what is a hard drive

A hard drive, also known as a hard disk drive (HDD), is a type of non-volatile storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magnetic material. It is a physical computer component that stores data, including programs, pictures, documents, and the operating system. Hard drives can be internal or external, and they retain stored data even when power isnt being supplied. The primary components of an HDD include a spinning platter and an actuator arm, which moves across the platter to read and write data. The data sectors are spread out randomly across the platter, and the hard drive cover looks like a metal box, which protects the delicate physical mechanisms inside. The primary characteristics of an HDD are its capacity and performance, which are specified in unit prefixes corresponding to powers of 1000. A hard drive is measured in terms of its file size, which can be in megabytes (MB), gigabytes (GB), and terabytes (TB) .