Fact Checked

What is a Master/Slave Relationship?

R. Kayne
R. Kayne

Master/slave technology is part of the legacy Parallel ATA (PATA) standard. ATA stands for Advanced Technology Attachment and is available in a newer serial flavor known as Serial ATA or SATA. The newer standard has many advantages over the PATA setup, but PATA is still in wide use in older systems.

The master/slave relationship is part of a transmission protocol that bridges communication between a hard disk and the motherboard it's attached to. In this type of setup, a flat, wide parallel cable runs from an interface on the motherboard to the hard drives. Each parallel cable has two female ports to accommodate up to two drives. The primary port connects to the master drive, the secondary port to a slave drive. The master drive is the boot drive.

A computer motherboard.
A computer motherboard.

When installing two PATA drives on a single parallel cable, each drive must be configured with a jumper to designate it as the primary or secondary drive, master or slave. Failure to set the jumpers will prevent the system from recognizing the drives properly. The parallel cable itself might also be labeled as to specific master and slave ports. Information about these designations in a system is available within the motherboard’s BIOS menus.

Information about master/slave designations can be found in the BIOS menus.
Information about master/slave designations can be found in the BIOS menus.

While the initial versions of SATA were comparable to speeds of advanced versions of PATA, the serial cable allowed the speed barrier to be quickly surpassed. Unlike parallel cables, serial cables are narrow and unobtrusive, allowing for better airflow inside the system case. SATA also uses a dedicated interface and cable for each drive, eliminating the two-in-one master/slave standard of PATA. SATA drives do not need to be jumper-configured and are plug-and-play, unlike PATA drives.

Before purchasing a hard disk, individuals should be sure to check if the interface is PATA or SATA. Consumers should note that PATA drives can be found inexpensively and can be a good choice for an external archive drive, even if the system drives are SATA. Systems can also generally handle a mix of internal SATA and PATA drives, though this would not be ideal for a RAID array, as the PATA drive would slow it down. Computer users should check their motherboard manual for specific information about the capabilities and interfaces available on their system.

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Discussion Comments



This is a good point, and it is also likely that the technologically savvy and computer geeks recognize that they can name things with impunity as they so please because they have a skill that is in high demand and receive automatic respect for their expertise.


The naming of these software bits and various technological functions is dubious and sometimes rather strange. For example, the usage of "male/female" bits to describe plugs in a sexual manner, causes some people to scratch their heads. This "master/slave relationship" is also questionable, but it is likely that, due to the layman's lack of understanding of technology, people simply assume that it has some deeper meaning.

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    • A computer motherboard.
      By: VIA Gallery
      A computer motherboard.
    • Information about master/slave designations can be found in the BIOS menus.
      By: Aaron Parecki
      Information about master/slave designations can be found in the BIOS menus.