Inventing the Internet Again
FOR THE FIRST TIME IN HIS LIFE as an engineer, Paul Baran was "scared stiff." That can happen to people who stumble too close to the abyss of 20th-century history and look over the edge. Born in 1926 in a house in a corner of Poland that had been claimed by three different nations during his parents' tenure, brought to America by his family at the age of 2, Baran was a child of European tempests.
But now, in the heady Southern California of the 1950s, the young Hughes Aircraft engineer found himself working in an American crucible. He was a design engineer for the Minuteman missile control system. Unlike the liquid-fueled Titans of the previous era, which required hours of preparation before they could fly, Minuteman could be instantly rocketed into the sky. To the Pentagon this seemed safer. The solid-fueled rockets would not be vulnerable for hours on the ground awaiting fueling. But Baran and his colleagues knew that this would be the most deadly and dangerous military system ever built. One accident and a cloud of missiles was on its way.
Appreciating the risks in the proposed design, Hughes summoned Warren McCullough from MIT as a consultant on human behavior. An expert on command and control-and a psychiatrist and brain surgeon to boot-McCullough explained the emerging facts of life. Throughout history, he told the Hughes engineers, the real command of the battle migrated to the men closest to the enemy. The man in the crow's nest, not the officers on the ship's bridge, was in de facto control. What he saw and reported determined the captain's orders. Regardless of nominal chains of command, the real governance of history moved to individual people on the front lines, often frightened or panicked at the time. But in the nuclear age, no such single person, necessarily fallible, could ever be trusted. Analyzing the technical problems of creating a command- and-control system for Minuteman, Paul Baran found himself abruptly in the crow's nest, stricken by historic terror-"scared stiff," as he recalls. It was clear to him that the problem was systemic; it could not be solved by tweaking the command-and-control schemes then being proposed at Hughes.
To explore the problem more broadly, Baran in 1959 left Hughes for RAND, the not-for-profit (the name stands for "R&D") set up after World War II to harbor the systems analysis skills developed during the war. At RAND the formidable strategist Albert Wohlstetter was demonstrating that in a matter of minutes Soviet short-range missiles could take out all U.S. foreign strategic air command bases encircling the Soviet Union. Then the Soviets could say stick 'em up-demanding surrender on the basis of the vulnerability of remaining U.S. missiles to superior Soviet forces. In many vivid papers and speeches, Wohlstetter relentlessly presented his argument that U.S. forces faced a "missile gap." The famed Alsop brothers, leading columnists of the day (Stewart was the father of the computer writer), echoed the Wohlstetter claims. John Kennedy listened and made the gap a theme of his 1960 presidential campaign.
Wohlstetter and his colleagues urged that the Pentagon redeploy its strategic forces to the United States and endow them with a second-strike capability-that is, to withstand a first strike and retaliate in kind. Greatly reducing the temptation to go first, this posture would escape the dangerous hair-trigger tenterhooks of the early cold war.
A viable second-strike capability, however, assumed that the command, control, and communications systems would remain intact. It was here that Baran fretted. He saw that one nuclear explosion at high altitude would affect the ionosphere for many hours and thus wipe out all long-range, high-frequency radio communications. In addition, one strike at the centralized switching nodes of AT&T would destroy the rest of the control network. The missile system might endure, but it would be deaf and blind.
Plunging deeper into history than Kennedy had, Baran resolved to design a communications system that could survive a nuclear attack and save the second-strike deterrent. He took inspiration from another idea of MIT's McCullough-a parallel computer system with adaptive redundancy. Like the human brain, such a system could reconfigure itself to work even after portions were destroyed. But using the noise-prone analog circuits of the time, it was impossible to build the necessary switches. Baran concluded that all the traffic would have to be digital. Moreover, the digital traffic would have to be broken into short message blocks now called "packets," each containing its own routing information, like a DNA molecule, and able to replicate itself correctly whenever a transmission error occurred. With many additions and permutations, his original design is today termed the Internet, and it is shaping the emerging history of the 21st century.