A rigid magnetic disk that is able to store many times more data than a floppy disk. Usually it cannot be removed from the disk drive that's located inside your PC. In most PCs the hard disk drive is called drive C:, whereas the floppy disk drive is called drive A: or B:. A hard disk drive can normally store several hundred million bytes (or characters) of information, whereas a floppy disk can only store one and a half million bytes. If you hear a clicking or whirring sound when you save a document, that's the hard disk working.
