Headered ROMs

Headers have information about the original ROM data. Such information is used by emulators.

Most emulators can only run ROMs with headers, but unheadered ROMs exist for archival purposes.

Examples of additional information given by headers: size of the ROM, region, name of the game, version, mapper, byte order (big endian, little endian, interleaved), system (arcade or home), presence of additional hardware in the cartridge.