The Invention of Compact Discs
The Invention of Compact Discs
Did you know that until the late 1800s the ability to record audio (voice or music) was just a dream? In 1877 "Mary Had a Little Lamb" was recorded and played on Thomas Edison's first experimental talking machine called a phonograph. About one hundred years (1982) after Edison's introduction of the phonograph, two companies, Sony and Philips, marketed the first digital audio 5-inch compact disc (CD). A CD-ROM (Compact Disc Read-Only Memory) disc is basically the same as a CD audio disc, except for the way the data is stored on the disc. A CD-ROM allows multimedia data (audio, text, computer graphics, and video images) to be stored on the same disc for use in a personal computer. For example, a CD-ROM can contain the complete text of the dictionary, 24 volumes of an encyclopedia, a thesaurus, a world almanac, an atlas of the world (including illustrations and animation), and a talking reference library with word pronunciations, quotes, and music. CD-R (CD-Recordable), also called CD-Write Once (CD-WO), allows the user to record using a disc and a desktop computer. The success of compact discs can be attributed to their durability, affordability, and compatibility.
Compact discs are more durable than prerecorded, long-playing phonograph records (LPs) and cassette tapes. A compact disc is a laser-encoded disc that is made from the same material as bulletproof glass (polycarbonate plastic). It is almost indestructible. Unlike a record player, where a needle actually touches the record to play the music, a CD player or CDROM drive focuses a laser light on the reflective surface of the disc. Nothing but the laser beam touches the disc; therefore, discs do not wear out. It is estimated that a compact disc will last about 100 years.
Read-only memory (ROM) means that the computer data is permanent and un-modifiable. Files cannot be accidentally deleted from CDROM discs. Because the data on a CD-ROM cannot be modified, a virus cannot invade the discs.
All types of compact discs can be mass-produced in large factories through a process called injection molding, making them cheap to produce. Since an audio compact disc was cheap to produce and much easier to carry and more durable than an LP record, its popularity increased. As a result of this increase in market demand for audio compact discs, Sony introduced its portable audio CD player in 1984. Now you could listen to your CD anywhere.
The Microsoft CD-ROM conference held in 1986 (which became known as the "Woodstock of CD-ROM") was considered the traditional starting point for CD-ROM technology. It was during this conference that Bill Gates (1955- ) predicted that the CD-ROM would become the cheapest way to distribute large amounts of machine-readable financial data. Gates's prediction came true. Financial institutions in the 1990s have discovered that the cheapest way to distribute large amounts of machine-readable data is with a CD-ROM. Because CD-ROMs are easy to manufacture and cheap to produce, they have become the fastest growing consumer electronic device in history.
In the early 1980s Sony and Philips worked together to create the compact disc for audio players. This venture between the two companies guaranteed that any audio CD would play in any audio CD player. Together they established a standard for the physical characteristics of a compact disc. Since the color of the binder in which this standard was published was red, it became known as the Red Book standard. This standard is the foundation on which all other compact discs' specifications are built. Sony and Philips also established the specifications for the physical characteristics for the CD-ROM. These computer discs would use the same laser technology as the audio CD. As CD-ROM discs were introduced into the personal computer market, their specifications were created based on the CD Red Book standard. It was called the Yellow Book standard. Initially, all CD-ROMs had the same physical properties, but the filing system used for storing the information contained on the discs was not standardized.
The following generations of compact discs were each based on the previous standard. The Compact Disc Interactive (CD-I) operating system and disc layout structure was defined in the Green Book standard. The Orange Book established the specifications for allowing the user to write audio and/or data to the disc for a Compact Disc-Magnetic Optical (CD-MO) and for Compact Disc Write Once (CD-WO). This technology allowed data to be written but not erased. Initially, however, these compact disc standards did not designate how the files should be stored on the disc. In November 1985 company representatives from Apple Computer, Digital Equipment Corporation (DEC), Hitachi, LaserData, Microsoft, 3M, Philips, Reference Technology Inc., Sony Corporation, TMS Inc., VideoTools, and XEBEC met at the High Sierra Casino and Hotel in Lake Tahoe, Nevada. This committee became known as the High Sierra Group. The purpose of the meeting was to propose a standard file format structure for CDROM discs so that any CD-ROM could be played in any CD-ROM player. The High Sierra standard (as it was sometimes called) was adopted in October 1987. This proposal was submitted to the International Standards Organization (ISO) for acceptance. In 1988 the ISO, which sets international standards through committees located around the world, established universal CD-ROM standards based on the High Sierra recommendation called the ISO 9660. It described the directory structures and file layout for storing computer files on a compact disc. This standard stated that any CD-ROM could be used in any personal computer CD-ROM drive regardless of the type of operating system used.
In the 1990s compact discs have become the standard for storing large quantities of information for a perfect reproduction (the recording sounds the same every time you play it, no matter how many times). An audio CD holds about 74 minutes of music or text. A CD-ROM holds approximately 260,000 pages of text, or over 1,500 floppy disks. (Note: The word disc refers to optical storage media, such as CD audio, CDROM, or video disc. The word disk refers to magnetic storage media, such as floppy or hard disks.) Floppy disks did not have the storage capacity needed to store large amounts of computer data. A company (such as Microsoft) can produce and ship one CD-ROM that includes the software application, the online manual, and online tutorials with audio, cheaper than 36 floppy disks and printed manuals. Personal computers sold since 1995 contain a CD-ROM drive. As a result, computer software companies began producing and shipping their software on discs. The compact disc has become an optimal means of storing and delivering massive text and multimedia applications for the personal computer.
With the durability, affordability, and standardization of the compact disc industry, more industries and businesses began utilizing the compact disc. Even the United States government began using it for data distribution.
In 1983 over 800,000 audio compact discs were sold. For the first time in 1988, CD sales surpassed LP record sales. Although CD-ROM has become the primary data storage and distribution medium during the 1990s, the next generation in storage is the Digital Video Disc or Digital Versatile Disc, commonly referred to as DVD. The DVD standard was introduced in September 1997.
Initially the Digital Video Disc (DVD-Video) technology was developed to be played in a DVD player hooked up to a TV. The DVD improved movies by providing better video and audio quality. The computer industry developed the DVD-ROM, which allowed large amounts of computer data to be stored and accessed quickly. Because CD-ROM manufacturers are developing the DVD-ROM hardware, which also reads compact discs, CD-ROM drive production is expected to diminish in favor of DVD-ROM drives. The difference between the DVD-Video and DVD-ROM is similar to that between audio CD and CD-ROM. Because of the two different types of DVDs, the acronym now stands for Digital Versatile Disc.
Although the DVD physically resembles a compact disc, it can hold 7.5 times more data (audio, computer data, and video) than an audio CD. The DVD can store about 16 hours of music (audio CDs allow us to hear up to 74 minutes of music), up to 8 hours of video, or up to 17 gigabytes of data. At this time, the only DVD available is a read-only disc; however, there is a rewriteable version of DVD for computers currently being developed. The DVD is expected to replace the audio CD, videotape, laserdisc, CDROM, and perhaps the video game cartridge.
This new generation of optical disc storage was based on the compact disc technology. It could not have happened without the development of the compact disc. Although CDs are being replaced with DVDs, for about 15 years the compact disc was considered the best.
REBECCA J. TIMMONS
Parker, Dana and Starrett, Bob. New Riders' Guide to CD ROM. Second ed. Indianapolis, IN: New Riders Publishing, 1994.
Sherman, Chris, ed. The CD-ROM Handbook. Second ed. New York: McGraw-Hill, 1994.