What is ISO?
ISO is a disc image, its exact copy, saved as a file. Sometimes in addition to image there are also game music files enclosed to it in WAV or MP3 formats. ISO images are created with special programs, such as CDRwin, UltraISO, Nero, etc. In this form games for CD consoles, such as Sega CD, Sony Playstation, NeoGeo CD are stored. Image can be used for running it with emulator or as a true copy of original CD for burning it onto CD.