Head faults - Recovering data from noisy / clicking / ticking hard disk drives

Head faults - Recovering data from noisy / clicking / ticking hard disk drives

Symptoms: When the computer is powered on, the hard disk -
(1) Will not be recognised by the computer and
(2) A ticking or knocking sound will be heard coming from the hard disk at regular intervals (often about 1 / second).
An error message similar to "Hard Disk not found" or "No system disk present" will be displayed, and the system will then halt.

Hard drives with these failure symptoms are often indicative of an internal failure of one or more of the read / write heads in the hard disk assembly. This type of failure is found with both desktop and laptop hard drives. Fortunately, if the correct recovery processes are applied, data from hard disks with these failure symptoms is often recoverable.

What is happening when the hard disk makes a ticking sound ?
Data is written to / read from the hard disk platter surface by a read / write head which is located at the end of an arm that moves across the hard disk platter surface when the disk spins. A faulty hard disk that produces a knocking sound is likely to have a fault on it's read / write head. The knocking sound you can hear is caused by the arm of the hard disk knocking against other components in the hard drive.

Example:
The movie below shows a laptop hard disk with a head failure. We have removed the cover of the hard disk so you can see what is happening internally.
(1) First of all, the disk powers up and the platter begins to spin until the correct rpm is reached
(2) The arm containing the read / write head then moves out onto the platter surface and attempts to read some basic information from the hard disk. However, because of the faulty head the disk is unable to read the data correctly.
(3) The disk then resets itself and attempts to re-read the data. This stage is repeated a number of times and is what produces the knocking noise.