Hard disk drive

A hard disk drive (HDD), hard disk, hard drive, or fixed diskFurther inequivalent terms used to describe various hard disk drives include disk drive, disk file, [[direct access storage device (DASD), CKD disk, and Winchester disk drive (after the IBM 3340). The term "DASD" includes other devices beside disks.}} 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. The platters are paired with magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces. Data is accessed in a random-access manner, meaning that individual blocks of data can be stored and retrieved in any order. HDDs are a type of non-volatile storage, retaining stored data even when powered off. Modern HDDs are typically in the form of a small rectangular box.