ISO 9660 is a standard file system for optical disc media, primarily used for CD-ROMs. It was developed to ensure that data stored on CDs can be read across different computer systems and platforms. The standard defines how data is organized and accessed on the disc, allowing for compatibility with various operating systems. The ISO 9660 format supports a hierarchical directory structure and file naming conventions. It also includes extensions, such as Joliet and Rock Ridge, which enhance its capabilities by allowing longer file names and additional file attributes. This makes it easier to store and retrieve files on optical media.