Master/slave (technology)

Master/slave is 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. Historically, the master/slave terminology has existed for decades, although in the 21st century it has been a subject of controversy due to its association with slavery, and some organizations and products have since replaced it with alternative terms.
Terminology concerns.
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". Following outcries about the request, the County of Los Angeles issued a statement saying that the decision was "nothing more than a request". Following the controversy, Global Language Monitor found the term "master/slave" to be the most egregious example of political incorrectness in 2004, and named it the most politically incorrect term of that year. In 2018, Python replaced the term, after a heated debate. Many developers in the discussion on whether to make the replacement agreed that the term "slave" should be replaced while "master" was not offensive, while others argued that changing "slave" was also unnecessary. There was similarly contentious debate among developers when Django and Drupal (in 2014) and Redis (in 2017) replaced the term. The Black Lives Matter movement sparked that discussion again in 2020. Some have argued that the change is superficial and that companies should make real change to support the black community. See also similar concerns regarding the technology term "Blacklist".
In 2020, the Open Compute Project published "Terminology Guidelines for Inclusion and Openness" which recommends general terminology and commonly used pinout and signal names which to deprecate and suggested replacement terminology. 
Replacements.
Different phrases have been adopted to replace existing usage of the phrase. Some examples include: