Byte of the 8080 and the 8086, used in early personal computers, could also perform a small number of operations on the four-bit pairs in a byte, such as the decimal-add-adjust (DAA) instruction. A four-bit quantity is often called a nibble, also "nybble", which is conveniently represented by a single hexadecimal digit. The term "octet" is used to unambiguously specify a size of eight bits. It is used extensively in protocol definitions. Historically, the term "octad" or "octade" was used to denote eight bits as well at least in Western Europe; however, this usage is no longer common. The exact origin
Byte order mark as a byte sequence in various encodings and how those sequences might appear in a text editor that is interpreting each byte as a legacy encoding (CP1252 and caret notation for the C0 controls): Byte order mark The byte order mark (BOM) is a Unicode character, , whose appearance as a magic number at the start of a text stream can signal several things to a program reading the text: BOM use is optional. Its presence interferes with the use of UTF-8 by software that does not expect non-ASCII bytes at the start of a file but that could otherwise