A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage and one or more rigid rapidly rotating platters coated with magnetic material.

Hard Disk uses magnetic storage to store and retrieve digital information. That is why it is also called Electro-mechanical data storage device. The hard disk consists of one or more circular rotating disks to store the data. Each platter has a very thin strip, which is made using magnetic material.

A computer’s hard drive is a device consisting of several hard disks, read/write heads, a drive motor to spin the disks, and a small amount of circuitry, all sealed in a metal case to protect the disks from dust. In addition to referring to the disks themselves, the term hard disk is also used to refer to the whole hard drive.