Layout of HDD

Introduction

A hard disk drive (HDD) is a nonvolatile storage device used in computers that persists data in a durable way. IBM introduced HDDs in 1956, and they have since become the dominant secondary storage device for general-purpose computers.

Components

Let’s take a look at the different components of an HDD and their roles.

Platter

An HDD consists of one or more circular magnetic plates, called platters, stacked over each other to hold the data. Each platter consists of a nonmagnetic material such as aluminum, glass, or ceramic, coated with a shallow magnetic material 10–20 mm in depth and an outer layer of carbon for protection. Each platter has two working surfaces, one on either side, which holds the actual data.

Spindle

The stack of platters is held together by a spindle motor, which is responsible for controlling and rotating the platters. Most HDD failures are related to the spindle's inability to spin the platters.

Actuator

Each platter has an actuator arm positioned on top of it, which is responsible for reading, writing, and deleting the data on its respective platter. Actuator arms are also called read-write arms.

Read-write arms have two separate heads:

• The read head: Responsible for reading the direction of magnetic current and converting it into bits.

• The write head: An ...