An actuator is a device that controls the actuator arm by conducting electricity into a coil, which is a voice coil motor coil.
It reads slowly because it moves one step at a time, and when it does not turn on the power while it is reading, it stops there, causing the hard disk to be scratched with a knife when it works. However, it has an automatic parking system.
Actuator Arm
The actuator arm moves horizontally across the platters to read and write data. The actuator axis is located at one end of the actuator arm and is in the middle. Cover mounting holes are places where screws are installed to cover the hard disk.
Head
The head is actually the read/write head. This head can read and write data. Each platter has two heads up and down. Two platters will have four read/write heads.