In computer hardware, a word mark or flag is a bit in each memory location on some early variable word length computers (e.g., IBM 1401, 1410, 1620) used to mark the end of a word.[1] 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).[2]
The term word mark should not be confused with group mark or with record mark, which are distinct characters.
References
edit- ^ IBM (April 1962). IBM 1401 Data Processing System: Reference Manual (PDF). p. 20. A24-1403-5. Retrieved 2019-09-30.
- ^ "IBM Archives: 1620 Data Processing System". 23 January 2003. Archived from the original on January 14, 2005.