Simply deleting the contents of a hard disk is not enough to ensure that they are not recovered. In fact, there are software utilities that allow the recovery of deleted data. This possibility is because when a file is deleted, it is not actually overwritten or removed from the hard disk. Instead, a marker is just associated with the file to say that it has been deleted, and the space it occupies on the disk is marked available for use. This means that the data in the file remains on the disk for the knowledgeable hacker to extract and view.