El Torito

File Format
Name	El Torito
Ontology	Electronic File Formats Filesystem El Torito
Released	1995

El Torito is an extension of ISO 9660 format that specifies a standard way to make "bootable" CD-ROMs and DVDs. It was developed by IBM, and Phoenix Technologies.

Identification

One of the ISO 9660 volume descriptors begins with the byte sequence 0x00 "CD001" 0x01 "EL TORITO SPECIFICATION".

For the usual ISO 9660 file format, the sequence will appear at offset 32768+2048×k, for some smallish value of k≥0.

Specifications

• “El Torito” Bootable CD-ROM Format Specification Version 1.0
  • another copy, from archive.org

Sample files

• Ms-Dos Version 7.1 cd image → dos71cd.iso
• Puppy Linux Archpup → archpup-1204.iso, ...

Links

• Wikipedia: El Torito (CD-ROM standard)
• El-Torito OSDev Wiki article