine. Realizing this fact well before the ENIAC was operational, Mauchly, Eckert, and other members of the project were already thinking of mechanisms that would simplify programming procedures in a new machine. They included the idea of storing programs within some special mechanism. The prospects of building this improved machine materialized when the Bureau of Ordnance issued a follow-on contract for the EDVAC computer.

It was the highly skilled mathematician, John von Neumann, who produced the best formal description of a stored program computer. During the fall of 1944 von Neumann took time off from his work at the Institute for Advanced Studies in Princeton, New Jersey and the Los Alamos Project to take part in the Moore School discussions regarding the EDVAC design. No official reports or minutes came out of these joint discussions, making issues of credit very difficult to resolve. Instead, Von Neumann independently drafted a report titled the "First Draft Report of the Edvac Design." As a draft document merely reflecting his current thoughts, von Neumann had not attempted to attribute or resolve issues of credit. But Herman Goldstine had given the document wide circulation, which had the unfortunate (or fortunate) result of placing the knowledge in the public domain.

The controversy here reflects, in part, the different cultures of electrical engineers and mathematicians. Whereas electrical engineers tend not to publish their ideas before they turn them into concrete inventions, mathematicians often circulate their ideas amongst colleagues even before they are ready to release them in a publication. Both sides failed to appreciate the different conventions of their respective fields, fueling the priority disputes that ensued.

Further reading:
John von Neumann - J. A. N. Lee, Virginia Tech University

 

The ENIAC

The initiating and cycling units of ENIAC, 1946. The picture on the oscilloscope shows one of the fundamental electrical signals transmitted to all units of the machine. The bulk of the neons above the scope correspond to the twenty different parts of an addition. Each of the parts represent 1/100,000 of a second.
The initiating and cycling units of ENIAC, 1946.
The picture on the oscilloscope shows one of the fundamental
electrical signals transmitted to all units of the machine. The bulk of
the neons above the scope correspond to the twenty
different parts of an addition. Each of the parts
represent 1/100,000 of a second.

The ENIAC was a large-scale, general purpose digital electronic computer. Built out of some 17,468 electronic vacuum tubes, ENIAC was in its time the largest single electronic apparatus in the world. There were two fundamental technical innovations in the ENIAC. The first had to do with combining very diverse technical components and design ideas into a single system that could perform 5,000 additions and 300 multiplications per second. Although slow by today's standardscurrent microprocessors perform 100 million additions per secondthis was two to three orders of magnitude (100 to 1,000 times) faster than existing mechanical computers or calculators. 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.

The second, and equally impressive, technical achievement was the machine's reliability. Many others working on large-scale precision machinery, such as electronic fire control systems and differential analyzers, considered the possibility of electronic computation before either Mauchly or Atanasoff. These scientists, however, rejected digital electronic computing, because they felt that a system large enough to do useful computations would require too many vacuum tubes to provide reliable operation. As the main project engineer for the ENIAC, J. Presper Eckert proved to be an outstanding engineer who overcame the most difficult technical challenges in building the ENIAC. The rigorous vacuum tube reliability studies that he oversaw and the cautious reliability design methods adopted by the entire ENIAC project team made it possible to operate the ENIAC, with all of its vacuum tubes, within a comfortable margin of reliability.

The ENIAC was officially unveiled to the public on Valentine's Day, 14 February 1946. Press releases from the War Department and articles that appeared in popular magazines, such as Newsweek, attest to the widespread attention that ENIAC received upon its public dedication.

 

The UNIVAC & the Legacy of the ENIAC

Illustration from cover of Remington Rand brochure on UNIVAC, n.d.
Cover illustration from Remington Rand brochure on UNIVAC, n.d.

The ENIAC's legacy was larger than just the UNIVAC computer built by the Eckert- Mauchly Computer Corporation. The SEAC, ILLIAC, Whirlwind and MANIACas well as von Neumann's computer built at the Institute for Advanced Studies in Princeton, New Jerseywere among the one-of-a-kind computers that succeeded the ENIAC. Seeing the potential in electronic digital computation, other private firms, including Engineering Research Associates and IBM, soon entered into the business of digital electronic computers. The backdrop of this panel recapitulates the technical lineage that led into the ENIAC and lists the series of computer systems that emerged in its wake.

