Preface

Since the beginning of history, man searched for means of storing information, in order to inherit knowledge to following generations.

At first the cave-man marked the hunting drawings on the cave walls.

Then came shard boards, parchment scrolls, paper, printing, and now the magnetic recordings.

Magnetic recordings is used on many devices such as: Tape recorders, computer tapes for storing information in big computers,  computer diskettes, and hard drives  for storing information in personal computers (pcs).

As society developed more, the amount of information is growing at an exponential rate. People are trying to find better ways to store information, and the current trend is toward:
Digital Optical Storage of Information.