What Is an HDD?

An HDD is a data storage device that lives inside the computer. It has spinning disks inside where data is stored magnetically. The HDD has an arm with several "heads" (transducers) that read and write data on the disk. It is similar to how a turntable record player works, with an LP record (hard disk) and a needle on an arm (transducers). The arm moves the heads across the surface of the disk to access different data.

HDDs are considered a legacy technology, meaning they’ve been around longer than SSDs. In general, they are lower in cost and are practical for data that does not need to be accessed frequently, such as backups of photos, videos or business files. They are available in two common form factors: 2.5 inch (commonly used in laptops) and 3.5 inch (desktop computers).