I think all the data recovery software works on the same principle. If you pick up the software and it does provide the recovery then that utility is the hero as it has save our work worth million dollar. For instance I would say my hero is Stellar Phoenix Windows Data Recovery Software as I picked this utility to recover my missing data and it did convince me recovering almost 100% of stuff. But have we ever though of on what principle these software work. If any body know then please share with us.