For any kind of data to be processed by the digital machines, it has first to be converted into a digital form, which is nothing but a string of ones and zeros. The processor has millions of microscopic transistors that are capable of a phenomenal number of calculations per second.
The data processed by the digital device has to be stored somewhere. There are a range of digital devices available in the market at all price points that are used for the storage of digital data. These range from floppy drives with a 1.2 MB capacity to hard disks that can store as much data as 500 GB! The storage devices use different techniques to record data on the storage surface.
A hard disk has a number of platters coated with magnetic paint on which data gets written by the electro-magnet of the read / write head. A floppy drive and tape drive use similar technology to store data. Then there are optical disks which use a laser to burn a pattern of pits on the data-recording surface. The laser bounces off the disk surface back to the drive lens, thus allowing the operating system to access the data.
The storage devices have a fixed life of some years after which they have to be discarded. But this poses a problem. The devices have valuable data recorded on them. How to ensure that the data gets deleted permanently so that it does not fall into wrong hands after you have thrown the storage device away? Many users have a simple solution – just hit the delete button and you are done with the whole thing. Nothing actually can be further from the truth.
Not many computer users realize it but merely deleting the data does not ensure its erasure. What actually happens is that when you give the delete command for a file, the operating system frees the storage surface where it resides for storing a fresh set of data. The file is very much there on the device but it merely becomes invisible to the operating system and hence the user. The file, as long as it does not get overwritten with another file, can easily be extracted using any commonly available Do-It-Yourself data recovery software.
The same thing happens when you reformat the entire storage media. When you give the reformatting command, the operating system merely deletes the file allocation table which records which file is lying where on the data-recording surface of the device. The entire surface is then made available for recording a fresh set of data. However, the device still contains all the files, which can be easily recovered by anyone.
So neither deletion nor reformatting can delete the data permanently. Many users do not realise this and end up throwing away their storage devices such as hard disks, tape drives and optical disks into the bin or sell them at a pawn shop. This can have serious implications.
Every year, scamsters are able to recover from discarded storage devices confidential information such as passwords for Internet banking, credit card numbers, bank details and personal information such as addresses, family pictures, health history, financial records and so on. There is actually a full-fledged industry of crooks that just rummages through old storage media to find out some information that can be misused.
The only solution to this situation is to destroy the stored data permanently. This can be done in many ways. There are many commercial data-overwriting software available in the market. These exploit the fact that data can be permanently erased if it gets overwritten many times. The software, therefore, overwrite your entire storage media seven or eight times with gibberish. After this, even the world’s best data recovery technicians will be unable to recover even a byte of data.
The other way is to physically destroy the data-recording surface or the entire storage device itself. For a hard disk, the best way is to pour acid or some corrosive substance on the data-carrying platters. Some people hammer the disk out of shape or even drill holes into the platters. Optical disks such as CDs and DVDs can simply be smashed to bits, while the plastic tape or tape drives can be burnt to ashes.
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