what is a disk drive

A disk drive is a device that allows a computer to read from and write data to a disk. The most common type of disk drive is a hard disk drive (HDD), which is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with 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. Disk drives can either be housed internally within a computer or housed in a separate box that is external to the computer. They work by rotating very rapidly around a head or heads that reads and writes data. Hard disk drives and removable disk drives use a magnetic head, while an optical drive uses a laser. A disk drive differs from a solid-state drive (SSD), which has no moving parts and offers greater performance but also costs more and generally offers less capacity.