I/O Controller

What Does I/O Controller Mean?

I/O controllers are a series of microchips which help in the communication of data between the central processing unit and the motherboard. The main purpose of this system is to help in the interaction of peripheral devices with the control units (CUs). Put simply, the I/O controller helps in the connection and control of various peripheral devices, which are input and output devices. It is usually installed on the motherboard of a computer. However, it can also be used as an accessory in the case of replacements or in order to add more peripheral devices to the computer.


I/O controllers are also known as channel I/O, DMA controllers, peripheral processors or I/O processors.

Techopedia Explains I/O Controller

As CPU speeds increased, so did the need for faster data transmissions between the peripheral devices and the control unit. The input/output controllers work by receiving instructions from the CPU, then sending the instructions to the devices for which they are intended. The I/O controller also manages data communications from the peripheral devices. Thus, I/O controllers save the processing power of the CPU, which would otherwise be wasted while transmitting data. Faster I/O controllers lead to faster CPU communications, which in turn leads to faster processing speed.

The I/O controllers are usually preinstalled on the motherboard of the computer. However, these devices can only accommodate certain common devices. Some unique devices may have a separate I/O controller. Such devices have to be connected to the computer using expansion slots.


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Margaret Rouse

Margaret Rouse is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical, business audience. Over the past twenty years her explanations have appeared on TechTarget websites and she's been cited as an authority in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine and Discovery Magazine.Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages. If you have a suggestion for a new definition or how to improve a technical explanation, please email Margaret or contact her…