Slave Master


Master/Slave is a model of communication in which one device (the master) has authority to control other devices (slaves) in the system. The master coordinates and manages data, requests, and processes tasks, while the slaves respond to the master’s commands. This term is considered outdated and inappropriate, with recommended alternative terms being primary/secondary, main/worker, or leader/follower.

Key Takeaways

  1. Master/Slave is a communication model in which one device (master) controls and coordinates the activities of other devices (slaves) in a system.
  2. This terminology has been widely used in various technologies, such as databases, computer networking, and electronics, to depict the relationship between controlling and dependent components.
  3. Due to the historical connotations of the term, many organizations and individuals in the tech industry are advocating for and adopting more inclusive alternative terms like “primary/replica” or “leader/follower” to describe these relationships.


The technology term “Master/Slave” is important because it historically describes a significant communication model in computer systems and networks.

This model is characterized by one central device (the master) controlling or initiating communication with peripheral devices or components (the slaves), ensuring orderly data management and processing.

Master/Slave functionalities can be found in hardware like hard-drives, databases, and distributed computing and network applications.

However, the terminology has become controversial due to its association with racial and social inequality, leading to alternative terms such as “Primary/Secondary” or “Leader/Follower” gaining traction in recent years.

Despite its contentious nature, understanding the Master/Slave concept remains crucial for grasping the fundamentals of various technology architectures and communication protocols.


Master/Slave is a communication model employed in the field of technology, primarily in computer systems, databases, and networking environments, where one device or process takes the dominant role (Master) and the other devices or processes follow the Master’s instructions (Slaves). The key purpose of this architecture is to ensure efficient sharing and utilization of resources, improve performance, and enable a seamless distribution of workloads. Masters are typically responsible for directing and delegating tasks to Slaves, which in turn execute the orders promptly, resulting in better management of concurrent processes.

In many cases, the Master is also expected to monitor the Slaves and ensure that the results are communicated back to the primary device or process effectively. This communication model is particularly helpful in large scale computing and networking environments where numerous devices are involved.

One common application of Master/Slave architecture is in RAID (Redundant Array of Independent Disks) configurations, where the Master disk stores data and optimizes accessibility and speed, while the Slave disks maintain redundancy, ensuring data integrity and backup. Another widespread application of this concept is in the field of distributed computing, where a central server or a Master computer manages the overall processing burden by allocating specific tasks to subordinate Slave computers.

This method effectively improves processing times and ensures optimal resource utilization while allowing for simplified maintenance and error management.

Examples of Master/Slave

The master/slave terminology is used in various technological contexts to describe the relationship between a controlling component (the master) and a dependent component (the slave). Here are three real-world examples:

Computer Hard Drives: In older computer systems, the primary (master) and secondary (slave) hard drives were connected to a single cable connected to the motherboard. The master drive typically contained the operating system and system files, while the secondary drive was used to store additional data. The primary drive controlled access to the secondary drive, hence the master/slave terminology.

Databases: In database management systems, a master/slave configuration is sometimes used for replication purposes. The master database is the primary source of data and controls the flow of updates, while the slave database is a replica that queries and reads data. This setup is used to maintain a backup copy of data, improve read performance by offloading queries, and distribute data across multiple locations.

Robotics and Automation: In the context of robotics and automation, the master/slave configuration is often used for control systems. A master device, such as a computer or a control unit, sends commands to one or more slave devices, which are typically actuator motors or sensors. The slave devices follow the instructions sent by the master device, enabling coordinated movement and accurate control over the automated systems. This concept is also widely used in industrial control systems and machine-to-machine communication.

Master/Slave Technology FAQ

1. What is the master/slave technology?

The Master/Slave technology is a model for communication and control in various technological systems and processes. In this model, one device or process (master) controls and coordinates multiple devices or processes (slaves) in order to efficiently manage the overall operations of the system.

2. In what applications is master/slave technology commonly used?

Master/slave technology is commonly used in various applications, such as computer hardware, networking, databases, embedded systems, and automation. It can also be found in distributed computing and parallel processing systems, where multiple nodes work together to achieve a common goal.

3. What are the advantages of using master/slave technology?

Some advantages of using master/slave technology include simplified management and control, improved efficiency, and better scalability. By centralizing the control, it becomes easier to monitor and manage the system. Moreover, it allows for efficient allocation and use of resources, leading to optimized performance. Finally, the scalability of this model enables it to be easily expanded to accommodate more devices or processes as needed.

4. Are there any drawbacks or concerns with the master/slave model?

Yes, there are some drawbacks and concerns associated with the master/slave model. One concern is the single point of failure, where an issue with the master may affect the entire system. Additionally, it may lead to potential performance bottlenecks if the master can’t handle the increased load caused by additional slaves. Moreover, the terminology “master/slave” has been criticized for its alleged connotations and many organizations are adopting alternative terms like primary/replica or leader/follower.

5. What are some alternatives to the master/slave model?

Some alternatives to the master/slave model are peer-to-peer, distributed, and hierarchical models. In the peer-to-peer model, all nodes or devices have equal responsibility and communicate directly with each other. In the distributed model, responsibilities and tasks are shared among multiple devices or processes, avoiding a central point of control. The hierarchical model structures the system in multiple layers, with devices or processes having different levels of authority or responsibility.

Related Technology Terms

  • Master Device
  • Slave Device
  • Primary/Secondary
  • Controller/Peripheral
  • Bus Communication

Sources for More Information

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