Текст книги "The Innovators: How a Group of Inventors, Hackers, Geniuses, and Geeks Created the Digital Revolution"

Автор книги: Walter Isaacson

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Текущая страница: 5 (всего у книги 42 страниц)

George Stibitz (1904–95) circa 1945.

Konrad Zuse (1910–95) with the Z4 computer in 1944.

John Atanasoff (1903–95) at Iowa State, circa 1940.

Reconstruction of Atanasoff’s computer.

Once he had settled on the memory unit, Atanasoff turned his attention to how to construct the arithmetic and logic unit, which he called the “computing mechanism.” He decided it should be fully electronic; that meant using vacuum tubes, even though they were expensive. The tubes would act as on-off switches to perform the function of logic gates in a circuit that could add, subtract, and perform any Boolean function.

That raised a theoretical math issue of the type he had loved since he was a boy: Should his digital system be decimal or binary or rely on some other numerical base? A true enthusiast for number systems, Atanasoff explored many options. “For a short time the base one-hundred was thought to have some promise,” he wrote in an unpublished paper. “This same calculation showed that the base that theoretically gives the highest speed of calculation is e, the natural base.”³¹ But, balancing theory with practicality, he finally settled on base-2, the binary system. By late 1937, these and other ideas were jangling around in his head, a “hodgepodge” of concepts that wouldn’t “jell.”

Atanasoff loved cars; he liked to buy, if he could, a new one each year, and in December 1937, he had a new Ford with a powerful V8 engine. To relax his mind, he took it for a late-night spin for what would become a noteworthy moment in the history of computing:

One night in the winter of 1937 my whole body was in torment from trying to solve the problems of the machine. I got in my car and drove at high speeds for a long while so I could control my emotions. It was my habit to do this for a few miles: I could gain control of myself by concentrating on driving. But that night I was excessively tormented, and I kept on going until I had crossed the Mississippi River into Illinois and was 189 miles from where I started.³²

He turned off the highway and pulled into a roadhouse tavern. At least in Illinois, unlike in Iowa, he could buy a drink, and he ordered himself a bourbon and soda, then another. “I realized that I was no longer so nervous and my thoughts turned again to computing machines,” he recalled. “I don’t know why my mind worked then when it had not worked previously, but things seemed to be good and cool and quiet.” The waitress was inattentive, so Atanasoff got to process his problem undisturbed.³³

He sketched out his ideas on a paper napkin, then began to sort through some practical questions. The most important was how to replenish the charges in the condensers, which would otherwise drain after a minute or two. He came up with the idea of putting them on rotating cylinder drums, about the size of 46-ounce cans of V8 juice, so they would come into contact once a second with brushlike wires and have their charges refreshed. “During this evening in the tavern, I generated within my mind the possibility of the regenerative memory,” he declared. “I called it ‘jogging’ at that time.” With each turn of the rotating cylinder, the wires would jog the memory of the condensers and, when necessary, retrieve data from the condensers and store new data. He also came up with an architecture that would take numbers from two different cylinders of condensers, then use the vacuum-tube circuit to add or subtract them and put the result into memory. After a few hours of figuring everything out, he recalled, “I got in my car and drove home at a slower rate.”³⁴

By May 1939, Atanasoff was ready to begin construction of a prototype. He needed an assistant, preferably a graduate student with engineering experience. “I have your man,” a friend on the faculty told him one day. Thus he struck up a partnership with another son of a self-taught electrical engineer, Clifford Berry.³⁵

The machine was designed and hard-wired with a single purpose: solving simultaneous linear equations. It could handle up to twenty-nine variables. With each step, Atanasoff’s machine would process two equations and eliminate one of the variables, then print the resulting equations on 8 x 11 binary punch cards. This set of cards with the simpler equation would then be fed back into the machine for the process to begin anew, eliminating yet another variable. The process required a bit of time. The machine would (if they could get it to work properly) take almost a week to complete a set of twenty-nine equations. Still, humans doing the same process on desk calculators would require at least ten weeks.

