CD-ROM (Compact Disc Read Only Memory) is an increasingly attractive format
for businesses and consumers alike, as both the installed base of CD-ROM
drives and the number of available CD-ROM titles are experiencing tremendous
growth. Not only is CD-ROM a great storage medium for multimedia, it's an
excellent data carrier for any application requiring large capacity and
high reliability. So, virtually any institution or business can take advantage
of CD-ROM technology.
| ||
Information |
Applications |
Industry |
|
|
|
CD-ROM originated from the audio compact disc, and thus its physical dimensions and characteristics are the same. The main difference between CD-ROM and CD Audio is that CD-Audio contains only audio data, while CD-ROM may contain audio, computer, and video/picture data. The molded plastic compact disc incorporates a continuous spiral of pits, which contain the data. An aluminum reflective layer allows a laser in the compact disc drive to read the encoded information. Data integrity is protected by a lacquer coating on one side and a plastic substrate on the other side. Compact disc information or music is encoded with efficient error detection and correction codes so that drives can correct errors if they occur.
A compact disc can contain over 650 megabytes of user data or over 74 minutes of audio on a disc with a diameter of only 4.75 inches. This capacity is equivalent to 200,000 pages of printed text. Consider that if a human hair were laid on a compact disc, its width would cover 50 rows of pits.
A big advantage of compact disc for information publishers is the efficiency with which the media is manufactured. Once the data pits are recorded by a laser onto a "master", from which a metal stamper is produced, plastic discs are duplicated in a matter of seconds by an injection molding process. Thousands of identical replicas can be produced quickly and efficiently from one stamper. Publishers and distributors benefit through lower costs and quick manufacturing turn-around.
All media and drives with the compact disc logo must meet international specifications. This worldwide standardization assures publishers and consumers that a properly manufactured compact disc will function in any CD-ROM drive or audio player, making media portability very easy.