CDs
CD also known as a compact disc, which is an optical disc, used for storing digital data. It is developed for storing the music at the start; it is permitted to store data of other kinds. CDs are the physical standard medium for commercial audio recordings. Usually the CD has the diameter of 120 mm and holds audio for about 80 minutes. The mini CD has several diameters varying from 60 to 80mm. They are used sometimes for device drivers or CD singles storing about 24 minutes of audio. In the industry, CD-Rs and CD-ROMs are the most widely used technologies.
