What Happens to Deleted Data?
Let’s say you have a blurry family picture from the passing holiday you wish to remove from your computer. We all know the basic process of deleting it, whether it be by pressing the delete key or using the right click dialog. To get rid of it for good we’ll head on over to the recycle bin or trash bin and empty it! Upon the swoosh sound of the emptying recycle bin, the thought of the file gone for ever and ever enters our brains.
Is that not it? Is it not actually deleted? What happens to the picture then Mr All-Knowing-One?
Well, to begin slowly, there is a very very important collection of data on your computer called the Master File Table or MFT. The MFT is like a directory for every single file on the computer. When you come along and delete a file, the actual thing you are deleting is the reference to the data in the MFT. So the computer doesn’t know it exists anymore but the file is actually still there in your hard drive. The spot in the MFT where the reference to that blurry picture was is now empty. After a while more of computer use, the space is overwritten and the data is no longer retrievable because new data and a new reference has been inserted.
Why does this happen? Why doesn’t the actual data beneath the reference get deleted upon recycling bin emptying?
There are two very good reasons why there is this extra deletion fluff. One reason is for speed. The actual data isn’t being deleted so emptying the recycling bin is so very much faster than having to remove the MFT reference and the data below.
The second reason is for data safety. It is actually possible to retrieved deleted data from your computer. You have to act quickly but it is possible to recreate the MFT reference and get to data underneath. This is only available if the data hasn’t already been overwritten.
If you lose a very important file and need it back, turn off your computer with slight haste so as to not overwrite to deleted data. If you then bring it in to Computer A Services, we will attempt to retrieve the data lost.