A method and system for saving and retrieving data includes saving data in data storage fields of a data storage device in a computer. A back-up data storage field is selected in the data storage device. A data changing operation including new data is initiated on specified data saved in a current data storage field. A copy of all the data stored in boundary data storage fields is copied and stored in the back-up data storage field before changing the current data to provide data retrieval if the data is unrecoverable in the current data storage field, when a loss of power to the data storage device occurs.