Tetrad

A tetrad is a "group of four". It may refer to:

See also

Tetrad (Greek philosophy)

The tetrad was the name given to the number four in Pythagorean philosophy. There were four seasons and four elements, and the number was also associated with planetary motions and music.

See also

References

Nibble

In computing, a nibble (often nybble or even nyble to match the vowels of byte) is a four-bit aggregation, or half an octet. It is also known as half-byte or tetrade. In a networking or telecommunication context, the nibble is often called a semi-octet,quadbit, or quartet. A nibble has sixteen (2⁴) possible values. A nibble can be represented by a single hexadecimal digit and called a hex digit.

A full byte (octet) is represented by two hexadecimal digits; therefore, it is common to display a byte of information as two nibbles. Sometimes the set of all 256 byte values is represented as a table 16×16, which gives easily readable hexadecimal codes for each value.

Four-bit computer architectures use groups of four bits as their fundamental unit. Such architectures were used in early microprocessors and pocket calculators and continue to be used in some microcontrollers.

History

The term 'nibble' originates from its representing 'half a byte', with 'byte' a homophone of the English word 'bite'.