Master/slave (technology)

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Master/slave is a model of dualistic communication where one device or process has unidirectional control over one or more other devices. In some systems a master is selected from a group of eligible devices, with the other devices acting in the role of slaves.[1][2][3]

In the context of motor control, the master/slave configuration is used for load sharing purposes when two identical motors connected to two different drives are coupled to a common load.[citation needed] One drive is defined as the master and is configured for running in the speed-control mode whereas the other defined as slave is configured for running in torque-control mode.

Examples[edit]

Terminology concerns[edit]

The terminology has often been replaced with something different because the terms "master" and "slave" refer to the practice of slavery.

"Main" & "Secondary" has been proposed, enabling reusable interpretation of the remaining acronym labels for connecting.

One alternative for databases is "primary" and "replica", which is used in the documentation from IBM,[5] Microsoft,[6] Engine Yard,[7] Amazon Web Services/Amazon Relational Database Service,[8] and ACM[9] as well as in Python,[10] Django,[11][12] Drupal,[13] CouchDB,[14] Redis[15] and MediaWiki (which still uses "master").[16][17]

The configuration management tool Salt uses the terms "master" and "minion".[18]

In December 2017, the Internet Systems Consortium decided to allow the words "primary" and "secondary" as a substitute for master/slave terminology in their DNS server software BIND.[19]

In 2003, the County of Los Angeles in California asked that manufacturers, suppliers and contractors stop using "master" and "slave" terminology on products; the county made this request "based on the cultural diversity and sensitivity of Los Angeles County".[20][21] Following outcries about the request, the County of Los Angeles issued a statement saying that the decision was "nothing more than a request".[20] Following the controversy, Global Language Monitor found the term "master/slave" to be the most egregious example of political correctness in 2004, and named it the most politically incorrect term of that year.[22]

See also[edit]

References[edit]

  1. ^ "What is master/slave? - Definition from WhatIs.com".
  2. ^ Description of the Microsoft Computer Browser Service from Microsoft KnowledgeBase
  3. ^ Information on Browser Operation from Microsoft KnowledgeBase
  4. ^ Yu, H. (2002). "Rmpi: Parallel Statistical Computing in R". R News.
  5. ^ "IBM Knowledge Center". www.ibm.com. Retrieved 2018-05-08.
  6. ^ "Configure Database Replicas for Management Points". technet.microsoft.com. Retrieved 2018-05-08.
  7. ^ "Set Up Database Replication". Engine Yard Developer Center. Retrieved 2018-05-08.
  8. ^ "Working with Read Replicas of MariaDB, MySQL, and PostgreSQL DB Instances - Amazon Relational Database Service". docs.aws.amazon.com. Retrieved 2018-05-08.
  9. ^ Savinov, Sergey; Daudjee, Khuzaima (2010-10-30). Dynamic database replica provisioning through virtualization. ACM. pp. 41–46. doi:10.1145/1871929.1871937. ISBN 9781450303804.
  10. ^ "Python joins movement to dump 'offensive' master, slave terms". Retrieved 2018-09-12.
  11. ^ "Fixes #22667. Replaced leader/follower terminology with primary/replica by fcurella · Pull Request #2694 · django/django".
  12. ^ "Multiple databases". Django Project. Retrieved 2018-05-08.
  13. ^ "Replace "master/slave" terminology with "primary/replica"". Drupal.org. 2014-05-28. Retrieved 2018-04-17.
  14. ^ "CouchDB - Replace "master" and "slave" terminology".
  15. ^ "Redis - Replace "master" and "slave" terms in Redis".
  16. ^ "Rename DB_SLAVE constant to DB_REPLICA · wikimedia/mediawiki@950cf60".
  17. ^ https://lists.wikimedia.org/pipermail/wikitech-l/2016-September/086450.html
  18. ^ "Configuring the Salt Minion". SaltStack Inc. Retrieved 2019-04-19.
  19. ^ "ISC explanation via Twitter".
  20. ^ a b "'Master' and 'slave' computer labels unacceptable, officials say". CNN. November 26, 2003.
  21. ^ Master/Slave, Snopes
  22. ^ 'Master/slave' named most politically incorrect term, Seattle PI, December 2, 2004, The computer term "master/slave," which was banned as racially offensive by a Los Angeles County purchasing department, was named the most politically incorrect term of the year.[...] Among other terms on the top 10 list of politically charged words and phrases, issued by the word usage group Global Language Monitor, were "non-same sex marriage" to describe heterosexual unions, "waitron" for waiter or waitress and "higher being" for God, a term some people found too religious.