A system for data storage in which digitally encoded information in the form of microscopic pits on a rotating disk is accessed by optical readout. The compact disk was originally developed as a music carrier providing high fidelity, random access, convenience, durability, and low cost. Its attributes made it suitable for storing diverse data such as video programs and computer software, and improvements allowed recordability and erasability. Greater storage capacity and more sophisticated integration of features is provided in the DVD optical disk format.