An external hard disk drive (HDD) or solid-state drive (SSD) is a data storage device that connects to a computer via a USB cable or other interface. External hard drives provide additional storage space for computers and laptops, allowing users to store large files, such as movies, music, photos, and documents. They are also useful for backing up important data in case of a computer failure or data loss.
External hard drives come in a variety of sizes, capacities, and speeds. The most common sizes are 2.5 inches and 3.5 inches. The capacity of an external hard drive is measured in gigabytes (GB) or terabytes (TB). The speed of an external hard drive is measured in revolutions per minute (RPM). Higher RPMs indicate faster data transfer speeds.