Mirror CD is made of extremely thin aluminum or gold sound film and PVC plastic protective layer. Like floppy disks and hard disks, optical disks can store files and music information in the form of binary data (data pattern consisting of "0" and "1").

Data storage

To store data on the CD, it is necessary to convert the data into binary with the help of a computer, and then burn the data pattern on a flat reflective CD with a laser. The pits carved by the laser on the CD represent "1" and the blank represents "0".

sense data

When reading data from an optical disk, a directional beam (laser) moves rapidly on the surface of the optical disk. A computer or CD player reading data from a CD will observe every point where the laser passes to determine whether it reflects the laser. If it doesn't reflect laser light (there is a small pit there), then the computer knows that it stands for a "1". If the laser is reflected back, the computer will know that this point is a "0".

Music, files, programs

Then, these thousands or millions of "L" and "0" are restored to music, files or programs by computers or CD players.