Cryptonomicon

He figured out that mathematicians, unlike carpenters, only needed to have one tool in their toolbox, if it were the right sort of tool. Turing realized that it should be possible to build a meta-machine that could be reconfigured in such a way that it would do any task you could conceivably do with information. It would be a protean device that could turn into any tool you could ever need. Like a pipe organ changing into a different instrument every time you hit a preset button.

The details were a bit hazy. This was not a blueprint for an actual machine, rather a thought experiment that Turing had dreamed up in order to resolve an abstract riddle from the completely impractical world of pure logic. Waterhouse knows this perfectly well. But he cannot get one thing out of his mind as he sits there atop the blast walls at the dark intersection in Bletchley Park: the Turing machine, if one really existed, would rely upon having a tape. The tape would pass through the machine. It would carry the information that the machine needed to do its work.

Waterhouse sits there staring off into the darkness and reconstructs Turing's machine in his mind. More of the details are coming back to him. The tape, he now recollects, would not move through the Turing machine in one direction; it would change direction frequently. And the Turing machine would not just read the tape; it would be able to erase marks or make new ones.

Clearly you cannot erase holes in a paper tape. And just as clearly the tape only moves through this Bletchley Park machine in one direction. So, much as Waterhouse hates to admit this fact to himself, the rack of tubes he just spied is not a Turing machine. It is some lesser device--a special-purpose tool like a punched-card reader or Atanasoffs differential equation solver.

It is still bigger and more fiendishly terrific than anything Waterhouse has ever seen.

A night train from Birmingham blows through, carrying bullets to the sea. As its sound dies away to the south, a motorcycle approaches the park's main gate. Its engine idles as the rider's papers are checked, then Waterhouse hears a Bronx cheer as it surges forward and cuts the sharp turn into the lane. Waterhouse climbs to his feet at the intersection of the walls, and watches carefully as the bike sputters past him and homes in on a "hut" a couple of blocks away. Light suddenly leaks from an open door as the cargo changes hands. Then the light is snuffed and the bike stretches a long loud raspberry down the road to the park's exit.

Waterhouse lets himself down to earth and gropes his way down the road through the moonless night. He stops before the entrance to the hut and listens to it teem for a minute. Then, working up his courage, he steps forward and pushes the wooden door open.

It is unpleasantly hot in here, and the atmosphere is a nauseating distillation of human and machine odors, held in and concentrated by the coffin doors slabbed down over all the windows. Many people are in here, mostly women working at gargantuan electrically powered typewriters. He can see even through his squint that the place is a running sluice for scraps of paper, maybe four by six inches each, evidently brought in by the motorcyclists. Near the door, they have been sorted and stacked up in wire baskets. Thence they go to the women at their giant typewriters.

One of the few men in the place has risen to his feet and is homing in on Waterhouse. He is about Waterhouse's age, that is, in his early twenties. He is wearing a British Army uniform. He has the air of a host at a wedding reception who wants to make sure that even the most long lost, far-flung members of the family are properly greeted. Obviously he is no more a real military man than is Waterhouse himself. No wonder this place is surrounded by so much barbed wire and RAF men with machine guns.

"Good evening, sir. Can I help you?"

"Evening. Lawrence Waterhouse."

"Harry Packard. Pleased to meet you." But he has no idea who Waterhouse is; he is privy to Ultra, but not to Ultra Mega.

"Pleasure's mine. I imagine you'll want to have a look at this." Waterhouse hands him the magic pass. Packard's pale eyes travel over it carefully, then jump around to focus on a few sites of particular interest: the signature at the bottom, the smeared stamp. The war has turned Harry Packard into a machine for scanning and processing slips of paper and he goes about his work calmly and without fuss in this case. He excuses himself, works the crank on a telephone, and speaks to someone; his posture and facial expression suggest it is someone important. Waterhouse cannot hear the words above the clicking and thrumming of the massed typewriters, but he sees interest and bemusement on Packard's young, open, pink face. Packard gives Waterhouse a sidelong glance or two while he is listening to the person at the other end of the line. Then he says something respectful and reassuring into the phone and rings off.