Low cost and reliability, optical storage media, in particular the CD-R, has become the main steam data storage media. This presentation is intended to discuss issues related to the CD-rewriteable technology and the longevity of the data stored.

The working principle of CDs can be subdivided into three major categories, the CD-ROM, CD-R and CD-RW. The CD-ROM is primary used for music and software distribution and is manufactured by injection molding process. in contrast, CD-R and CD-RW are storage media allows data storage by users. The manufacture process involves spin-coating a layer of photo-sensitive organic dye on a polycarbonate substrate, then over-coated with a refractive coating. Writing of the data bits was achieved by photo-bleaching processes, which change the absorption properties of the dye. Considering the operation principle, there are many factors influence the reliability and storage life of the CD-R.