What data can be recovered and why does it matter? Files that are written to the hard drive make themselves a far more permanent presence than many people realize. When deleted-accidentally or deliberately there may be a reason to try and recover them in the future, or to fear that someone else might try to.
To understand why it is that files can be recovered after they have been deleted, it is important to first understand how the data in that file is stored. There are essentially two separate parts to file save. One is the set of data itself, which may actually be written to a number of different sectors on the hard drive, especially if the hard drive is already particularly full.
The other half of the file save is an address. It is a far smaller file that tells the computer where to find the data on the disc that it needs in order to return that particular file to the user. It could be considered akin to the house number and street address that are associated with your house and that tell people where to find you.
When the file is ‘deleted’ all that actually happens is that the address is deleted. The data itself remains, intact and unchanged until another file happens to be saved to that location on the hard drive. This can be compared to your street sign and house number being pulled down. People would have a hard time finding you, but your house would still exist exactly as it was before if only they knew where to look for it. Similarly, data recovery software can scan a drive and add new ‘address’ labels to the deleted files.
The main reason that you may wish to consider the fact that data can be retrieved is that you may one day wish to sell or donate an old, used computer. It is essential that you adequately handle the personal data that might be stored on your computer. Specifically, you would not want your banking information to be accessible by the person who ends up with your computer, and so you need to take steps to protect yourself. There are computer programs available that will destroy your hard drive data for you, leaving the hard drive itself clean and ready to be used by the computer’s new owner. Software such as this will delete and then overwrite your files multiple times, to make recovery as close to impossible as it can be.
An alternative is to simply buy a new hard drive and put that into the computer in the place of your old one. They are now available for very reasonable prices, and are easy to fit. The previously used hard drive may be kept as a spare for use in another computer that you own, could be mounted as a secondary drive in another computer, or may be destroyed altogether by physically smashing or burning the drive.
The ease with which files on a used hard drive can be recovered will vary. However specialist software that can be bought can help to ensure the privacy of your personal information.