In the last 20 years, computers have become a vital part of most business operations. As storage capacity and internet connection speeds increase exponentially, paperless offices are becoming commonplace and an increasing proportion of communications is occurring via computer systems.

But as storage capacity increases, so too does the length of time a computer can be in service, and the longer data is stored on a device, the more likely it is that errors will occur and data will be lost.

Hard disk drives, also known as hard disks or hard drives, store data in sections called ësectorsí by encoding it in binary (ones and zeros) onto one or more rapidly rotating magnetised metal disks known as platters. As the platters rotate, data is written and read by a head that is attached to a motor or actuator­ powered arm which moves the head in arcs across the platters.

Damage to a hard drive might be inflicted deliberately, by a malicious employee, for example, or it may occur as a result of overheating due to a fault elsewhere in the computer system. Overheating damages hard drives by warping the platters and causing sectors to become unreadable. Water and fire can also cause damage to the platters, actuators, motor or head, while a heavy jolt could cause the head to come into contact with the platter, resulting in damage to both.

To the untrained eye, it can be difficult to spot a damaged hard drive. If your computer fails to recognise a hard drive, or freezes during boot up, the damage may not be physical, but rather logical, meaning that the problem can be solved without physically altering the drive. However, if your hard drive is making a ticking or a scratching noise, then it is very likely that it is suffering from physically damaged parts.

For computer forensic experts looking to recover data from a physically damaged drive, it may be possible to recover information from the drive by replacing the damaged parts, such as the head. In such cases, an exact image of the drive contents can then be recovered and analysed. However, if the platters are badly damaged, there is sometimes no way to recover the data. If the head of a hard drive has been damaged, every revolution of the platters can cause more damage, so it is vital you do not continue to use a drive if you believe it may have suffered physical damage.

That said, regardless of how serious the damage to a hard drive appears to be, it should not be passed to second hand dealers or sent to public refuse sites unless the owners are positive that the content is unrecoverable. This month is was revealed that researchers from the University of Glamorgan had recovered information regarding intercontinental missiles, bank details and NHS records on second hand hard drives from Europe, Australia and America.

Such findings illustrate the importance of seeking advice from a computer forensic expert before selling or scrapping used hard drives, but they also illustrate that companies need not lose vital data. If damage is suspected, consultation with computer forensic experts can see much of the data recovered and help avoid the potential monetary and reputational expenses associated with data loss.