What Is an ISO Disc Image?

ISO is a widely used disc-image representation for optical media, particularly data CDs and DVDs using compatible filesystems.

ISO 9660 and UDF

The Library of Congress describes ISO disk images as archives containing content from or destined for optical discs and notes their association with ISO 9660 and later UDF usage.

Data disc imaging

ISO is particularly useful for preserving data-disc filesystems and directory structures.

ISO limitations

However, not every optical disc should be reduced to ISO automatically. Audio CDs and specialist structures may require a different representation.

Verification

Document the source disc, image creation process, image size and checksum.

Preservation

Where extracted files are supplied, keep them traceable to the corresponding image or source disc.

Reference guidance: This article is informed by optical-media preservation guidance from the U.S. National Archives and the Library of Congress Recommended Formats Statement. Where appropriate, the article distinguishes preservation guidance from practical extraction procedures.