Parallel Readout of Optical Disks

Optical memory disks have been developed in recent years as mass storage media for audio, video, and computer memory applications. Write-once systems are already widely used, and reprogrammable systems are now starting to become commercially available as well. In all the existing systems the information stored in the optical disk is recorded and readout serially by focusing a laser beam on a single pixel. With an optical memory however it is possible to illuminate the disk with an extended beam and readout (as well as record in principle) large amounts of data in parallel [1]. This distinction between serial and Parallel Readout Optical Disks (PROD) is schematically shown in Fig.1. If the potential of PRODs is realized in practice it can eliminate the bottleneck that currently exists between mass memory and the information processing portion of a computer and thus greatly impact the speed with which computers can execute memory intensive problems. There are three main issues that we will address in this paper: The suitability of commercially available disks for this applications including the experimental characterization of a prototype magnetooptic system from SONY, the limitations imposed on parallel access due to the optical system, and the types of problems and computer architectures that can make effective use of the PROD capability.