Master/slave is the historical terminology for a model of asymmetric communication or control where one device or process (the "master") controls one or more other devices or processes (the "slaves") and serves as their communication hub. 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]
The master/slave terminology was first used in 1904.[4] Since the early 21st century, the terms have become a subject of controversy from their association with slavery and some organizations have opted to replace them with alternative terms.[5][6][7]
In electronics, master/slave relationships are used to describe some of the following scenarios:
In parallel ATAhard drive arrangements, the terms master and slave are used to describe drives on the same cable, but neither drive has control or priority over the other.
In AXI, master and slave have differing roles, with master initiating transactions and the slave responding to those transactions.
A Serial Peripheral Interface bus typically has a single master controlling multiple slaves. Many people recommend using more modern terms (main/sub, controller/peripheral, etc.) and discontinuing the use of master/slave terms.[8][9][10][11]
Edge-triggered flip-flops can be created by arranging two latches (master latch and slave latch) in a master/slave configuration. It is named because the master latch controls the slave latch's value and forces the slave latch to hold its value, as the slave latch always copies its new value from the master latch.
In database replication, the master database is regarded as the authoritative source, and the slave (also called replica) databases are synchronized to it.
In photography, secondary or slave flash units may be synchronized to the master unit to provide light from additional directions.
Duplication is often done with several cassette tapes or compact disc recorders linked together. Operating the controls on the master triggers the same commands on the slaves so that recording is done in parallel.
Railway locomotives operating in multiple (for example: to pull loads too heavy for a single locomotive) can be referred to as a master/slave configuration with the operation of all locomotives in the train slaved to the controls of the first locomotive. See Multiple-unit train control.
In automotive engineering, the master cylinder is a control device that converts force into hydraulic pressure in the brake system. This device controls slave cylinders located at the other end of the hydraulic system.
In the creation of audio recordings, a master copy is created as a finalization of the audio mix, to save it to be used as a source for future copies.
A primary standard in metrology have been referred to as a "master" (e.g. master kilogram).
Early usagesEdit
The master/slave terminology was used in 1988 for RFC 1059 and in 1997 for RFC 2136, related to the domain name system. In 2020, Paul Vixie commented on his choice of words:
I introduced the master/slave terminology in RFC 2136, because I needed names for the roles in an AXFR/IXFR transaction, and the zone transfer hierarchy could be more than one layer deep, such that a server might initiate some AXFR/IXFR's to the "primary master" but then respond to AXFR/IXFR's from other servers. In retrospect I should have chosen the terms, "transfer initiator" and "transfer responder". However, the hydraulic brake and clutch systems in my car had "master cylinders" and "slave cylinders", and so I did not think I was either inventing a new use for the words "master" and "slave", or that my use of them for this purpose would be controversial.[12]
In 2003, after receiving a discrimination complaint from a county employee, the County of Los Angeles in California asked that manufacturers, suppliers and contractors stop using master and slave terminology on products.[15][16] Following complaints, the County of Los Angeles issued a statement saying that the decision was "nothing more than a request".[15] Media analytics company Global Language Monitor placed the term first in their annual list of politically charged language for 2004.[17] In 2018, after a heated debate, developers of the Python programming language replaced the term.[7] The Black Lives Matter movement in the United States sparked renewed discussion and terminology changes in 2020.[18] Some have argued that the change is superficial and that companies should make real change to support the black community.[19][6]Google's developer documentation style guide recommends avoiding the term master in software documentation, especially in combination with slave.[20]
Other terminologyEdit
Various replacement terms for 'master' or 'slave' have been proposed and implemented. In 2020, GitHub replaced the default 'master' git branch with 'main'.[18] Other replacement names include 'default', 'primary', 'controller', 'root', 'initiator', 'leader', 'director', 'manager'; and for 'slave': 'performer', 'worker', 'peripheral', 'responder', 'device', 'replica', 'satellite', and 'secondary'.[18][6][21][22][23]Python switched to 'main', 'parent', and 'server'; and 'worker', 'child', and 'helper', depending on context.[7][24] The Linux kernel has adopted a similar policy to use more specific terms in new code or documentation.[22] Other projects and standards have used alternative terms since their inception.
