ISO 9660, also referred to as CDFS (Compact Disc File System) by some hardware and software providers, is a file system standard published by the International Organization for Standardization (ISO) for optical disc media. It aims at supporting different computer operating systems such as Windows, classic Mac OS, and Unix-like systems, so that data may be exchanged.
ISO 9660 traces its roots to the High Sierra file system. High Sierra arranged file information in a dense, sequential layout to minimize nonsequential access by using a hierarchical (eight levels of directories deep) tree file system arrangement, similar to UNIX and FAT.
To facilitate cross platform compatibility, it defined a minimal set of common file attributes (directory or ordinary file and time of recording) and name attributes (name, extension, and version), and used a separate system use area where future optional extensions for each file may be specified.
High Sierra was adopted in December 1986 (with changes) as an international standard by Ecma International as ECMA-119 and submitted for the fast tracking to the International Organization for Standardization, where it was eventually accepted as ISO 9660:1988. The ISO 9660 file system format is now used throughout the industry.