El Torito
From Just Solve the File Format Problem
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.