In computer hardware, a word mark or flag is a bit in each memory location on some early
variable word length computer
In computing, a word is any processor design's natural unit of data. A word is a fixed-sized datum handled as a unit by the instruction set or the hardware of the processor. The number of bits or digits in a word (the ''word size'', ''word wid ...
s (e.g.,
IBM 1401
The IBM 1401 is a variable word length computer, variable-wordlength decimal computer that was announced by IBM on October 5, 1959. The first member of the highly successful IBM 1400 series, it was aimed at replacing unit record equipment for pr ...
,
1410,
1620
Events
January–March
* January 7 – Ben Jonson's play ''News from the New World Discovered in the Moon'' is given its first performance, a presentation to King James I of England. In addition to dialogue about actual observ ...
) used to mark the end of a
word
A word is a basic element of language that carries semantics, meaning, can be used on its own, and is uninterruptible. Despite the fact that language speakers often have an intuitive grasp of what a word is, there is no consensus among linguist ...
. Sometimes the actual bit used as a word mark on a given machine is not called ''word mark'', but has a different name (e.g., ''flag'' on the IBM 1620, because on this machine it is multipurpose).
The term ''word mark'' should not be confused with
group mark or with
record mark, which are distinct characters.
References
{{Reflist, 30em
Computing terminology
Early computers