Bit - peregrineshahin/ChessProgrammingWiki GitHub Wiki

title: Bit

PDP-6 flip-flop stores one bit [1] Bit,

the basic unit of information in information theory and computing - a binary digit, either 0 or 1 in the arithmetical sense, 'false' or 'true' in the boolean sense, black (dark) or white (light) as a Color in Chess, etc..

Quote

by Claude Shannon in A Mathematical Theory of Communication 1948 [2]:

The choice of a logarithmic base corresponds to the choice of a unit for measuring information. If the base 2 is used the resulting units may be called binary digits, or more briefly bits, a word suggested by [J. W. Tukey](https://en.wikipedia.org/wiki/John_Tukey). A device with two stable positions, such as a [relay](https://en.wikipedia.org/wiki/Relay) or a [flip-flops](Memory#FlipFlop "Memory") circuit, can store one bit of information.

Aggregations

Aggregations of bits are used to code numbers, integers or floating point values, characters, codes and sets. Four bits are called a Nibble with 16 states - written as one hexadecimal digit {'0'..'9', 'A'-'F'}. A group of eight Bits, two Nibbles or one Byte with 256 states (e.g. unsigned numbers 0..255) is most often the smallest addressable unit in computer architectures. Bitboards are set-wise bit aggregations which covers all 64 squares of a Chessboard.

Bitwise Arithmetic

Bitwise addition (Modulo 2) and subtraction with aggregations of Bits without overflows can be applied by bitwise exclusive or:

| a | b | a xor b | | --- | --- | --- | | 0 | 0 | 0 | | 0 | 1 | 1 | | 1 | 0 | 1 | | 1 | 1 | 0 |

Least Significant One Bit Most Significant One Bit External Links

References

↑ Bits by Lawrence J. Krakauer
↑ Claude Shannon (1948). A Mathematical Theory of Communication, pdf reprint

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