Think of the time you take to copy a 1 GB file to the hard disk drive and the time taken to delete the same file. Doesn’t it take very less time to delete it compared to the time you took to copy it? This implies that the file is not completely deleted from your computer. It is still present in the computer and so we can recover it. Almost any deleted or corrupted file is hence recoverable.

Data Recovery is the process of retrieving damaged, failed or corrupted data when it cannot be accessed normally. Recovery may be required due to physical or logical damage to the file system that prevents it from being loaded. Data recovery can also be the process of retrieving and securing deleted information from a storage media for forensic purposes or for spying.

Common causes of data loss are the following:

• Electronic Failure
• Natural Disaster
• Computer Virus
• Data Corruption
• Computer Crime
• Human Error

Hard Drives are an amazing piece of mechanical engineering, as they spin at around 120 times per second. These spinning platters are spinning at such high speeds that a small interference whilst in usage can damage the disk in a certain area. When some areas of the disk fail, the hard drive is effectively useless. There are softwares available which helps to recover all deleted files and folders from your hard disk drive and restores your crucial data back. But this is only possible when there is no damage to the media and when the data is not over written. Very few software programs understand damaged media.

When data is written onto the disk drive, the head sets the polarity. The software uses this technology, by reading the signal from the analog head electronic, with a high quality digital oscilloscope. Then it downloads the sampled waveform to a pc. Finally, it is analysed by the software to recover previously recorded signal. There are mainly two recovery methods:

Scanning Probe Microscopy (SPM) which uses a sharp magnetic tip attached to a flexible cantilever close to the surface to be analyzed, where it interacts with the stray field emanating from the sample to produce a topographic view.

Magnetic Force Microscopy (MFM) is for imaging magnetization patterns with high resolution and minimal sample preparation and this is based on SPM technique. This technique uses a sharp magnetic tip attached to a flexible cantilever placed close to the surface to be analyzed where it interacts with the stray magnetic field. An image of the field at the surface is formed by moving the tip across the surface and measuring the force as a function of position. The strength of the interaction is measured by monitoring the position of the cantilever using an optical interferometer.

One of the most important points for any computer user to remember is to always back up your data. Sometimes a hard drive can be partitioned into several drives that appear on the computer. In this case all data is most likely not lost and it will probably be recoverable with a little work. If your hard drive makes ill-sounding mechanical failure noises (loud clicking, rattling, scratching), then back up your data as fast as possible and buy a new hard drive.