The PlayStation 2 has a map file that contains all of the exact positions and file size info of the CD in it, which is stored at a position that is beyond the file limit. The game directly calls the position at where the map file is supposed to be. This means that if the file is moved inside the limit, it is useless since the game is looking outside the limit for it, and the file will not work outside of the limit, making any copied disc unusable without a mod chip or the use of FMCB (free memory card boot). FMCB uses the memory card to trick the built-in DVD video software into booting copied games. Before a copied game can be played, it must have been patched with a free application.