Ramp : The component to rest the read-write head when hard disk drive stops working. It also provides smooth movement of read-write head once the hard disk drive start working again. Crash Stop : The crash protection component for read-write head. It works while the head is moving toward the confinement. Latch : The locking component of read-write head set. It works after the head parks with Ramp when hard disk drive is going to stop working.