History Software Engineering

The Bit – Binary Digit 0 or 1 – 1948 AD

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The Bit

Claude E. Shannon (1916–2001), John W. Tukey (1915–2000)

“It was the German mathematician Gottfried Wilhelm Leibniz (1646–1716) who first established the rules for performing arithmetic with binary numbers. Nearly 250 years later, Claude E. Shannon realized that a binary digit—a 0 or a 1—was the fundamental, indivisible unit of information.

Shannon earned his PhD from MIT in 1940 and then took a position at the Institute for Advanced Study in Princeton, New Jersey, where he met and collaborated with the institute’s leading mathematicians working at the intersection of computing, cryptography, and nuclear weapons, including John von Neumann, Albert Einstein, Kurt Gödel, and, for two months, Alan Turing.

In 1948, Shannon published “A Mathematical Theory of Communication” in the Bell System Technical Journal. The article was inspired in part by classified work that Shannon had done on cryptography during the war. In it, he created a mathematical definition of a generalized communications system, consisting of a message to be sent, a transmitter to convert the message into a signal, a channel through which the signal is sent, a receiver, and a destination, such as a person or a machine “for whom the message is intended.”

Shannon’s paper introduced the word bit, a binary digit, as the basic unit of information. While Shannon attributed the word to American statistician John W. Tukey, and the word had been used previously by other computing pioneers, Shannon provided a mathematical definition of a bit: rather than just a 1 or a 0, it is information that allows the receiver to limit possible decisions in the face of uncertainty. One of the implications of Shannon’s work is that every communications channel has a theoretical upper bound—a maximum number of bits that it can carry per second. As such, Shannon’s theory has been used to analyze practically every communications system ever developed—from handheld radios to satellite communications—as well as data-compression systems and even the stock market.

Shannon’s work illuminates a relationship between information and entropy, thus establishing a connection between computation and physics. Indeed, noted physicist Stephen Hawking framed much of his analysis of black holes in terms of the ability to destroy information and the problems created as a result.”

SEE ALSO Vernam Cipher (1917), Error-Correcting Codes (1950)

Mathematician and computer scientist Claude E. Shannon.

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History Software Engineering

The Jacquard Loom – 1801 AD

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The Jacquard Loom

Joseph-Marie Jacquard (1752–1834)

“In 1801, French weaver Joseph-Marie Jacquard invented a way to accelerate and simplify the time-consuming, complex task of weaving fabric. His technique was the conceptual precursor to binary logic and programming that exists today.

While looms of the 18th century could create complex patterns, doing so was an entirely manual affair, requiring an extraordinary amount of time, constant vigilance to avoid mistakes, and skilled hands—especially with intricate fabric patterns such as damask and brocade. Jacquard realized that despite the complexity of a pattern, the act of weaving was a repetitive process that could be carried out mechanically. His invention used a series of cards laced together in a continuous chain, with a row on each card where holes could be punched, corresponding with one row of the fabric pattern. Some cards had holes in the specified position, while others did not. Essentially, the punched cards were a control mechanism that contained data—like binary 0s and 1s—that directed a sequence of actions, in this case how a loom could be mechanized to weave a repeating pattern. A hole would cause a corresponding thread to be raised, while no hole would cause the thread to be lowered. The actual mechanism involved a rod that would either travel through the hole or be stopped by the card; each rod was linked to a hook, and together they formed the harness that controlled the position of the threads. After the threads were raised or lowered, the shuttle holding another roll of thread would zip from one side of the loom to the other, completing the weave. Then the rods in the holes would retract, the card would advance, and the process would start over again.

Jacquard’s invention evolved from earlier ideas by Jacques de Vaucanson (1709–1782), Jean-Baptiste Falcon, and Basile Bouchon, the last of whom invented a way to control a loom using perforated tape in 1725. Later inventors would take that concept and use punched cards to represent numerical data and other types of information.”

SEE ALSO: Tabulating the US Census (1890)

A jacquard loom in the National Museum of Scotland, Edinburgh. Pins either are stopped by the card or poke through the holes, determining the pattern woven by the loom.”

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