Endianness

Endianness is the order in which a computer stores or transmits the bytes of a multibyte value. The main conventions are big-endian and little-endian.

Big-endian: A byte order that places the most significant byte of a multibyte value first. It is one of the two principal ways to arrange a value’s bytes.
Network byte order: The big-endian byte order used for multibyte numbers in Internet protocols. It establishes a shared byte order for networked systems.
PDP-11: A family of 16-bit minicomputers introduced by Digital Equipment Corporation in 1970. Its byte-addressable architecture helped popularize little-endian representation.
Middle-endian: A byte-order arrangement in which neither the most nor least significant byte comes first. It is a rare alternative to the usual big-endian and little-endian arrangements.
Little-endian: A byte order that places the least significant byte of a multibyte value first. It reverses big-endian’s byte sequence for multibyte values.
Binary file format: A file format that encodes data as bytes rather than as plain text. Programs must know the format’s byte order to decode multibyte fields correctly.
Motorola 68000: A 16/32-bit microprocessor family introduced by Motorola in 1979. Its big-endian design became influential in workstations and early personal computers.
Bit endianness: The order in which bits are transmitted or numbered within a data unit. It concerns bit order, a separate convention from the byte order meant by endianness.
Byte: A unit of digital information consisting of eight bits in most modern computing systems. Endianness determines the order of these units, not the order of bits within one.
Application binary interface: A set of rules governing how compiled software components interact on a platform. Endianness can affect how an interface represents multibyte values in memory.

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