You want to remove highly sensitive personal data from a hard disk permanently. Like many other people, you think that emptying of recycle bin or simple formatting of your hard disk can remove data permanently. Well, then you are completely wrong. Data is not removed from the hard disk until is overwritten. Over-writing can take place either through usage of same space on the hard disk or intentionally stuffing it with other data for the purpose of overwriting. If it is not overwritten it can be recovered easily with basic data recovery software. When you delete your files from computer, the operating system merely removes their names from the list of files on the hard disk. Conventional formatting is high-level formatting which just re-initiates the file system from scratch but low-level can provide you deepest levels of data removal. Some of the ways which can used to remove data permanently from hard disk are:-
- Destroying it physically
This method is only feasible if the hard drive is not required for usage, as it will make it completely unusable afterwards. This method is good for hard drives which may not boot up reliably for performing software based erasure of data and can prevent you from any type of data recovery even by forensic analysis by government agencies. First you will have to remove hard drive from your computer. Then you have to remove the screws from the hard drive casing. You will be able to locate silver colored disks which are the platters of hard drive. Try to put deep scratches on the surface of these platters and afterwards smash them with hammer. If you have sledge hammer, it would be easier and would require only few good hits. Other methods like drilling holes through the platters or using high intensity magnets for disturbing the magnetic alignment can also be used effectively.
- Microsoft SDelete Utility
Though not as effective as the above method in removing data, it can save your hard drive for future use. This utility enables you to clean and overwrite unused space on the hard drives. It is often quite difficult to remove file or directory securely in Windows environment. Such vulnerabilities prompted Microsoft to come up with this utility, which may be little difficult to use compared with simple ‘click to delete’, but is much more secure. It can remove bad sectors as well. Just download the utility, unzip it and run it from command prompt.
Command “sdelete –help” can get you a list of all available switches with this command. Type “sdelete -c e:\” to clean free space in E drive of your hard disk.
Apart from these two methods, there are many other methods of removing data permanently from a hard disk. Software like Darik’s Boot and Nuke, CCleaner and Eraser can be used effectively for this purpose. All of them, work on the principle of filling up unused space with new and complex data strings.