Atanasoff demonstrated a prototype at the end of 1939 and, hoping to get funding to build a full-scale machine, typed up a thirty-five-page proposal, using carbon paper to make a few copies. “It is the main purpose of this paper to present a description and exposition of a computing machine which has been designed principally for the solution of large systems of linear algebraic equations,” he began. As if to fend off criticism that this was a limited purpose for a big machine, Atanasoff specified a long list of problems that required solving such equations: “curve fitting . . . vibrational problems . . . electrical circuit analysis . . . elastic structures.” He concluded with a detailed list of proposed expenditures, which added up to the grand sum of $5,330, which he ended up getting from a private foundation.³⁶ Then he sent one of the carbon copies of his proposal to a Chicago patent lawyer retained by Iowa State, who, in a dereliction of duty that would spawn decades of historical and legal controversy, never got around to filing for any patents.

By September 1942 Atanasoff’s full-scale model was almost finished. It was the size of a desk and contained close to three hundred vacuum tubes. There was, however, a problem: the mechanism for using sparks to burn holes in the punch cards never worked properly, and there were no teams of machinists and engineers at Iowa State he could turn to for help.

At that point, work stopped. Atanasoff was drafted into the Navy and sent to its ordnance laboratory in Washington, DC, where he worked on acoustic mines and later attended the atomic bomb tests at Bikini Atoll. Shifting his focus from computers to ordnance engineering, he remained an inventor, earning thirty patents, including on a minesweeping device. But his Chicago lawyer never applied for patents on his computer.

Atanasoff’s computer could have been an important milestone, but it was, both literally and figuratively, relegated to the dustbin of history. The almost-working machine was put into storage in the basement of the physics building at Iowa State, and a few years later no one seemed to remember what it did. When the space was needed for other uses in 1948, a graduate student dismantled it, not realizing what it was, and discarded most of the parts.³⁷ Many early histories of the computer age do not even mention Atanasoff.

Even if it had worked properly, his machine had limitations. The vacuum-tube circuit made lightning-fast calculations, but the mechanically rotated memory units slowed down the process enormously. So did the system for burning holes in the punch cards, even when it worked. In order to be truly fast, modern computers would have to be all-electronic, not just partly. Nor was Atanasoff’s model programmable. It was geared to do just one thing: solve linear equations.

Atanasoff’s enduring romantic appeal is that he was a lone tinkerer in a basement, with only his young sidekick Clifford Berry for a companion. But his tale is evidence that we shouldn’t in fact romanticize such loners. Like Babbage, who also toiled in his own little workshop with just an assistant, Atanasoff never got his machine to be fully functional. Had he been at Bell Labs, amid swarms of technicians and engineers and repairmen, or at a big research university, a solution would likely have been found for fixing the card reader as well as the other balky parts of his contraption. Plus, when Atanasoff was called away to the Navy in 1942, there would have been team members left behind to put on the finishing touches, or at least to remember what was being built.

What saved Atanasoff from being a forgotten historical footnote is somewhat ironic, given the resentment he later felt about the event. It was a visit that he had in June 1941 from one of those people who, instead of toiling in isolation, loved visiting places and snatching up ideas and working with teams of people. John Mauchly’s trip to Iowa would later be the subject of costly lawsuits, bitter accusations, and dueling historical narratives. But it is what saved Atanasoff from obscurity and moved the course of computer history forward.

JOHN MAUCHLY

In the early twentieth century, the United States developed, as Britain had earlier, a class of gentleman scientists who congregated at wood-paneled explorers’ clubs and other rarefied institutes, where they enjoyed sharing ideas, listening to lectures, and collaborating on projects. John Mauchly was raised in that realm. His father, a physicist, was a research chief in the Department of Terrestrial Magnetism at the Washington-based Carnegie Institution, the nation’s foremost foundation for promoting the advance and sharing of research. His specialty was recording electrical conditions in the atmosphere and relating them to the weather, a collegial endeavor that involved coordinating researchers from Greenland to Peru.³⁸

