An optical disc is an electronic data storage medium that can be written to and read using a low-powered laser beam. Optical disk can store much more data, i.e. upto 6 GB.
There are three basic types of optical disks namely, CD–ROM, WORM and Erasable.
CD-ROM: Like audio CDs, CD-ROMs come with data already encoded onto them. The data is permanent and can be read any number of times but CD-ROMs cannot be modified.
WORM: This term stands for “Write Once, Read Many” with a WORM disk drive. One can write data only once onto a WORM disk. After that, the disk behaves just like a CD-ROM.
Erasable: Optical disks that can be erased and loaded with new data are just like magnetic disks. These are often referred to as EO (Erasable Optical) disks