^Eglash, Ron (2007). "Broken Metaphor: The Master–Slave Analogy in Technical Literature". Technology and Culture. 48 (2): 360–369. doi:10.1353/tech.2007.0066. S2CID 1358719.
^Ellis, Leonard (2020-06-18). "It's Time for IEEE to Retire 'Master / Slave'". EE Times. Retrieved 2020-09-26.
^ abc"Tech Confronts Its Use of the Labels 'Master' and 'Slave'". Wired. ISSN 1059-1028. Retrieved 2020-07-14.
^ abc"'Master/Slave' Terminology Was Removed from Python Programming Language". Vice.com. September 13, 2018. Retrieved 2020-07-14.
^Dhaker, Piyu (2018). "Introduction to SPI Interface". Analog Dialogue. from the original on 2023-05-25. Retrieved 2023-07-21.
^'Master/slave' named most politically incorrect term, Seattle PI, December 2, 2004, "We found 'master/slave' to be the most egregious example of political correctness in 2004," said Paul JJ Payack, president of The Global Language Monitor.
^ abcCimpanu, Catalin (14 June 2020). "GitHub to replace "master" with alternative term to avoid slavery references". ZDNet. Retrieved 3 November 2022.
^Shankland, Stephen (2020-06-10). "Tech terms face scrutiny amid anti-racism efforts". CNET. Retrieved 2020-07-06.
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For the master branch in Git version control see Git Conventions For mastering in audio processing see Mastering audio Master slave is the historical terminology for a model of asymmetric communication or control where one device or process the master controls one or more other devices or processes the slaves and serves as their communication hub 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 The master slave terminology was first used in 1904 4 Since the early 21st century the terms have become a subject of controversy from their association with slavery and some organizations have opted to replace them with alternative terms 5 6 7 Contents 1 Examples 2 Early usages 3 Terminology concerns 3 1 Other terminology 4 See also 5 ReferencesExamples EditThis section needs additional citations for verification Please help improve this article by adding citations to reliable sources in this section Unsourced material may be challenged and removed Find sources Master slave technology news newspapers books scholar JSTOR November 2022 Learn how and when to remove this template message In electronics master slave relationships are used to describe some of the following scenarios In parallel ATA hard drive arrangements the terms master and slave are used to describe drives on the same cable but neither drive has control or priority over the other A master clock that provides time signals used to synchronize one or more slave clocks as part of a clock network In AXI master and slave have differing roles with master initiating transactions and the slave responding to those transactions A Serial Peripheral Interface bus typically has a single master controlling multiple slaves Many people recommend using more modern terms main sub controller peripheral etc and discontinuing the use of master slave terms 8 9 10 11 Edge triggered flip flops can be created by arranging two latches master latch and slave latch in a master slave configuration It is named because the master latch controls the slave latch s value and forces the slave latch to hold its value as the slave latch always copies its new value from the master latch In database replication the master database is regarded as the authoritative source and the slave also called replica databases are synchronized to it In photography secondary or slave flash units may be synchronized to the master unit to provide light from additional directions Duplication is often done with several cassette tapes or compact disc recorders linked together Operating the controls on the master triggers the same commands on the slaves so that recording is done in parallel Railway locomotives operating in multiple for example to pull loads too heavy for a single locomotive can be referred to as a master slave configuration with the operation of all locomotives in the train slaved to the controls of the first locomotive See Multiple unit train control In automotive engineering the master cylinder is a control device that converts force into hydraulic pressure in the brake system This device controls slave cylinders located at the other end of the hydraulic system In the creation of audio recordings a master copy is created as a finalization of the audio mix to save it to be used as a source for future copies A primary standard in metrology have been referred to as a master e g master kilogram Early usages EditThe master slave terminology was used in 1988 for RFC 1059 and in 1997 for RFC 2136 related to the domain name system In 2020 Paul Vixie commented on his choice of words I introduced the master slave terminology in RFC 2136 because I needed names for the roles in an AXFR IXFR transaction and the zone