recovery cd data

CDs and DVDs that can be rewritten are based on a reversible optical phase change technology They use a material that becomes transparent or opaque depending on the heating temperature caused by the laser pulse. 

CDs and rewritable DVDs also have a table of contents, comparable to a file allocation table, which allows you to recover deleted files. 

On the other hand, it is impossible to recover lost data on a conventional for the simple reason the technology used based on hollows and bumps literally carved on the surface of the disc does not allow to erase the files.