ODM Optical Disk Memory is a recording medium formed by coating a thin layer on a substrate for recording. The difference is that the round sheet of the substrate is made of organic glass with low thermal conductivity and strong heat resistance. A protective sheet is then coated or deposited on the surface of the recording thin layer to protect the recording surface. There are two types of recording sheets: non-magnetic materials and magnetic materials. The former constitutes an optical disc medium, and the latter constitutes a magneto-optical disc medium.
Advantages: large storage capacity and easy replacement of platters
Disadvantages: storage speed is an order of magnitude lower than hard disk