CD-R, CD-ROM, and DVD

Early Development

In the mid-1970s, several corporations began recording video on 12-inch discs read by lasers; the LaserVision format developed by MCA and Philips eventually became the standard. LaserVision players are still around, but were never popular; at their peak, only 1 percent of the U.S. population used them. VHS proved to be a much more popular format for video, despite its inferior quality, because it could record as well as play back.

In contrast to its early failure as a video-recording format, optical disc technology was immediately successful for audio recordings. In 1980, Sony and Philips co-endorsed a standard, called CD-DA (Compact Disc Digital Audio), for audio recording on optical discs. This standard was published in a book with a red binding, which is why today the CD-DA format is often called Red Book audio. In 1982, Sony and Philips introduced the world to the compact disc: a 120 mm diameter, light but rugged, plastic marvel of engineering that could hold 74 minutes of music. The new recording medium wasn't as susceptible to wearing out as vinyl records and magnetic tape, had a much clearer sound thanks to its higher signal-to-noise ratio, and was inexpensive to mass-produce. Even though the players initially cost around $1,000, hundreds of thousands were bought in the first year, and by the end of 1984 more than one million had sold around the world.

It didn't take long for engineers to realize that if compact discs could hold audio data, they could also hold other types of data, including computer programs. However, before CDs could be used for software, the engineers had to design much greater error-correction capabilities into them. After all, missing one bit of data from a song wouldn't be critical, but missing a single number from a computer program could cause it to crash.

Development of Multiple Formats

In 1985, the Yellow Book format, more commonly called CD-ROM (compact disc read-only memory), was introduced. CD-ROMs could hold computer software in a read-only form, which meant that once the software was written on the CD, it could not be altered. Since the drives initially cost $1,000, and their performance was somewhat poor due to the slow speed at which they transferred data, it took some time for them to be widely accepted. But as the cost of drives decreased and their performance improved, CDROMs became extremely popular. Thanks to their storage capacity (up to 700 megabytes), one CD-ROM could contain even large software programs, such as word processors.

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