1. A method of saving game data of a game, the method comprising: saving two copies of data representing a state of the game to a storage medium; saving a new copy of data representing a state of the game to the storage medium such that one of the two copies is overwritten; checking the new copy of data to determine whether the new copy of data is satisfactory; saving, if the new copy of data is satisfactory, another new copy of data to the storage medium such that the other of the two copies is overwritten; and maintaining, if the new copy of the data is unsatisfactory, the other of the two copies of data on the storage medium.