What's inside a computer?
( 1990 ) A hard disk is a magnetic device that can read and you can write information. Information is not lost even when the power is off.
A hard disk is a permanent external store of computer information. It stores operating system files, programs and data, and user-generated documents. Disk capacity is measured in terms of gigabytes (1GB = 1000 MB). A desktop PC hard disk can store as much information as thousands of CD-ROMs or tens of thousands of floppy disks. The data transfer rate is thousands of times faster than for floppy disks.