Abstract

Optical data storage has a long history dating back to the 1960s but, with the compact disk initially, it became relevant to the consumer and industry. The success of the early laser disk indicated the possibility of data storage based on optical phenomena and materials as an alternative to magnetic storage. Optical storage offers reliable and removable storage media with excellent robustness and archival lifetime and very low cost. Today, optical disk technology covers a wide variety of applications ranging from content distribution to professional storage applications. One of the major application areas for optical storage disks is the secondary storage of computer data in personal computers (PCs) and computer networks. An optical storage system is a particularly attractive component of the data storage network because it provides fast data access times and fair storage capacities while serving as a link between different multimedia and computerized systems. Perhaps, the most enabling feature of optical storage is the removability of the storage medium that allows transportation and exchange of the stored information between desktop and laptop computers, audio, video players, and recorders. In contrast to the flying head of a hard disk drive, there are separations of a few millimeters between the recording surface and the optical “head,” although active servo systems enable dynamic recording and readout from a rotating disk. Consequently, the medium can be removed and replaced with relatively loose tolerances allowing an optical disk to be handled in different drives.