Datlabs the Hard Drive Failure Specialists.

Datlabs research and development projects have facilitited a knowledge of hard disk storage media and hard drive technology fundamental to establishing a professional data recovery service operation. This knowledge coupled with major manufacturer relationships and experience means we are able to recover data from all category of failed hard disk drives.

Modern Hard Disk Drives:

A hard disk drive is a device which stores your data and programs on rotating disks that have been coated with a high permeability magnetic material. Data is recorded by creating magnetic patterns in the material. These patterns are retained when electrical power is removed or switched off. (This is termed non volatile magnetic storage). The data patterns are made and detected by a dual purpose component called a read-write head assembly. This assembly rapidly switches magnetic polarity in response to electrical signals when writing information to the platter surfaces and amplifies and tidies up the signals into recognisable data streams when reading. In modern hard disks the recording platters rotate at speeds of 10,000-15,000 rpm.

The read-write head assembly is aerodynamically designed to float during operation above the rotating platters on an air cushion at a distance of a few nano meters. These exceptionally fine tolerances coupled with high rotational speeds leave the device susceptible to damage due to knocks, environmental extremes and wear and tear. If you have a problem:-

The chances of hard disk drive failure increase greatly during extended periods of use , transportation and environmental extremes such as temperature variations. Rotational speeds of 15,000 rpm, generate relatively large centrifugal forces and any single adverse affect, i.e. knocks, movement and temperature extremes will and do cause severe hard disk failures.

The most commonly occuring industry hard disk drive failures can be generally classified into two categories. The first is physical failure, which is when the internal components of the drive have been physically damaged. The second is firmware or bad sector damage, which corrupts the data such that it becomes inaccessible and affects the operation of the drive.

The failure symptoms in both cases can be similar and result in a head actuator mechanism clicking sound.

If you have a "clicking" hard drive then get in touch for friendly assistance:-

Causes of hard drive failure:

• Head crash.
• Firmware corruption.
• PCB component malfunction.
• Mechanical Failure.
• Failed Operating System.

Hard Disk Drive Head Crash:

Of the failure causes listed above, by far the most common type diagnosed by Datlabs technicians is a "head crash." The growing market for mobile computer and data storage products leaves the installed hard drive vulnerable to knocks and shocks that cause the head assembly to "heavily" contact the surface of the platters.

What we loosely call a "head crash" is the malfunction of the read-write heads resulting in a buzzing or clicking noise.

What Is A Read-Write Head?

A read-write head is a tiny electromagnet suspended by an armature that is precisely positioned above every disk platter and normally covered by a ceramic material. The head acts as an interface between the physical storage media and the rest of the electronic components of the disk by transforming electrical signals into magnetic pulses to store data onto a disk. In reverse, it reads the patterns of the magnetic flux and converts them into electrical signals which are further encoded into binary bits to be processed by the computer.

How Does A Head Crash Happen?

When the platter is rotating at rates of anything between 5,400 to 15,000 revolutions per minute, a thin flow of air suspends the read/write head extremely closely above the disk surface. This distance, called the head gap is typically measured in millionths of an inch. So, it is possible that heads can make contact with the media on the hard disk when there is a violent vibration or there is a faulty actuator mechanism.

Head Assembly Parking.

When the drive disks are not rotating , the read write heads ress on the surface of the disk or on a parking bay. When the disk powers up and the platter starts to spin, the head momentarily rubs along the surface of the platter before a cushion of air is created that allows them to hover above its surface. During a power down the process is reversed. A landing zone or an empty track has been created and set aside for the head to take-off and land as a "landing strip". This safety area and process is known as the" parking technology". In the event of a power loss or power down of the disk, a retract mechanism moves and secures the head assembly to this landing zone.

When the disk powers up again the assembly unparks itself . Similar techniques of load/unload also apply when a ramp-like mechanism is used to lift the head from the disk surface and park it off the platter surface.

Drive Enclosure Contamination.

A hard disk is never 100% sealed. If it is, then it is not possible to create the necessary air flow for the disk working mechanism. When dust enters and contaminates the hard disk, it can obstruct the movement of the head, resulting in a crash as the clearance between the head and platter is by far smaller than the size of a smoke particle.

Hard Disk Drive Knocks and Shocks.

A shock applied to a hard disk drive while it is in active state may cause the head to bounce and slide against the platter causing it to burn-out or scratch the platter surface.

Hard Disk Drive Component Wear.

Hard disks are complex and extremely delicate electro-mechanical devices subject to wear and tear over time. They have a fairly predictable lifespan even within a controlled environment, just like other mechanical devices. Wear on bearing mechanisms and moving parts will cause vertical movement of the heads outside of its acceptable tolerance range and potentially crash the read write heads on the platter surfaces.

Design Features vs Hard Disk Crashes.

Hard Disk Drive platters manufactured today are guarded with anti-vibration mechanisms and head parking technology designed to prevent the head from making contact with the rotating platter when a drive is shocked or jostled. Protective layers are also implemented on the magnetic surfaces of newer disks to withstand a marginal number of head crashes before permanent damage sets in. For instance, laptop computer hard disks are manufactured with a greater shock resistance capability However it is always recommended to avoid moving your computer or external disk whilst the disk is still in operation.

How Does A Head Crash Occur?

When the platter is rotating at rates between 5,400 to 15,000 revolutions per minute, a flow of air suspends the read/write head extremely closely above the disk surface. This distance, called the head gap is typically measured in millionths of an inch. So, it is possible that heads can make contact with the media on the hard disk when there is a faulty disk mechanism.

Bad Head Parking.

While the platter is idle, the head typically rests on the surface of the disk or on a parking mechanism. When the disk powers up and the platter starts to spin, the head rubs along the surface of the platter briefly before a cushion of air is strong enough to hover the head above its surface. During a power down the process is reversed till the platter finally stalls. This cycle of normal use is after a prolonged period of wear and tear likely to cause a head crash. Hence, a landing zone or an empty track is set aside for the head to take-off and land. This safety process is known as the parking technology and is designed to protect against the possibility of data damage. In an event of power loss to the disk, a retract mechanism moves and secures the head to its landing zone without the use of external power. It then automatically un-parks itself when the disk powers up again. Another similar technique is the load/unload technology which uses a ramp-like mechanism to lift the head from the disk surface and park it outside of the platter.

Dust and Particulates.

A hard disk is never 100% air tight. If it is, then it is not possible to create the necessary air flow for the disk working mechanism. Any particulates or dust entering the internal space will contaminate the hard disk and impede the correct operation of the heads, potentially causing contact with the platters as the clearance between the head and platter is smaller than the size of the particles.

Read more about hard disk failure here...