Updated: 04/02/2019 by Computer Hope

An actuator is an electronic device controlled by a motor that moves the hard drive head arm. In the past, the actuator within a hard drive was controlled by a stepper motor. However, today the actuator is often controlled by a servo motor. Below is a graphic example of the inside of a hard drive including the head actuator.

Inside a computer hard disk drive


An SSD (solid-state drive) doesn't have moving parts or a motor.

Click of death, Hard drive terms, Read/Write heads