The development of a commercial computer proved too difficult for a start-up company. Although Mauchly and Eckert could produce an experimental machine in the confines of a laboratory, a standard commercial system run by trained operators rather than research engineers required further improvements in design and reliability. Problems concerning military security and the hostile attitude of certain influential academic advisors to the military made Eckert and Mauchly's job more difficult. Ultimately it was the cost of developing a commercial computer that led Eckert and Mauchly to sell their company to Remington Rand in February of 1950.

The first UNIVAC computer was delivered to the Census Bureau in June 1951. Unlike the ENIAC, the UNIVAC processed each digit serially. But its much higher design speed permitted it to add two ten-digit numbers at a rate of almost 100,000 additions per second. Internally, the UNIVAC operated at a clock frequency of 2.25 MHz, which was no mean feat for vacuum tube circuits. The UNIVAC also employed mercury delay-line memories. Delay lines did not allow the computer to access immediately any item data held in its memory, but given the reliability problems of the alternative Cathode Ray Tube (CRT) technology, this was a good technical choice.

Finally, the UNIVAC had placed strong emphasis on its input/output capabilities, being designed specifically for data processing applications such as that of the Census Bureau. In this connection, EMCC had developed a digital magnetic tape recording unit that could deliver data to the UNIVAC at a rate of 40,000 binary digits (bits) per second. For a brief period, Univac had captured a majority of the market for digital electronic computer systems.

Further reading:
Articles on UNIVAC’s history since 1953 - George Gray, Unisys History Newsletter.

The UNIVAC & the Legacy of the ENIAC

Illustration from cover of Remington Rand brochure on UNIVAC, n.d.
Cover illustration from Remington Rand brochure on UNIVAC, n.d.

The ENIAC's legacy was larger than just the UNIVAC computer built by the Eckert- Mauchly Computer Corporation. The SEAC, ILLIAC, Whirlwind and MANIACas well as von Neumann's computer built at the Institute for Advanced Studies in Princeton, New Jerseywere among the one-of-a-kind computers that succeeded the ENIAC. Seeing the potential in electronic digital computation, other private firms, including Engineering Research Associates and IBM, soon entered into the business of digital electronic computers. The backdrop of this panel recapitulates the technical lineage that led into the ENIAC and lists the series of computer systems that emerged in its wake.

The development of a commercial computer proved too difficult for a start-up company. Although Mauchly and Eckert could produce an experimental machine in the confines of a laboratory, a standard commercial system run by trained operators rather than research engineers required further improvements in design and reliability. Problems concerning military security and the hostile attitude of certain influential academic advisors to the military made Eckert and Mauchly's job more difficult. Ultimately it was the cost of developing a commercial computer that led Eckert and Mauchly to sell their company to Remington Rand in February of 1950.

The first UNIVAC computer was delivered to the Census Bureau in June 1951. Unlike the ENIAC, the UNIVAC processed each digit serially. But its much higher design speed permitted it to add two ten-digit numbers at a rate of almost 100,000 additions per second. Internally, the UNIVAC operated at a clock frequency of 2.25 MHz, which was no mean feat for vacuum tube circuits. The UNIVAC also employed mercury delay-line memories. Delay lines did not allow the computer to access immediately any item data held in its memory, but given the reliability problems of the alternative Cathode Ray Tube (CRT) technology, this was a good technical choice.

Finally, the UNIVAC had placed strong emphasis on its input/output capabilities, being designed specifically for data processing applications such as that of the Census Bureau. In this connection, EMCC had developed a digital magnetic tape recording unit that could deliver data to the UNIVAC at a rate of 40,000 binary digits (bits) per second. For a brief period, Univac had captured a majority of the market for digital electronic computer systems.

Further reading:
Articles on UNIVAC’s history since 1953 - George Gray, Unisys History Newsletter.