Growing up in the Washington suburb of Chevy Chase, John was exposed to the area’s growing scientific community. “Chevy Chase seemed to have practically all the scientists in Washington,” he boasted. “The director of the Weights and Measures Division of the Bureau of Standards lived near us. So did the director of its Radio Division.” The head of the Smithsonian was also a neighbor. John spent many weekends using a desktop adding machine to do calculations for his dad, and he developed a passion for data-driven meteorology. He also loved electrical circuits. With his young friends in his neighborhood, he laid intercom wires that connected their homes and built remote-control devices to launch fireworks for parties. “When I pressed a button, the fireworks would go off 50 feet away.” At age fourteen he was earning money helping people in the neighborhood fix faulty wiring in their homes.³⁹

While an undergraduate at Johns Hopkins University, Mauchly enrolled in a program for exceptional undergraduates to leap directly into a PhD program in physics. He did his thesis on light band spectroscopy because it combined beauty, experiments, and theory. “You had to know some theory to figure out what the band spectra was all about, but you couldn’t do it unless you had the experimental photographs of that spectrum, and who’s going to get it for you?” he said. “Nobody but you. So I got plenty of training in glass blowing, and drawing vacuums, finding the leaks etc.”⁴⁰

Mauchly had an engaging personality and a wonderful ability (and desire) to explain things, so it was natural that he would become a professor. Such posts were hard to come by in the Depression, but he managed to land one at Ursinus College, an hour’s drive northwest from Philadelphia. “I was the only person teaching physics there,” he said.⁴¹

An essential component of Mauchly’s personality was that he liked to share ideas—usually with a broad grin and a sense of flair—which made him a wildly popular teacher. “He loved to talk and seemed to develop many of his ideas in the give-and-take of conversation,” recalled a colleague. “John loved social occasions, liked to eat good food and drink good liquor. He liked women, attractive young people, the intelligent and the unusual.”⁴² It was dangerous to ask him a question, because he could discourse earnestly and passionately about almost anything, from theater to literature to physics.

In front of a class he played the showman. To explain momentum he would whirl around with his arms flung out and then pulled in, and to describe the concept of action and reaction he would stand on a homemade skateboard and lurch back and forth, a trick that one year resulted in his falling and breaking an arm. People used to drive miles to hear his end-of-term pre-Christmas lecture, which the college moved to its biggest auditorium to accommodate all the visitors. In it he explained how spectrography and other tools of physics could be used to determine what was inside a package without unwrapping it. According to his wife, “He measured it. He weighed it. He submerged it in water. He poked it with a long needle.”⁴³

Reflecting his boyhood fascination with meteorology, Mauchly’s research focus in the early 1930s was on whether long-range weather patterns were related to solar flares, sunspots, and the rotation of the sun. The scientists at the Carnegie Institution and the U.S. Weather Bureau gave him twenty years of daily data from two hundred stations, and he set to work calculating correlations. He was able (this being the Depression) to buy used desk calculators cheaply from ailing banks and to hire a group of young people, through the New Deal’s National Youth Administration, to do computations at fifty cents an hour.⁴⁴

Like others whose work required tedious calculations, Mauchly yearned to invent a machine to do them. With his gregarious style, he set about finding out what others were doing and, in the tradition of great innovators, putting together a variety of ideas. In the IBM pavilion at the 1939 New York World’s Fair, he saw an electric calculator that used punch cards, but he realized that relying on cards would be too slow, given the amount of data he had to crunch. He also saw an encryption machine that used vacuum tubes to code messages. Might the tubes be used for other logical circuits? He took his students on a field trip to Swarthmore College to see counting devices that used circuits made with vacuum tubes to measure bursts of cosmic-ray ionization.⁴⁵ He also took a night course in electronics and began to experiment with his own hand-wired vacuum-tube circuits to see what else they might do.

