There's quite a lot of info online about the original PlayStation copy protection and 'wobble' in the pregap, but I'm struggling to find anything definitive about the PS2. How did it detect burned discs and how did mod chips get around the protection? All I can find is a lot of wild speculation in ancient forum posts, nothing that really explains it. The best I can come up with is this single sentence on this Wikipedia page. "A map file that contains all of the exact positions and file size info of the disc is stored at a position that is beyond the file limit. The game calls this place directly so that burned copy with no data beyond file limit cannot be played." Is that correct? Can anyone expand on that?