Testing the limits of hard disk recovery

As our digital appetites increase, so does our need to store our data.

But as we move into the terabyte age with trillions of bytes of storage available for a few hundred pounds, can we rely on hard disk drives to safeguard precious information? And what happens when they do fail or are damaged?

When I had my first computer in 1983 it had 32KB of memory and it was not until 1988 that I had my first hard drive - which had 40MB of storage.

Almost 20 years later and my main desktop can store 160GB of data while my laptop has 120GB and I have a pocket drive with 40GB more capacity.

My back-up routine is poor - I have my music and photos archived on several DVDs but it has been months since I last backed them up.

If the hard drive in my main computer were to fail, I would lose thousands of photographs and hundreds of songs. Every hard drive is a crash waiting to happen and so it is clear I should invest in a back-up storage system.

With 500GB of external hard disk storage available for as little as £89 online and the first terabyte single hard drive released at the start of the year, there is no excuse not to back up.



Inside the hard drive

A recent report from Google engineers suggested that there is no link between heavy use and hard drive failure.

Hard drives less than three years old that are used a lot are less likely to fail than similarly aged hard drives that are used infrequently, according to the report.

However, a Carnegie Mellon University report recently suggested that the failure rate of hard drives used in the business sector was a lot higher than manufacturers' claims.

So what happens if your hard drive fails or is damaged in an accident? To test durability we put a basic 40GB external hard drive through a series of vigorous challenges.

On it we had some photographs and documents and challenged data recovery firm Kroll Ontrack to retrieve our data.

We dropped the drive out of a second storey-window, immersed it in a pond, drove over it and hit it with a hammer.

Was the firm able to retrieve our information?

Rob Winter, chief technology officer at Ontrack, said: "It was very badly damaged and we couldn't recover the data.


Open up the picture to see what happened to our hard drive.

Enlarge Image

"The fundamental reason it wasn't recoverable was that many laptop hard drives have platters made of glass and in this case they shattered. When that happens it is impossible to get the data back.

"Usually laptop hard drives are glass while workstation platters are metal. If the platters had been metal we might have been able to get something back. It all depends on the dents and kinks in the platter."

We went to extreme lengths to damage our drive - too extreme as it turned out. But what are the typical types of damage seen at the firm?

Phil Bridge, managing director at Ontrack, said: "Dropped laptops and spill damage is common. We also see a lot of drives where data has been deleted accidentally.

"In those cases we can typically retrieve 100% of the data."

Mr Winter said: "The first thing we do is make an exact image of the media on the drive. The reason for that is that the drives are often failing or have failed and the best way of preserving the best image we can get is to process the hard drive on to an exact copy.