Laser

The fact that a laser beam can be focused down to a very small spot has been used by the information industry and implemented in the form of the compact disc. The area needed to store a bit of information on a disc surface is smaller when optical reading is used than when magnetic reading is used. Much more information can be stored on a compact disc (several gigabytes) than on an equivalent magnetic disc (several hundred megabytes). This represents a savings in space and cost, which has opened up new markets for optical data storage-music CDS, CD-ROM, and optical storage libraries for large computer systems.