transfer hierarchy could be more than one layer deep such that a server might initiate some AXFR IXFR s to the primary master but then respond to AXFR IXFR s from other servers In retrospect I should have chosen the terms transfer initiator and transfer responder However the hydraulic brake and clutch systems in my car had master cylinders and slave cylinders and so I did not think I was either inventing a new use for the words master and slave or that my use of them for this purpose would be controversial 12 Said hydraulic brakes for the automotive industry were patented in 1917 by Malcolm Loughead 13 The term slave cylinder was used in other patent applications including one by Robert Esnault Pelterie published in 1919 14 Terminology concerns EditIn 2003 after receiving a discrimination complaint from a county employee the County of Los Angeles in California asked that manufacturers suppliers and contractors stop using master and slave terminology on products 15 16 Following complaints the County of Los Angeles issued a statement saying that the decision was nothing more than a request 15 Media analytics company Global Language Monitor placed the term first in their annual list of politically charged language for 2004 17 In 2018 after a heated debate developers of the Python programming language replaced the term 7 The Black Lives Matter movement in the United States sparked renewed discussion and terminology changes in 2020 18 Some have argued that the change is superficial and that companies should make real change to support the black community 19 6 Google s developer documentation style guide recommends avoiding the term master in software documentation especially in combination with slave 20 Other terminology Edit Various replacement terms for master or slave have been proposed and implemented In 2020 GitHub replaced the default master git branch with main 18 Other replacement names include default primary controller root initiator leader director manager and for slave performer worker peripheral responder device replica satellite and secondary 18 6 21 22 23 Python switched to main parent and server and worker child and helper depending on context 7 24 The Linux kernel has adopted a similar policy to use more specific terms in new code or documentation 22 Other projects and standards have used alternative terms since their inception See also EditFlexible single master operation Bus mastering Master clock Multi master replication SCSI initiator and targetReferences Edit Master slave terminology alternatives you can use right now TheServerSide com Description of the Microsoft Computer Browser Service from Microsoft KnowledgeBase Microsoft Support support microsoft com Eglash Ron 2007 Broken Metaphor The Master Slave Analogy in Technical Literature Technology and Culture 48 2 360 369 doi 10 1353 tech 2007 0066 S2CID 1358719 Ellis Leonard 2020 06 18 It s Time for IEEE to Retire Master Slave EE Times Retrieved 2020 09 26 a b c Tech Confronts Its Use of the Labels Master and Slave Wired ISSN 1059 1028 Retrieved 2020 07 14 a b c Master Slave Terminology Was Removed from Python Programming Language Vice com September 13 2018 Retrieved 2020 07 14 Dhaker Piyu 2018 Introduction to SPI Interface Analog Dialogue Archived from the original on 2023 05 25 Retrieved 2023 07 21 Open Source Hardware Association A Resolution to Redefine SPI Signal Names Nathan Seidle A redefinition of SPI signal names Utah State University ECE 3700 SPI Chip to Chip Communication Re DNSOP Question regarding RFC 8499 Loughhead Malcolm Braking apparatus U S Patent no 1 249 143 filed 1917 January 22 issued 1917 December 4 Hydraulic power transmission installation a b Master and slave computer labels unacceptable officials say CNN November 26 2003 Master Slave Snopes 9 December 2007 Master slave named most politically incorrect term Seattle PI December 2 2004 We found master slave to be the most egregious example of political correctness in 2004 said Paul JJ Payack president of The Global Language Monitor a b c Cimpanu Catalin 14 June 2020 GitHub to replace master with alternative term to avoid slavery references ZDNet Retrieved 3 November 2022 Shankland Stephen 2020 06 10 Tech terms face scrutiny amid anti racism efforts CNET Retrieved 2020 07 06 Google Developer Style Guide I2C bus specification Rev 7 PDF NXP Semiconductors October 1 2021 Archived from the original PDF on April 26 2021 Retrieved June 4 2022 non primary source needed a b Cimpanu Catalin Linux team approves new terminology bans terms like blacklist and slave ZDNet A Resolution to Redefine SPI Signal Names Open Source Hardware Association 7 January 2022 Issue 34605 Avoid master slave terminology Python tracker bugs python org Retrieved 2020 07 13 Retrieved from https en wikipedia org w index php title Master slave technology amp oldid 1180679621, wikipedia, wiki, book, books, library,
