More on this book
Community
Kindle Notes & Highlights
Edgar Allan Poe wrote sixty-five stories. This one, “The Gold-Bug,” is the only one to end with a lecture on cryptanalysis.
Claude Sr. and Mabel were bright threads in Gaylord’s fabric.
He’d been—like Claude Shannon, his greatest student—a basement tinkerer from his earliest memories. Much of his adult life was spent, it turned out, building dogged, untiring mathematical brains of wood and metal, brains that in some ways far outclassed his own—and that would ultimately be the scene of Shannon’s first breakthrough.
Each of those factors formed a variable in—again—a differential equation. A naval battle at that range was not simply a gunfight, but a mathematical race (in which the reward for second place was often a watery grave). In
Thomson’s harmonic analyzer, Ford’s integrator, Bush’s Profile Tracer: conceived in isolation from one another, single-purpose machines built to answer only one specialized question apiece, they still had a crucial quality in common. They were all working models of the physical world—of the slope of a hill or the fall of a shell—simplified down to the essence. They were all, in a way, bare-bones miniatures of the processes they described; they were, in other words, resolutely analog.
Given the pipe wrench, produce the words for that wrench and no other; given the words, produce the wrench. That, Bush taught his students, was the beginning of engineering.
One problem, which measured the effects of the earth’s magnetic field on cosmic rays, took thirty weeks of spinning gears—but when it was done, the differential analyzer had solved, by brute force, equations so complex that even trying to attack them with human brainpower would have been pointless.
the greater the variable, the faster the shaft spun. These, in turn, drove integrators like Ford’s:
said Bush. “When one has a problem before him, say the problem of how a bridge that has not been built will sway in a gusty wind, he proceeds to make a combination of mechanical or electrical elements which will act in exactly the same manner as the bridge—that is, will obey the same differential equations.” For the physicist or engineer, two systems that obey the same equations have a kind of identity—or at least an analogy. And that, after all, is all our word analog means. A digital watch is nothing like the sun; an analog watch is the memory of a shadow’s circuit around a dial.
In response, Bush dreamed of an analyzer that could essentially reassemble itself on the fly: one
took on new urgency with the American entry into the war. The project, also known as the SIGSALY system, consisted of “some forty racks of vacuum tube–powered electrical equipment weighing about fifty-five tons, taking up 2,500 square feet and requiring 30,000 watts of power.” According to one estimate, the system had a $5,000,000 budget in 1943, and it employed a platoon of thirty workers.
Well, the good of this command is that if you’re in a loop you can have this command in that loop and every time it goes around the loop it will put a pulse in and you will hear a frequency equal to how long it takes to go around that loop. And then you can put another one in some bigger loop and so on. And so you’ll hear all of this coming on and you’ll hear this “boo boo boo boo boo boo,” and his concept was that you would soon learn to listen to that and know whether when it got hung up in a loop or something else or what it was doing all this time, which he’d never been able to tell
...more
Whenever we communicate, rules everywhere restrict our freedom to choose the next letter and the next pineapple.I Because these rules render certain patterns more likely and certain patterns almost impossible, languages like English come well short of complete uncertainty and maximal information: the sequence “th” has already occurred 6,431 times in this book, the sequence “tk” just this once.
to communicate is to make oneself predictable.
codebreaking works because our messages are less, much less, than fully uncertain.
Shannon proposed an unsettling inversion. Ignore the physical channel and accept its limits: we can overcome noise by manipulating our messages. The answer to noise is not in how loudly we speak, but in how we say what we say.
“Up until that time, everyone thought that communication was involved in trying to find ways of communicating written language, spoken language, pictures, video, and all of these different things—that all of these would require different ways of communicating,” said Shannon’s colleague Robert Gallager. “Claude said no, you can turn all of them into binary digits. And then you can find ways of communicating the binary digits.” You can code any message as a stream of bits, without having to know where it will go; you can transmit any stream of bits, efficiently and reliably, without having to
...more
The publication of The Mathematical Theory of Communication stands as one of the defining moments in the history of information theory,
telephone company, that inspired the guts of the contraption. Seventy-five electromechanical relays, the sort used as switches in the phone system to connect one call to another, toggled like railroad tracks shifting trains to allow
The relays stored the directions of the right path in “memory”: once the mouse had successfully navigated the maze by trial and error, it could find the cheese a second time with ease.
but rather a “constructive dissatisfaction,” or “a slight irritation when things don’t look quite right.” It was,
Call it ingenious incrementalism—or, as Shannon put it, “It seems to be much easier to make two small jumps than the one big jump in any kind of mental thinking.”
“Shannon’s favorite thing to do was to listen to what you had to say and then just say, ‘What about . . .’ and then follow with an approach you hadn’t thought of. That’s how he gave his advice.” This was how Shannon preferred to teach: as a fellow traveler and problem solver, just as eager as his students to find a new route or a fresh approach to a standing puzzle.
But at a certain point, with all these pieces stripped out, we both saw how to solve it. And then we gradually put all these little assumptions back in and then, suddenly, we saw the solution to the whole problem. And that was just the way he worked. He would find the simplest example of something and then he would somehow sort out why that worked and why that was the right way of looking at it.
Even more conventional professors and old Bell Labs hands would make the trek to Winchester, and Shannon would walk them from room to room, all the while showing off his collection of contraptions
started telling him about it, and for a brief time he got quite enthused about this. And then he said, ‘Nuh-uh, I don’t want to think. I don’t want to think that much anymore.’ It was the beginning of the end in his case, I think. He just—he turned himself off.”
If there can be said to have been an old boys’ club of Silicon Valley in its initial days, then Claude Shannon was a card-carrying member—and he benefited from all the privileges therein.
Shannon answered, “Far beyond any reasonable expectations.” By his own admission, Shannon had been fortunate in his timing, and privileged in knowing certain company founders and securing early investments. The bulk of his wealth was concentrated in Teledyne, Motorola, and HP stock; after getting in on the ground floor, the smartest thing Shannon did was hold on. His
Shannon was an engineer—a man more attuned to practicality than most—and yet he was drawn to the idea that knowledge was valuable for its own sake and that discovery was pleasurable in its own right. As he himself put it, “I’ve been more interested in whether a problem is exciting than what it will do.”
