# Bit

**See:** Boolean, Boolean Digit, Byte, Bitmap, Kilobit, Quantum Bit, Unit of Information, Truth Value, Bit-Length, Information Theory.

## References

### 2014

- (Wikipedia, 2014) ⇒ http://en.wikipedia.org/wiki/bit Retrieved:2014-10-9.
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**bit**is the basic unit of information in computing and digital communications. A bit can have only one of two values, and may therefore be physically implemented with a two-state device. These values are most commonly represented as . The term*bit*is a portmanteau of binary digit.The two values can also be interpreted as logical values (true/false, yes/no), algebraic signs (+/−), activation states (on/off), or any other two-valued attribute. The correspondence between these values and the physical states of the underlying storage or device is a matter of convention, and different assignments may be used even within the same device or program. The length of a binary number may be referred to as its bit-length.

In information theory, one bit is typically defined as the uncertainty of a binary random variable that is 0 or 1 with equal probability,

^{[1]}or the information that is gained when the value of such a variable becomes known.^{[2]}In quantum computing, a

*quantum bit*or qubit is a quantum system that can exist in superposition of two bit values,*true*and*false*.The symbol for bit, as a unit of information, is either simply

*bit*(recommended by the ISO/IEC standard 80000-13 (2008)) or lowercase*b*(recommended by the IEEE 1541 Standard (2002)). A group of eight bits is commonly called one byte, but historically the size of the byte is not strictly defined.

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