At a conference at Dartmouth College in September 1940, Mauchly saw a demonstration by George Stibitz of the Complex Number Calculator he had built at Bell Labs. What made the demonstration exciting was that Stibitz’s computer was sitting at Bell’s building in lower Manhattan, transmitting data over a Teletype line. It was the first computer to be used remotely. For three hours it solved problems submitted by the audience, taking about a minute for each. Among those at the demonstration was Norbert Wiener, a pioneer of information systems, who tried to stump Stibitz’s machine by asking it to divide a number by zero. The machine didn’t fall for the trap. Also present was John von Neumann, the Hungarian polymath who was soon to play a major role with Mauchly in the development of computers.⁴⁶

When he decided to build a vacuum-tube computer of his own, Mauchly did what good innovators properly do: he drew upon all of the information he had picked up from his travels. Because Ursinus had no research budget, Mauchly paid for tubes out of his own pocket and tried to cadge them from manufacturers. He wrote the Supreme Instruments Corp. asking for components and declaring, “I am intending to construct an electrical calculating machine.”⁴⁷ He discovered during a visit to RCA that neon tubes could also be used as switches; they were slower but cheaper than vacuum tubes, and he bought a supply at eight cents apiece. “Before November 1940,” his wife later said, “Mauchly had successfully tested certain components of his proposed computer and convinced himself that it was possible to build a cheap, reliable digital device using only electronic elements.” This occurred, she insisted, before he had even heard of Atanasoff.⁴⁸

In late 1940 he confided in some friends that he hoped to pull together all of this information to make a digital electronic computer. “We are now considering construction of an electrical computing machine,” he wrote that November to a meteorologist he had worked with. “The machine would perform its operations in about 1/200th second, using vacuum tube relays.”⁴⁹ Even though he was collaborative and picking up information from many people, he began to exhibit a competitive urge to be the first to make a new type of computer. He wrote a former student in December, “For your own private information, I expect to have, in a year or so, when I can get the stuff and put it together, an electronic computing machine. . . . Keep this dark, since I haven’t the equipment this year to carry it out and I would like to ‘be the first.’ ”⁵⁰

That month, December 1940, Mauchly happened to meet Atanasoff, setting off a series of events followed by years of disputes over Mauchly’s propensity to gather information from different sources and his desire to “be the first.” Atanasoff was attending a meeting at the University of Pennsylvania, and he dropped by a session at which Mauchly proclaimed his hope of building a machine to analyze weather data. Afterward Atanasoff came up to say that he had been building an electronic calculator at Iowa State. Mauchly jotted on his conference program a note that Atanasoff claimed to have devised a machine that could process and store data at a cost of only $2 per digit. (Atanasoff’s machine could handle three thousand digits and cost about $6,000.) Mauchly was amazed. He estimated that the cost of a vacuum-tube computer would be almost $13 per digit. He said he would love to see how it was done, and Atanasoff invited him to come to Iowa.

Throughout the first half of 1941, Mauchly corresponded with Atanasoff and continued to marvel at the low cost he claimed for his machine. “Less than $2 per digit sounds next to impossible, and yet that is what I understood you to say,” he wrote. “Your suggestion about visiting Iowa seemed rather fantastic when first made, but the idea grows on me.” Atanasoff urged him to accept. “As an additional inducement I will explain the $2 per digit business,” he promised.⁵¹

THE MAUCHLY-ATANASOFF VISIT

The fateful visit lasted four days in June 1941.⁵² Mauchly drove from Washington and brought his six-year-old son, Jimmy, arriving late on Friday, June 13, much to the surprise of Atanasoff’s wife, Lura, who had not yet prepared the guest room. “I had to fly around, go to the attic, get extra pillows, and everything,” she later recalled.⁵³ She also made them supper, since the Mauchlys had arrived hungry. The Atanasoffs had three children of their own, but Mauchly seemed to assume that Lura would take care of Jimmy during the visit, so she did, grudgingly. She took a dislike to Mauchly. “I don’t think he’s honest,” she told her husband at one point.⁵⁴

Atanasoff was eager to show off his partly built machine, even as his wife worried that he was being too trusting. “You must be careful until this is patented,” she warned. Nevertheless, Atanasoff took Mauchly, along with Lura and the children, to the physics building basement the next morning, proudly pulling off a sheet to reveal what he and Berry were cobbling together.

