The main purpose of a hard disk drive is to operate as a storage device for data. A hard disk stores data internally by recording it on metallic plates that are charged electromagnetically. As of 2015, hard drives can store many gigabytes of data.
A hard disk that resides inside a computer is typically stored in a drive bay and is connected to the motherboard using either a SCSI, SATA or ATA. The hard disk is also powered through a direct connection with a power supply unit inside the computer. The first hard disk was released on Sept. 13, 1956.