With the explosion of CD Audio and CD-ROM discs today, most people are aware of optical disks and very likely use some form of optical disk technology, whether it be a home CD Audio player or a 2 Terabyte optical disk jukebox. Optical disks are currently making a significant impact on how we store, manage, retrieve, and distribute information.

This is particularly important for the geophysical industry. This industry relies on the collection, processing, distribution, and archival of vast amounts of geophysical and geological information. Past and current limitations with various computer technologies, including storage and retrieval devices, have and continue to directly affect the industry. Optical disks are ever increasingly being used by the industry to overcome many of these limitations and may potentially change the management of information throughout the industry.

The purpose of this paper is to present an overview of optical disk technology, with particular attention to several different types of digital optical disks: WORM, Erasable, CD-ROM, and CD-R. The information in this paper will hopefully assist both individuals and organizations with the selection and usage of optical disks.

2.1 What is an Optical Disk?

Simply stated, an optical disk is a plastic, glass, or metal disk ranging in size from 1.8" to 14". Information is stored on the disk by means of micro-sized pits that are written and read using a laser beam.

2.2 How Do Optical Recorders and Players Work?

They use a highly sophisticated but relatively inexpensive tracking system to lock a laser beam onto one of tens of thousands of circular tracks on the disk to record or read information on that track. The pattern of bits contains the information for that track, which may represent pictures, sound, video, numerical data, or any other form of information. In simple terms: One digital bit per pit!