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 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 TB of storage space.

Basic components of a Hard Disk

A hard disk is comprised of four basic parts: platters, a spindle, read/write heads, and integrated electronics.

>Platters are rigid disks made of metal or plastic. Both sides of each platter are covered with a thin layer of iron oxide or other magnetizable material.

>Spindle - The platters are mounted on a central axle or spindle, which rotates all the platters at the same speed.

>Read/write heads are mounted on arms that extend over both top and bottom surfaces of each disk. There is at least one read/write head for each side of each platter.                                  The arms jointly move back and forth between the platters’ centers and outside edges; this movement, along with the platters’ rotation, allow the read/write heads to                                  access all areas of the platters.

>The integrated electronics translate commands from the computer and move the read/write heads to specific areas of the platters, thus reading and/or writing the needed data.