Nero writes additional information in last few sectors of CD-ROM?

Hi,

I am very new to CD file structure. I have one utility using which we can parse the sectors of a CD-ROM. I am following the ISO9660 standard. I am able to understand all the information about volume descriptors, path tables and directory descriptors. But in the last few sectors of CD-ROM there is some information that I could not understand. I read 2 CD-ROMs, which are burnt by Nero burning software, sector-by-sector, both are having some information after the data space in the last few sectors of the CD-ROM, related to all files, in the last few sectors, which is not specified by ISO 9660 standard.

I checked other CDs which are burnt with software other than Nero. They are not having the information after the data space. Please help.