Directions in Optical Storage

Article excerpt

Many benefits will accrue from the advances being made in mass storage technology, particularly in the optical arena. The high capacity and low cost per unit of data stored make optical media an effective storage solution. Accountants need to be aware of the implications of this technolog on the accounting profession as well as on the delivery of services.

Ever-increasing volumes of data must be stored and retrieved. Once measured by the number of punched cards in a file, today's data are sometimes measured in trillions of bytes. Rapid storage, retrieval and access to large volumes of information have become central concerns to management, users and information systems managers in all sizes of firms.


Data storage media have evolved from punched cards, punched paper tapes, magnetic drums, magnetic tapes and disks to today's technology--optical storage. Adoption of this technology is expected to increase dramatically as standards are resolved, new applications are developed and the price/performance ratio of the media continues to improve.

An optical disk provides greater storage capacities than do magnetic tapes or disks. Optical disks are available in 5 1/4-, 12-, and 14-inch formats. Storage capacities range from 115 million bytes or megabytes (megs) to over 700 megs of digital data per side. Optical disks such as write once, read many (WORM) drives and erasable optical disks are portable and could somebday displace magnetic tape due to their greater storage capacities, smaller space requirements, removability, transportability and longer guaranteed media life.

Examples of some of the more commonly used optical technologies follow.

* CD-ROM (compact disk--read only memory). CD-ROM is the medium of the publishing industry for the recording of reference data on disks. Data once written to disk by the publisher cannot be erased or overwritten but can be read many times. CD-ROMs currently have a storage capacity of up to 650 megs. Their read-only characteristic provides security for publishers of distributed information. CD-ROMs often are used in the distribution of reference data that changes infrequently. Growing numbers of catalogs, specialized databases, digitized data and software programs are being delivered on CD-ROM as personal computer users realize the advantages of having megs of data that can be accessed randomly and loaded into the computer within seconds. According to Dataquest Inc. (San Jose, California), more than 1,300,000 CD-ROMs will be delivered during 1991.

* WORM disks. WORM drives offer more flexibility than the CD-ROM devices because users are capable of writing data while online to the computer. In addition to keyboard input, information from video scanners, optical character recognition equipment and other devices also can be recorded on disk.

Data on WORM disks cannot be erased, making them ideal for a variety of applications requiring audit trails, such as in CAD/CAM (computer-aided design--computer-aided manufacturing), program development and financial and business applications.

WORM disks have the potential for replacing other methods of mass storage such as microfiche, microfilm and tape. WORM technology takes an image of documents and allows for random access retrieval of data. WORM drives are gaining popularity among data-intensive applications such as graphics and imaging systems. For these applications storage capacity, permanence of data and media removability are important considerations.

* Erasable optical disks. Some view this relative newcomer in optical storage as the ultimate in mass storage technology since erasable optical disks combine the storage capacities of optical technology with the reusability of magnetic storage. High-volume data users increasingly will find erasable optical disks an acceptable alternative to large magnetic storage devices. …