What is a hard disk?

A hard disk or drive is the part of your computer responsible for long-term storage of
information. Unlike volatile memory (often referred to as RAM) which loses its stored
information once its power supply is shut off, a hard disk stores information permanently,
allowing you to save programs, files, and other data. Hard disks also have much greater
storage capacities than RAM; in fact, current hard disks may contain over 19 GB of
storage space.