When You Delete, Is It Really Deleted?

Computers are being more close to us day by day. Everything is being computerized. Though most of us know the ins and outs of using them, there is a lot more that we have no clue about.

Deleting a file from a storage device (Hard disk, Floppy Disk etc ;) isn’t needed to be taught to us. Everyone knows how to do it, but do you really know what happens when you do it?

In a normal computer, when you click the delete button, the file is moved to the recycle bin. So later if you need the file back, you can restore it from the bin. Suppose you need to delete it completely from your storage, all you would do is press the shift button with the delete key, and assume as, it has been deleted permanently. Though you assume it has been deleted permanently, that is not true.

Then what does really happen? As you know, computers work with bits (1s and 0s). So when you delete something, what happens is the bits are marked as empty (that new data can be put in there), but it really does not throw away the file from your storage. When a new file is overwritten on the same bits later, then the file is truly deleted, but we the normal users, think that the work is already done before it actually happens. If you have got confidential files, and you delete it just because you think someone would view it, there is still a chance that it can happen even after you delete it. Recovery tools are for that purpose. There are also erasure utilities which simply overwrites the data on top of the deleted data to avoid recovery.

What people are less known is, new technologies can recover data even after it has been overwritten. Overwriting means writing on top of something. So there remains something underneath the overwritten data. So then there should be some way to dig up the hidden data underneath. Though it is possible in some cases, it is not practical for a normal user who does not want to spend millions of rupees just to find some data.

All these information is valid only until the storage device remains magnetic.