Read only disc is an information medium. Comparing with the traditional visual audio medium, it has the characteristics of large capacity, portability and more intuition. It has come into wide use in the fields of Audio & Video, computer driver software, games, products instruction, promotion and so on.

The same as the read only disc, blank disc is also an information medium. The difference between them is just like the difference between white paper and newspaper. Blank CDs are applied in the information storage and small-range information transfer.

Blank discs also have different categories. According to their shape, it can be divided into three kinds as follows: