The TCP/IP Guide  9  Networking Fundamentals       9  Backgrounder: Data Representation and the Mathematics of Computing

Backgrounder: Data Representation and the Mathematics of Computing 1 2 3 Decimal, Binary, Octal and Hexadecimal Numbers

Byte versus Octet

There has been some disagreement, and even controversy, surrounding the use of the words byte and octet. The former term has traditionally been the most popular in common parlance for a set of eight bits, especially in North America. However, it is technically not the correct term.

A byte is, formally, the smallest unit of data that can be read from or written to at one time in a computer system. In almost all cases today, that is indeed eight bits, but there are have been some systems where a byte was not eight bits. Some older 36-bit computers used 9-bit bytes, and there were also systems that had byte sizes of 6 or 7 bits, or even variable-sized bytes. For this reason, many people, especially techie professionals, prefer the term octet, which clearly and unambiguously implies “eight”. This term is much more common outside North America.

This matter of octets and bytes is another of the little “tempests in tea pots” that computer people seem to love so much. The bottom line in modern computer systems, however, is that an octet is a byte and a byte in an octet, and the terms can be used interchangeably without too much danger. You will more often see octets used in technical standards. In this Guide, I use the term bytes for a simple reason: it is the term that most people are familiar with, including myself (though bear in mind that I live in North America; if I were European I might have rather different views on this!)

Backgrounder: Data Representation and the Mathematics of Computing 1 2 3 Decimal, Binary, Octal and Hexadecimal Numbers