Mauchly was impressed by a few things. The use of condensers in the memory unit was ingenious and cost-effective, as was Atanasoff’s method of replenishing their charge every second or so by putting them on rotating cylinders. Mauchly had thought about using condensers instead of more expensive vacuum tubes, and he appreciated how Atanasoff’s method of “jogging their memory” made it workable. That was the secret behind how the machine could be constructed for $2 per digit. After reading Atanasoff’s thirty-five-page memo detailing the machine, and taking notes, he asked if he could take a carbon copy home. That request Atanasoff denied, both because he had no extras to give away (photocopiers hadn’t been invented) and because he was becoming worried that Mauchly was sucking in too much information.⁵⁵

But for the most part, Mauchly was uninspired by what he saw in Ames—or at least that is what he insisted in retrospect. The foremost drawback was that Atanasoff’s machine was not fully electronic but instead relied on the mechanical drums of condensers for memory. That made it inexpensive but also very slow. “I thought his machine was very ingenious, but since it was in part mechanical, involving rotating commutators for switching, it was not by any means what I had in mind,” Mauchly remembered. “I no longer became interested in the details.” Later, in his testimony at the trial over the validity of his patents, Mauchly called the semimechanical nature of Atanasoff’s machine “a rather drastic disappointment” and dismissed it as “a mechanical gadget which uses some electronic tubes in operation.”⁵⁶

The second disappointment, Mauchly contended, was that Atanasoff’s machine was designed for a single purpose and could not be programmed or modified to perform other tasks: “He had not done anything to plan for this machine to be anything but a single set purpose machine and to solve sets of linear equations.”⁵⁷

So Mauchly left Iowa not with a breakthrough concept for how to build a computer but rather with a handful of smaller insights to add to the basket of ideas he had been collecting, consciously and subconsciously, on his visits to conferences and colleges and fairs. “I came to Iowa with much the same attitude that I went to the World’s Fair and other places,” he testified. “Is there something here which would be useful to aid my computations or anyone else’s?”⁵⁸

Like most people, Mauchly gleaned insights from a variety of experiences, conversations, and observations—in his case at Swarthmore, Dartmouth, Bell Labs, RCA, the World’s Fair, Iowa State, and elsewhere—then combined them into ideas he considered his own. “A new idea comes suddenly and in a rather intuitive way,” Einstein once said, “but intuition is nothing but the outcome of earlier intellectual experience.” When people take insights from multiple sources and put them together, it’s natural for them to think that the resulting ideas are their own—as in truth they are. All ideas are born that way. So Mauchly considered his intuitions and thoughts about how to build a computer to be his own rather than a bag of ideas he had stolen from other people. And despite later legal findings, he was for the most part right, insofar as anyone can be right in thinking that his ideas are his own. That is the way the creative process—if not the patent process—works.

Unlike Atanasoff, Mauchly had the opportunity, and the inclination, to collaborate with a team filled with varied talents. As a result, instead of producing a machine that didn’t quite work and was abandoned in a basement, he and his team would go down in history as the inventors of the first electronic general-purpose computer.

As he was preparing to leave Iowa, Mauchly got a piece of pleasant news. He had been accepted into an electronics course at the University of Pennsylvania, one of the many around the country being funded on an emergency basis by the War Department. It was a chance to learn more about using vacuum tubes in electronic circuits, which he was now convinced was the best way to make computers. It also showed the importance of the military in driving innovation in the digital age.

During this ten-week course in the summer of 1941, Mauchly got the chance to work with a version of the MIT Differential Analyzer, the analog computer designed by Vannevar Bush. The experience amped up his interest in building his own computer. It also made him realize that the resources to do so at a place like Penn were far greater than at Ursinus, so he was thrilled to accept an instructor’s position at the university when it was offered at the end of the summer.

Mauchly conveyed the good news in a letter to Atanasoff, which also contained hints of a plan that unnerved the Iowa professor. “A number of different ideas have come to me recently anent computing circuits—some of which are more or less hybrids, combining your methods with other things, and some of which are nothing like your machine,” Mauchly wrote, truthfully. “The question in my mind is this: is there any objection, from your point of view, to my building some sort of computer which incorporates some of the features of your machine?”⁵⁹ It’s hard to tell from the letter, or from the subsequent explanations, depositions, and testimony over the ensuing years, whether Mauchly’s innocent tone was sincere or feigned.