The following two interesting tools are referred there:
par2 - PAR 2.0 compatible file verification and repair tool
"par2 is a program for creating and using PAR2 files to detect damage in data files and repair them if necessary. It can be used with any kind of file."
dvdisaster - data loss/scratch/aging protection for CD/DVD media
"dvdisaster provides a margin of safety against data loss on CD and DVD media caused by scratches or aging media. It creates error correction data which is used to recover unreadable sectors if the disc becomes damaged at a later time."
Dvdisaster approach is specially interesting, as it can append its error correction information to an existing .iso file, using as much space as available to fill the smallest medium size (CD, DVD or DVD9). That information seems to be invisible, so it does not interfere with the media content.
dvdisaster -i cd.iso -mRS02 -c