The UNIVAC & the Legacy of the ENIAC

Illustration from cover of Remington Rand brochure on UNIVAC, n.d.
Cover illustration from Remington Rand brochure on UNIVAC, n.d.

The ENIAC's legacy was larger than just the UNIVAC computer built by the Eckert- Mauchly Computer Corporation. The SEAC, ILLIAC, Whirlwind and MANIACas well as von Neumann's computer built at the Institute for Advanced Studies in Princeton, New Jerseywere among the one-of-a-kind computers that succeeded the ENIAC. Seeing the potential in electronic digital computation, other private firms, including Engineering Research Associates and IBM, soon entered into the business of digital electronic computers. The backdrop of this panel recapitulates the technical lineage that led into the ENIAC and lists the series of computer systems that emerged in its wake.

The development of a commercial computer proved too difficult for a start-up company. Although Mauchly and Eckert could produce an experimental machine in the confines of a laboratory, a standard commercial system run by trained operators rather than research engineers required further improvements in design and reliability. Problems concerning military security and the hostile attitude of certain influential academic advisors to the military made Eckert and Mauchly's job more difficult. Ultimately it was the cost of developing a commercial computer that led Eckert and Mauchly to sell their company to Remington Rand in February of 1950.

The first UNIVAC computer was delivered to the Census Bureau in June 1951. Unlike the ENIAC, the UNIVAC processed each digit serially. But its much higher design speed permitted it to add two ten-digit numbers at a rate of almost 100,000 additions per second. Internally, the UNIVAC operated at a clock frequency of 2.25 MHz, which was no mean feat for vacuum tube circuits. The UNIVAC also employed mercury delay-line memories. Delay lines did not allow the computer to access immediately any item data held in its memory, but given the reliability problems of the alternative Cathode Ray Tube (CRT) technology, this was a good technical choice.

Finally, the UNIVAC had placed strong emphasis on its input/output capabilities, being designed specifically for data processing applications such as that of the Census Bureau. In this connection, EMCC had developed a digital magnetic tape recording unit that could deliver data to the UNIVAC at a rate of 40,000 binary digits (bits) per second. For a brief period, Univac had captured a majority of the market for digital electronic computer systems.

Further reading:
Articles on UNIVAC’s history since 1953 - George Gray, Unisys History Newsletter.

The UNIVAC & the Legacy of the ENIAC

Illustration from cover of Remington Rand brochure on UNIVAC, n.d.
Cover illustration from Remington Rand brochure on UNIVAC, n.d.

The ENIAC's legacy was larger than just the UNIVAC computer built by the Eckert- Mauchly Computer Corporation. The SEAC, ILLIAC, Whirlwind and MANIACas well as von Neumann's computer built at the Institute for Advanced Studies in Princeton, New Jerseywere among the one-of-a-kind computers that succeeded the ENIAC. Seeing the potential in electronic digital computation, other private firms, including Engineering Research Associates and IBM, soon entered into the business of digital electronic computers. The backdrop of this panel recapitulates the technical lineage that led into the ENIAC and lists the series of computer systems that emerged in its wake.

The development of a commercial computer proved too difficult for a start-up company. Although Mauchly and Eckert could produce an experimental machine in the confines of a laboratory, a standard commercial system run by trained operators rather than research engineers required further improvements in design and reliability. Problems concerning military security and the hostile attitude of certain influential academic advisors to the military made Eckert and Mauchly's job more difficult. Ultimately it was the cost of developing a commercial computer that led Eckert and Mauchly to sell their company to Remington Rand in February of 1950.

The first UNIVAC computer was delivered to the Census Bureau in June 1951. Unlike the ENIAC, the UNIVAC processed each digit serially. But its much higher design speed permitted it to add two ten-digit numbers at a rate of almost 100,000 additions per second. Internally, the UNIVAC operated at a clock frequency of 2.25 MHz, which was no mean feat for vacuum tube circuits. The UNIVAC also employed mercury delay-line memories. Delay lines did not allow the computer to access immediately any item data held in its memory, but given the reliability problems of the alternative Cathode Ray Tube (CRT) technology, this was a good technical choice.

