For the Sega Saturn, Sega's second to last home gaming system, Sega decided to use a unique from of copy protection. Along the outer edge of the discs is a "protection ring". The ring is less than a milimeter. This miniscule ring prevents Sega Saturn games from being successfully copied. Even if all the files from a Sega Saturn game were to be put onto a CD-R, the Sega Saturn would not be able to play the disc as long as it does not have this ring. One methon of getting a CD-R with this protection ring involves manipulating the Sega Saturn itself and more or less having it engrave the ring onto a CD-R. I would not advise this method, as it is said to "ware out the system's engine". If anyone knows any better methods, please let me know.