Non-DOS (or NDOS as they are referred to) use their own custom file system, allowing the game to be loaded faster than AmigaDOS disks and make it slightly more difficult to copy. By default they cannot be accessed by AmigaOS. However, there are utility programs available from Aminet that can create non-AmigaDOS partitions on your hard drive. There are also patches available that make an image of the disk on your hard drive and allow the game to be run. Patches can be found on Aminet as well as http://www.fh-zwickau.de/~jah/ Fortunately, most new games come with their own installers now that hard drives are common so it is doubtful that you will need a patch to run a recent game.