By reading the reflected light beams, a disc drive decodes the information on a disc. A scratch deflects the laser beam off track and information is never received by the laser reader. The smallest scratches can effect many lines of data. The most unprotected side of a disc is the top or graphic side. Where a scratch occurs determines if your disc is repairable.
Data resides on the top side of the plastic disc.
It is extremely important to protect this side of the disc. Manufacturers, however, leave this side highly exposed. A scratch on the top, through the foil or stamped data, will result in lost data and a non repairable disc. A scratch that occurs on the bottom side of a disc, however, may be resurfaced and polished out. The depth of the scratch will determine the success of the repair.