Clicking and noisy hard drives explained

During normal operation and from model to model some hard drive noises can be heard either when the disk is being accessed or sometimes even when the drive appears to be idle, these are normal and in line with operational performance of the hard drive.
Loud repetitive clicking, ticking, scratchy or rhythmic noises from the hard drive usually are an indication of imminent or actual failure of the hard drive which should be switched off immediately.

What is causing the noise?
Two components make up for the noise heard from the hard drive first there is the spindle motor and bearings which these days employ fluid dynamic bearings (FDB) which reduce noise considerable then there is the head stack assembly (HSA) which is driven by the voice coil motor (VCM) it is this components that creates the knocking, clicking or noise from the disk.
When the disk is powered on the spindle motor starts up the platters reach there designated speed such as 7200 RPM then the VCM releases the HSA to scan the platter surface and look for specific areas of the surface such as servo wedges and marks, tracks, calibration data and other unique data for that particular drive.
Surface damage can impede the location of these vital areas thus causing the HSA to repeatable look for those signals thus creating the repetitive clicking noise from the drive, the HSA may also be damaged which can be broken down into two main areas such as the actual heads and the preamplifier section, again if these are damaged no signal is being returned to the printed circuit board (PCB) and will cause a temporary loop to occur, of course the firmware and CPU on the PCB will allow for X number of retries before timing out and returning the HSA to the park position.

Firmware damage can also cause this failure type such as noisy or clicking and is caused because even thought the media surface is alright and the HSA operational the specific data for the drive can not be found and cause suspected physical damage this section requires specialist tools and knowledge and can easily be mistaken for issues mentioned in the previous paragraph.

What are the specific causes?

Specific causes to noisy hard drive storage media are broken down to internal and external influences.
We have discussed HSA failure briefly however this can be broken down into actual specifics such electrical over voltage entering into the HSA, excessive heat damage to the HSA, and the finite and mean time between failure (MTBF) with the start stop and hours breaking the HSA physically down.
Surface breakdown the magnetic properties of the media due to entropy and heat related issues.

How can the data be recovered?
Noisy hard drive Media rarely can be dealt with by home users in fact many IT departments do not have the required tools and knowledge to recover data with such failure types and certainly if the storage devices has valuable data then it should be handled by any other company than a professional data recovery company.
Software solutions will not help and in many situations will actually destroy the data as leaving the drive running in this format will compound or destroy your data surfaces.

Professional data recovery services.

In most circumstances a professional data recovery company will recover your required data using specialist tools, equipment and knowledge which might include replacing failed compo nets such as the HSA which is not as easy as it might sound as for instance there are many different permutations for HSA from model to model and even though a n identical model of drive is located to used as a donor drive for the failed components the actual HSA may differ considerably and must be matched exactly the procedure will fail.
Firmware revisions also can change on a day to day basis and from factory to factory again precise information and matching must be adhered to if a successful recovery is to effected and the required data recovered.
The cost of this type of service must be weighed against the value of the data if it is sentimental data then that is difficult to quantify, however when it comes to business data that is a much easier scenario, how much is the loss of accounts data say from the last year from a clicking or crashed hard drive? Only the company would know this but this can easily derived from what if any paper trail you may have, and the size of the business.