To get ENIAC to change tasks, its handlers had to reset it manually by flipping switches and unplugging thousands of tangled cables. It could take days to rearrange its hardware for a problem that then took just minutes to compute. Inspired by Turing — whose “On Computable Numbers” he constantly recommended to colleagues — von Neumann began to conceptualize the design of a computer controlled by coded instructions stored internally.
To usher in the brave new world of Turing machines, von Neumann audaciously proposed that the Institute for Advanced Study build one itself, on its new campus beyond the Graduate College. He envisioned an “all-purpose, automatic, electronic computing machine” with stored programs: “I propose to store everything that has to be remembered by the machine, in these memory organs,” he wrote, including “the coded, logical instructions which define the problem and control the functioning of the machine.” This describes the modern computer exactly.
Von Neumann’s suggestion of building some kind of mechanical apparatus on the Institute grounds was greeted with dismay by many of the aloof intellectuals there, horrified by the thought of greasy mechanics with soldering guns. Nearby homeowners complained about potential noise and nuisance. But the Electronic Computer Project went ahead anyway, starting in November 1945 with ample funding from the military, plus additional contributions from the University and other sources. Young engineers were lured with a promise of free enrollment as Princeton Ph.D. students.
Called MANIAC, for Mathematical Analyzer, Numerical Integrator, and Computer, it was meant to improve in every way upon ENIAC. The Penn machine had 17,500 vacuum tubes, each prone to fizzling; the Institute’s, only 2,600. ENIAC was 100 feet long and weighed 30 tons; MANIAC was a single 6-foot-high, 8-foot-long unit weighing 1,000 pounds. Most crucially, MANIAC stored programs, something ENIAC’s creators had pondered but not attempted.
Assembly of the computer — from wartime surplus parts — began in the basement of Fuld Hall at the Institute; in early 1947, the project moved to a low, red-brick building nearby, paid for by the Atomic Energy Commission (the building now houses a day-care center). Not for six years would MANIAC be fully operational. The design choices von Neumann and his team made in the first few months reverberate to this day.
For example, they chose to use Turing’s binary system (0s and 1s) instead of a decimal system, and collaborator John Tukey *39, a Princeton professor, coined the term “bit.” So vast was their influence, the internal arrangement of today’s computers is termed the von Neumann architecture.
Von Neumann wanted MANIAC to jump-start a computer revolution, transforming science by solving old, impossible problems at electronic speeds. To maximize its impact upon the world, he eschewed any patent claims and published detailed reports about its progress. “Few technical documents,” Dyson writes, “have had as great an impact, in the long run.”
Seventeen stored-program computers across the planet soon were built following its specifications, including the identically named MANIAC at Los Alamos and the first commercially available IBM machine.
Controlled mysteriously from inside instead of outside, MANIAC seemed to many observers uncannily like an electronic brain. The great breakthrough was the set of 40 cylinders that surrounded its base like a litter of piglets. In an ingenious technical achievement, these cathode-ray tubes (similar to those coming into use for television) provided the world’s first substantial random-access memory.
One could lean over and literally watch the 1,024 bits of memory flickering on a phosphorescent screen on top of each tube, which Dyson calls the genesis of the whole digital universe. Such tubes had been perfected at Manchester University, England, where Turing was a consultant.
“The fundamental conception is owing to Turing,” von Neumann said of MANIAC. A decade earlier, the young Brit had proposed a tape crawling by with numbers on it; now MANIAC flashed at incredible speed the electronic equivalent of zeros and ones in glowing phosphor.
By our standards, MANIAC may seem a modest achievement: As Dyson notes, the computer’s entire storage (five kilobytes) equals less memory than is required by a single icon on your laptop today. No one yet had invented a modern programming language; just to do the equivalent of hitting the backspace key, science writer Ed Regis says, meant precisely coding in something like 1110101.
And the computer broke down frequently — all 40 memory tubes had to be working perfectly at once. “The sensitivity of the memory, that was a big problem,” recalls UCLA professor emeritus Gerald Estrin, who was hired by von Neumann in 1950 to design the input-output device, a paper-tape reader. “If there was a storm with lightning, you would feel it in loss of bits. We spent many nights on the floor trying to tune it up.”