INTERNAL COMPONENTS OF A LAPTOP HARD DRIVE

The delicate internal components of a laptop hard drive are shown below and explained with detail.  A hard disk should never be opened unless in a clean room environment. 

Drive Casing
The drive casing is the rectangular shaped box housing all of the internal components of the laptop hard drive.  A cover mounts to the casing using multiple screws (for the illustration above, the cover has been removed).

Actuator Arm
The actuator arm (also called the read/write arm) contains read/write heads near the end of the arm (see close up photo
above).  The read/write arm positions the read/write heads at the correct location on the platter to read the data.  The heads never touch the disk platters when accessing the data.  They function at 5 microns above the surface of the platter. 

Disk Platters
Platters are the circular shaped objects in the center of the casing which hold all of the data on the hard disk.  A disk can contain one or more platters depending on the capacity.  Platters are round with a hole in the center- similar to a record used on a record player.  A spindle with a motor holds the platters together and rotates them at a certain speed measured in RPM (revolutions per minute).  This creates air pressure that lifts the read/write heads off the platters.

Actuator
The actuator moves the arm to the correct position on the platters using voice coils motivated by electric currents.  When no electric current is being received, the actuator causes the actuator arm to place the read/write heads in the parked position.