In windows OS, the file allocation table is used. It tracks down the location of the file and files that are stored on the hard drive. It is the same as the table of contents of the book with the difference that pages are the files. When the data is lost and it demands to be retrieved then there is some problem in the file allocation table.
The files that are to be recovered are still on the hard drive. The file can be recovered if it is undamaged and is present on the hard drive. If the data files are missing or damaged then some other techniques can be used to recover them. Even the physically damaged hard drives can be reconstructed to get the data back. Many technologies and processes are combined to recover the data. It is not recovered alone by restoring the data from the tape. This recovery process takes time for some data and the applications.