Finally, the UNIVAC had placed strong emphasis on its input/output capabilities, being designed specifically for data processing applications such as that of the Census Bureau. In this connection, EMCC had developed a digital magnetic tape recording unit that could deliver data to the UNIVAC at a rate of 40,000 binary digits (bits) per second. For a brief period, Univac had captured a majority of the market for digital electronic computer systems.

Further reading:
Articles on UNIVAC’s history since 1953 - George Gray, Unisys History Newsletter.

World War II & the Moore School

Page discussing use of differential analyzer in Gilbert Bliss, Mathematics for Exterior Ballistics, 1944.
Page discussing use of differential analyzer in
Gilbert Bliss, Mathematics for Exterior Ballistics, 1944.

 

Few aspects of life remained untouched by World War II. Even before the attack on Pearl Harbor, the United States had begun to mobilize the nation's scientific and engineering resources, particularly through the work of the National Defense Research Committee (NDRC). But the NDRC was not the only vehicle for science mobilization. At the Moore School change resulted more from the military training programs established for the U.S. Army and Navy and through several secret wartime projects supported by the U.S. Army Ordnance Department's Ballistics Research Laboratory. The Ballistics Research Laboratory (BRL) was charged with producing firing tables in conjunction with the ever-changing field artillery that were being used in the war. This need had brought the contract for the Moore School differential analyzer, a mechanical analog calculating engine that had preceded the ENIAC work. Such efforts created a demand for additional faculty, and when Mauchly completed his summer training course, he was offered a position as an adjunct instructor.

The pressing needs of BRL also brought to the Moore School a team of skilled women who operated desk-top calculating machines to produce manually firing tables. Electrical Engineering had traditionally been a male discipline, and the arrival of women raised some waves, particularly among the School's undergraduates. However, these women, some of whom were hired directly by the School and others who were assigned out of the Army's Women's Auxiliary Corps (WACs), were generally older than the students. To make matters worse, many of them already held mathematics degrees. As a contemporary student comic strip, "Moore School Mike" depicts, the self-image of engineers was as much about their awkwardness as their sexual desires. This and material within Mauchly's own papers reveal the very gendered nature of engineering workplaces during World War II.

Much of Mauchly's daily life was occupied with both war research and his teaching duties. He took over some of the basic electrical engineering courses opened up by faculty members who had been reassigned to war research. At the same time, he was assigned to a U.S. Army Signal Corps project to calculate antenna radiation patterns for radar use. In conjunction with this project, Mauchly himself had hired a team of mostly female mathematicians to perform manual calculations. During his private time Mauchly studied cryptography, which also dealt with statistical quantities. All of this work extended his exposure to complicated calculations, which only increased his interests in electronic computation.

Further reading:
Electronic Computers Within the Ordnance Corps - Karl Kempf, Historical Officer, Aberdeen Proving Ground, MD, November 1961.
History of Computing Information - Mike Muuss, Ballistic Research Laboratory.
Past Notable Women of Computing & Mathematics - The Ada Project, Yale University.

World War II & the Moore School

Page discussing use of differential analyzer in Gilbert Bliss, Mathematics for Exterior Ballistics, 1944.
Page discussing use of differential analyzer in
Gilbert Bliss, Mathematics for Exterior Ballistics, 1944.

 

Few aspects of life remained untouched by World War II. Even before the attack on Pearl Harbor, the United States had begun to mobilize the nation's scientific and engineering resources, particularly through the work of the National Defense Research Committee (NDRC). But the NDRC was not the only vehicle for science mobilization. At the Moore School change resulted more from the military training programs established for the U.S. Army and Navy and through several secret wartime projects supported by the U.S. Army Ordnance Department's Ballistics Research Laboratory. The Ballistics Research Laboratory (BRL) was charged with producing firing tables in conjunction with the ever-changing field artillery that were being used in the war. This need had brought the contract for the Moore School differential analyzer, a mechanical analog calculating engine that had preceded the ENIAC work. Such efforts created a demand for additional faculty, and when Mauchly completed his summer training course, he was offered a position as an adjunct instructor.

