Cryptonomicon

makes use of these routines to output the contents of a text file in Morse code, by flashing one of those LEDs. And while all kinds of useless crap has been scrolling across the screen of his computer as camouflage, Randy's been hunched over gazing into the subliminal channel of that blinking LED, reading the contents of the decrypted Arethusa intercepts. One of which says:

THE PRIMARY IS CODE NAMED GOLGOTHA. COORDINATES OF THE MAIN DRIFT ARE AS FOLLOWS: LATITUDE NORTH (etc.)

Chapter 91 THE BASEMENT

At this point in history (April of 1945) the word that denotes a person who sits and performs arithmetical calculations is 'computer.' Waterhouse has just found a whole room full of dead computers. Anyone in his right mind-anyone other than Waterhouse and some of his odd Bletchley Park friends, like Turing-would have taken one look at these computers and assumed that they were the accounting department, or something, and that each slave in the room was independently toting up figures. Waterhouse really oughtto remain open to this idea, because it is so obvious. But from the very beginning he has had a hypothesis of his own, much more interesting and peculiar.

It is that the slaves were functioning, collectively, as cogs in a larger computation machine, each performing a small portion of a complex calculation: receiving numbers from one computer, doing some arithmetic, producing new numbers, passing them on to another computer.

Central Bureau is able to trace the identities of five of the dead slaves. They came from places like Saigon, Singapore, Manila, and Java, but they had in common that they were ethnic Chinese and they were shopkeepers. Apparently the Nipponese had cast a wide net for expert abacus users and brought them together, from all over the Co-Prosperity Sphere, to this island in Manila Bay.

Lawrence Waterhouse tracks down a computer of his own in the ruins of Manila, a Mr. Gu, whose small import/export business was destroyed by the war (it is hard to run such a business when you are on an island, and every ship that leaves or approaches the island gets sunk by Americans). Waterhouse shows Mr. Gu photos of the abaci as they were left by the dead computers. Mr. Gu tells him what numbers are encoded in those bead positions, as well as giving Waterhouse a couple of days' tutorial on basic abacus technique. The important thing learned from this is not really abacus skills but rather the remarkable speed and precision with which a computer like Mr. Gu can churn out calculations.

At this point, Waterhouse has reduced the problem to pure data. About half of it's in his memory and the other half scattered around on his desk. The data includes all of the scratch paper left behind by the computers. To match up the numbers on the scratch paper with the numbers left on the abaci, and thus to compile a flash-frozen image of the calculations that were underway in that room when the apocalypse struck, is not that difficult-at least, by the standards of difficulty that apply during wartime, when, for example, landing several thousand men and tons of equipment on a remote island and taking it from heavily armed, suicidal Japanese troops with the loss of only a few dozen lives is considered to be easy.

From this it is possible (though it approaches being difficult) to generalize, and to figure out the underlying mathematical algorithm that generated the numbers on the abaci. Waterhouse becomes familiar with some of the computers' handwriting, and develops evidence that slips of scratch paper were being handed from one computer to another and then to yet another. Some of the computers had logarithm tables at their stations, which is a really important clue as to what they were doing. In this way he is able to draw up a map of the room, with each computer's station identified by number, and a web of arrows interconnecting the stations, depicting the flow of paper, and of data. This helps him visualize the collective calculation as a whole, and to reconstruct what was going on in that subterranean chamber.

For weeks it comes in bits and pieces, and then one evening, some switch turns on in Lawrence Waterhouse's mind, and he knows, in some preconscious way, that he's about to get it. He works for twenty-four hours. By that point he has come up with a lot of evidence to support, and none to contradict, the hypothesis that this calculation is a variant of a zeta function. He naps for six hours, gets up, and works for another thirty. By that point he's figured out that it definitely is some kind of zeta function, and he's managed to figure out several of its constants and terms. He almost has it now. He sleeps for twelve hours, gets up and walks around Manila to clear his head, goes back to work, and hammers away at it for thirty-six hours. This is the fun part, when big slabs of the puzzle, painstakingly assembled from fragments, suddenly begin to lock together, and the whole thing begins to make sense.

It all comes down to an equation written down on one sheet of paper. Just looking at it makes him feel weirdly nostalgic, because it's the same type of equation he used to work with back at Princeton with Alan and Rudy.

Another pause for sleep, then, because he has to be alert to do the final thing.

The final thing is as follows: he goes into the basement of a building in Manila. The building has been turned into a signals intelligence headquarters by the United States Army. He is one of some half-dozen people on the face of the planet who are allowed to enter this particular room. The room amounts to a bit more than a quarter of the basement's total square footage, and in fact shares the basement with several other rooms, some of which are larger than it is, and some of which are serving as offices for men with higher rank than Waterhouse wears on his uniform. But there are a few oddities connected with Waterhouse's room:

(1) At any given moment, no fewer than three United States Marines are loitering directly in front of the door of this room, carrying pump shotguns and other weapons optimized for close-range indoor flesh- shredding.

(2) Lots of power cables go into this room; it has its own fuse-panel, separate from the rest of the building's electrical system.

(3) The room emits muffled, yet deafening quasimusical noises.

(4) The room is referred to as the Basement, even though it's only part of the basement. When 'the Basement' is written down, it is capitalized. When someone (let's say Lieutenant Colonel Earl Comstock) is going to verbalize this, he will come to a complete stop in mid-sentence, so that all of the preceding words kind of pile into each other like cars in a colliding train. He will, in fact, bracket 'the Basement' between a pair of full one-second- long caesuras. During the first of these, he will raise his eyebrows and purse his lips simultaneously, altering the entire aspect ratio of his face so that it becomes strikingly elongated in the vertical dimension, and his eyes will dart sideways in case any Nipponese spies somehow managed to escape the recent apocalypse and found a place to lurk around the fringes of his peripheral vision. Then he will say 'the' and then he will say 'Basement,' drawing out the sand primly articulating the t. And then will come another caesura during which he will incline his head towards the listener and fix him with a sober, appraising look, seeming to demand some kind of verbal or gestural acknowledgment from the listener that something appallingly significant has just passed between them. And then he will continue with whatever he was saying.

Waterhouse nods to the Marines, one of whom hauls the door open for him. A really funny thing happened shortly after the Basement was established, when it was still just a bunch of wooden crates and a stack of 32-foot- long sewer pipe segments, and the electricians were still running in the power lines: Lieutenant Colonel Earl Comstock tried to enter the Basement to inspect it. But owing to a clerical error, Lieutenant Colonel Earl Comstock's name was not on the list, and so a difference of opinion ensued that culminated with one of the Marines drawing his Colt .45 and taking the safety off and chambering a round, pressing the barrel of the weapon directly into the center of Comstock's right thigh, and then reminiscing about some of the spectacular femur-bursting wounds he had personally witnessed on places like Tarawa and in general trying to help Comstock visualize just what his life would be like, both short— and long-term, if a large piece of lead were to pass through the middle of said major bone. To everyone's surprise, Comstock was delighted with this encounter, almost enchanted, and hasn't stopped talking about it since. Of course, now his name's on the list.

The Basement is filled with ETC card machines and with several racks of equipment devoid of corporate logos, inasmuch as they were designed and largely built by Lawrence Pritchard Waterhouse in Brisbane. When all of these things are hooked together in just the right way, they constitute a Digital Computer. Like a pipe organ, a Digital Computer is not so much a machine as a meta-machine that can be made into any of a number of different