The hard drive, or hard disk drive (HDD), is the device inside your computer that allows you to permanently store data. The hard drive is a mechanical device that has rotating platters inside of a sealed case. Digitally encoded data is stored on and retrieved from the magnetic surfaces of these platters via a moving actuator arm with read-and-write heads on it. Since the data is stored magnetically, you should never allow magnets near a hard drive. Or else your data may become corrupt. Since a hard drive is a mechanical device, something will eventually go wrong with it and it will die. Because of this, you should always keep backups of important data in a safe place