<P> Little - endian format reverses this order: the sequence addresses / sends / stores the least significant byte first (lowest address) and the most significant byte last (highest address). Most computer systems prefer a single format for all its data; using the system's native format is automatic . But when reading memory or receiving transmitted data from a different computer system, it is often required to process and translate data between the preferred native endianness format to the opposite format . </P> <P> The order of bits within a byte or word can also have endianness (as discussed later); however, a byte is typically handled as a single numerical value or character symbol and so bit sequence order is obviated . </P> <P> Both big and little forms of endianness are widely used in digital electronics . The choice of endianness for a new design is often arbitrary, but later technology revisions and updates perpetuate the existing endianness and many other design attributes to maintain backward compatibility . As examples, the IBM z / Architecture mainframes and the Motorola 68000 series use big - endian while the Intel x86 processors use little - endian . The designers of System / 360, the ancestor of z / Architecture, chose its endianness in the 1960s; the designers of the Motorola 68000 and the Intel 8086, the first members of the 68000 and x86 families, chose their endianness in the 1970s . </P> <P> Big - endian is the most common format in data networking; fields in the protocols of the Internet protocol suite, such as IPv4, IPv6, TCP, and UDP, are transmitted in big - endian order . For this reason, big - endian byte order is also referred to as network byte order . Little - endian storage is popular for microprocessors, in part due to significant influence on microprocessor designs by Intel Corporation . Mixed forms also exist, for instance the ordering of bytes in a 16 - bit word may differ from the ordering of 16 - bit words within a 32 - bit word . Such cases are sometimes referred to as mixed - endian or middle - endian . There are also some bi-endian processors that operate in either little - endian or big - endian mode . </P>

What is big endian and little endian architecture