The pressing needs of BRL also brought to the Moore School a team of skilled women who operated desk-top calculating machines to produce manually firing tables. Electrical Engineering had traditionally been a male discipline, and the arrival of women raised some waves, particularly among the School's undergraduates. However, these women, some of whom were hired directly by the School and others who were assigned out of the Army's Women's Auxiliary Corps (WACs), were generally older than the students. To make matters worse, many of them already held mathematics degrees. As a contemporary student comic strip, "Moore School Mike" depicts, the self-image of engineers was as much about their awkwardness as their sexual desires. This and material within Mauchly's own papers reveal the very gendered nature of engineering workplaces during World War II.

Much of Mauchly's daily life was occupied with both war research and his teaching duties. He took over some of the basic electrical engineering courses opened up by faculty members who had been reassigned to war research. At the same time, he was assigned to a U.S. Army Signal Corps project to calculate antenna radiation patterns for radar use. In conjunction with this project, Mauchly himself had hired a team of mostly female mathematicians to perform manual calculations. During his private time Mauchly studied cryptography, which also dealt with statistical quantities. All of this work extended his exposure to complicated calculations, which only increased his interests in electronic computation.

Further reading:
Electronic Computers Within the Ordnance Corps - Karl Kempf, Historical Officer, Aberdeen Proving Ground, MD, November 1961.
History of Computing Information - Mike Muuss, Ballistic Research Laboratory.
Past Notable Women of Computing & Mathematics - The Ada Project, Yale University.

World War II & the Moore School

Page discussing use of differential analyzer in Gilbert Bliss, Mathematics for Exterior Ballistics, 1944.
Page discussing use of differential analyzer in
Gilbert Bliss, Mathematics for Exterior Ballistics, 1944.

 

Few aspects of life remained untouched by World War II. Even before the attack on Pearl Harbor, the United States had begun to mobilize the nation's scientific and engineering resources, particularly through the work of the National Defense Research Committee (NDRC). But the NDRC was not the only vehicle for science mobilization. At the Moore School change resulted more from the military training programs established for the U.S. Army and Navy and through several secret wartime projects supported by the U.S. Army Ordnance Department's Ballistics Research Laboratory. The Ballistics Research Laboratory (BRL) was charged with producing firing tables in conjunction with the ever-changing field artillery that were being used in the war. This need had brought the contract for the Moore School differential analyzer, a mechanical analog calculating engine that had preceded the ENIAC work. Such efforts created a demand for additional faculty, and when Mauchly completed his summer training course, he was offered a position as an adjunct instructor.

The pressing needs of BRL also brought to the Moore School a team of skilled women who operated desk-top calculating machines to produce manually firing tables. Electrical Engineering had traditionally been a male discipline, and the arrival of women raised some waves, particularly among the School's undergraduates. However, these women, some of whom were hired directly by the School and others who were assigned out of the Army's Women's Auxiliary Corps (WACs), were generally older than the students. To make matters worse, many of them already held mathematics degrees. As a contemporary student comic strip, "Moore School Mike" depicts, the self-image of engineers was as much about their awkwardness as their sexual desires. This and material within Mauchly's own papers reveal the very gendered nature of engineering workplaces during World War II.

Much of Mauchly's daily life was occupied with both war research and his teaching duties. He took over some of the basic electrical engineering courses opened up by faculty members who had been reassigned to war research. At the same time, he was assigned to a U.S. Army Signal Corps project to calculate antenna radiation patterns for radar use. In conjunction with this project, Mauchly himself had hired a team of mostly female mathematicians to perform manual calculations. During his private time Mauchly studied cryptography, which also dealt with statistical quantities. All of this work extended his exposure to complicated calculations, which only increased his interests in electronic computation.

Further reading:
Electronic Computers Within the Ordnance Corps - Karl Kempf, Historical Officer, Aberdeen Proving Ground, MD, November 1961.
History of Computing Information - Mike Muuss, Ballistic Research Laboratory.
Past Notable Women of Computing & Mathematics - The Ada Project, Yale University.

Selected bibliography

Contributors