An ISO file, often referred to as an ISO image, is an archive file that contains an identical copy (or image) of the data found on an optical disc, like a CD, DVD, or Blu-ray disc. It essentially represents the entire contents of the disc, including the file system, boot information, and all the data files, in a single file. ISO images are commonly used for backing up optical discs, distributing software, and creating virtual drives. They provide a convenient way to store and share large amounts of data without the need for physical media. The ISO format preserves the original disc's structure and content, ensuring that the data can be accurately reproduced when burned to a new disc or mounted as a virtual drive. This makes them ideal for distributing operating systems, software applications, games, and other types of data that are typically distributed on optical discs. The file extension '.iso' is universally recognized as representing this type of disk image.