Erasing Data Permanently By: James Walsh

If it contains sensitive information such as your bank account details or financial statements, intimate pictures, videos, etc. and falls hard into the wrong hands, you might be in deep trouble. 

There are some people who understand these implications and try to delete all the personal information on the computer, clear the recycle bin and even perform a reformat and reinstallation before giving away their computer. However, they do not realise that these procedures cannot completely erase the data present on the hard drive and an expert would still be able to recover data present on it. 

What Really Happens When you Erase Data?

When you delete data from your computer, you might not be able to access the deleted information although it might very much be present on the hard drive. So, what really happens when you erase the data? In order to understand this, we need to know a little about hard drive functionality.

When you store data on a hard drive, it might be broken into smaller units and stored on different locations of the hard drive. Each location is given a unique address and the data is accessed using this address. When you try to delete a file, it frees up the location containing the address of the file rather than deleting the file itself. This means that, your data is still present on the hard drive until it is rewritten by fresh data. However, in the meantime, when you try to access the file, your computer will not be able to locate it since it has lost the address. Even after reformatting or reinstalling of the OS, your data might still reside on the hard drive. 

Although the computer cannot normally retrieve these deleted files, the data can still be recovered with the assistance of data recovery software or a recovery expert. This applies for data present on your hard disk, optical media, USB drive or any other storage device. 

Ways to Permanently Erase the Data

So, how can you safely dispose your used hard drive without compromising your data? There are actually a lot of ways of getting rid of the data forever. A few of the most effective and feasible techniques are given below:

1. Overwriting the Data: As we have already discussed, the data resides in the hard drive until it is overwritten. So, in order to get rid of it, you can overwrite your hard drive completely with some useless or dummy data. Try to repeat the process a few times in order to make sure all your data is completely wiped out. 

2. Using Software: Instead of going through the process of overwriting the data on your own, you can use special software designed for the purpose. Deletion software sold on the Internet can completely wipe out the data. 

3. Degaussing: Since, the data is stored on the disk through magnetisation, degaussing is an effective way of removing the data. In this method, a reverse magnetic field is applied to your hard drive that disturbs the magnetisation of the disk and erases all the electronic data. Once degaussed, the data becomes completely unreadable. However, this is a costly procedure and is more suitable for corporate. 

4. Physical Methods: If you are planning to scrap your hard drive instead of selling or donating it, the best option would be to cause physical damage to the hard drive. This way computer would not be able to access or read any information present on the hard drive. In order to destroy the hard drive, you could drill four or more holes on the hard platter and scratch the surface till the coating on the platter is gone. There are also people who try to smash the drive with the hammer, destroy individual platter, shred it, etc.

However, while trying to destroy the media physically, make sure you are wear protective glasses; wrap the device in a cloth before breaking it and take all the necessary precautions to avoid any dangers. Considering the safety measures, it is better to wipe out the data rather than trying to physically damage the media. 

The Last Word

So, next time you think that a fire, flood or any other problem has caused the failure of your storage media, do not just throw it away. Even if you have sent the drive to a data recovery expert, be sure to get the media back even if they claim that the data is unrecoverable. Take every precaution to wipe out the data before disposing it. It can save you from financial losses or embarrassments in the future.