Optical disc image

ISO 9660 image
Filename extensions
.iso, .udf
Internet media type
application/vnd.efi.iso[1]
Uniform Type Identifier (UTI)public.iso-image
Magic numberVolume descriptor: CD001 at 32769. NSR0 at 38913 or 32769 for UDF.[2]
Type of formatDisk image
StandardISO 9660, UDF

An optical disc image (or ISO image, from the ISO 9660 file system used with CD-ROM media) is a disk image that contains everything that would be written to an optical disc, disk sector by disc sector, including the optical disc file system.[3] ISO images contain the binary image of an optical media file system (usually ISO 9660 and its extensions or UDF), including the data in its files in binary format, copied exactly as they were stored on the disc. The data inside the ISO image will be structured according to the file system that was used on the optical disc from which it was created.

ISO images can be created from optical discs by disk imaging software, or from a collection of files by optical disc authoring software, or from a different disk image file by means of conversion. Software distributed on bootable discs is often available for download in ISO image format. And like any other ISO image, it may be written to an optical disc such as CD, DVD and Blu-Ray.

  1. ^ Siyuan, Fu (24 January 2017). "application/vnd.efi.iso". IANA. Retrieved 18 July 2023.
  2. ^ "File Signatures". www.garykessler.net. Archived from the original on 2020-07-03. Retrieved 2020-07-01.
  3. ^ Fisher, Tim (24 April 2018). "What Is an ISO File?". Lifewire. Archived from the original on 23 June 2018. Retrieved 23 June 2018.