Octet

An octet is a group consisting of eight (8) elements, but it has several more specific meanings (usually given by a specific field or application):

=Music=

In music, an octet is a musical ensemble consisting of eight instruments or a musical composition written for it.

The two best known octets in European classical music are probably those by Felix Mendelssohn (which is for a double string quartet) and Franz Schubert (which is for clarinet, bassoon, French horn, violin, viola, cello and double bass). Igor Stravinsky also wrote an octet for wind instruments (an unusual grouping of flute, clarinet, two bassoons, two trumpets and two trombones) and Paul Hindemith wrote a lesser known piece for clarinet, bassoon, French horn, violin, two violas, cello and double bass.

Saxophonist David Murray (jazz musician) leads a famous experimental jazz octet, the David Murray Octet.

See also : Octet (Reich)   by Steve Reich

=Computers and networking=

In computer technology and computer network, an octet is a group of 8 Bits. It can be expressed as a decimal integer in the range 0–255, or as a pair of hexadecimal digits such as 5E (=94). In computer technology, an octet is abbreviated o ; for example, Mio for mebioctet and Mo for megaoctet.

On most computers the smallest unit of memory addressing —or byte— is 8 bits, so the terms byte and octet are often used interchangeably. However, the size of a byte is determined by the architecture of a particular computer system: some old computers had 9, 10, or 12-bit bytes, while others had bytes as small as 5 or 6 bits. An octet is always exactly 8 bits. As a result, computer networking standards almost exclusively use octet to refer to the 8-bit quantity.

In some cases a group of 3 bits is also called an octet, as it has 8 possible values. Though one should only use octet with the meaning of 8 bits, the term is often used this way e.g. for the three permission bits (read,write,execute) on Unix-like filesystems.

In French, the word octet is widely used instead of byte

=Chemistry=

In chemistry, an atom in a chemical bond often obeys the octet rule based on the stability of 8 electron in the Valence_shell. Carbon, nitrogen, oxygen, and fluorine always obey the octet rule.