What If the Transistor Was Invented in 1921?

By 1951, six years after the war ended, solid-state valves had replaced vacuum tubes in nearly every device that didn't require enormous power — radios first, then calculating machines, then, improbably fast, something engineers at three competing firms had each started calling, independently, a personal calculating unit: a cabinet the size of a large desk, battery-tolerant, that a single engineer or accountant could operate without a dedicated technician.

It was not yet a computer in any sense a later century would recognize. It could not store a program; every calculation had to be wired or dialed in by hand. But it was small enough, cheap enough, and reliable enough that by 1955 a mid-sized company could afford one, and by 1960 an ambitious research lab had connected four of them together, sharing results over a telephone line, mostly as a way to avoid retyping the same equations into two machines at once.

No one called this a network yet. The engineers who built it were solving a tedious afternoon's problem, not founding an age. Eleanor Voss, consulting for the lab that year at sixty-two, looked at the four linked machines and said, to an assistant who later wrote it down only because it seemed like the kind of thing worth remembering: "This is going to get much bigger than anyone in this room wants to admit."