Now that we have talked about all of the parts that are easy to identify and to see, it is now time to zoom in and take a closer look at the head stack itself. You will find many of the most interesting aspects of the head stack are found at the end of the arm, where the head itself is located.

Lets start off with a picture:

The end of the arm

The first part you are going to notice is the black square near the end. Many people actually mistake this component as the head when actually it is not.
This component is actually called the “Slider”. You can see that it has some grooves in it, which are designed to make the slider aerodynamic. This allows for it to glide on the “Air bearing” that is created by the rapidly spinning platters. This is how the heads manage to not touch the disk surface.
The gold wire coming from the arm is the “lead”. It is the connection between the heads themselves and the preamplifier.
The heads are located at the far end of the slider. They aren’t clearly visible in this photo, but you can see where the leads curve around and go back towards the slider. The heads are where the leads end. The average flying height for heads on current drives is 5-10 nanometers. In comparison, a strand of human hair is approximately 60000 nanometers in diameter. A DNA molecule is ~2-12 nanometers wide.
Newer hard drives are utilizing a sort of “Dual actuator” technology. They use a Piezo electric system where an electrical charge is provided to the material, which causes it to be manipulated in the direction needed with extremely high precision (within a nanometer or so).
The next and final installment of this series on the HSA, I will detail how the heads read and write data.

Bookmark