What is a CD?
A compact disc is a thin, circular disc of metal and plastic about 12cm (just over 4.5 inches) in diameter. It's
actually made of three layers. Most of a CD is made from a tough, brittle
plastic called polycarbonate. Sandwiched in the middle there is a thin layer
of aluminum. Finally, on top of
the aluminum, is a protective layer of plastic and lacquer. The first thing you notice about a CD is that it
is shiny on one side and dull on the other. The dull side usually has a label
on it telling you what's on the CD; the shiny side is the important part. It's
shiny so that a laser beam
can bounce off the disc and read the information stored on it.
What
is the full form of CD?
The
full form of CD is the compact disc. It is a flat, tiny-rounded storage unit
that can store information of up to 700 mb and 4.75 inches in diameter. It is
compact, so it is possible to carry wherever. Because its consistency does not
degrade with time & long duration, we could operate it countless time. CDs
can store digital formats of any information, such as video, audio, text,
photographs, and so on. The data is stored on the disc in the form of tiny
notches, and when the disc is performed, the information is interpreted from an
optical drive by a laser.
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Who invented CDs?
The
technology behind CDs was invented in the late 1960s by James T. Russell
(1931–). An avid music fan, he longed for a sound-recording system that would
reproduce music more exactly than LP records and cassette tapes. He patented
the first ever optical sound recording system in 1970, refining it over the
years that followed. Audio CDs finally made their commercial debut in Europe in
1982, launched by the Sony and Philips electronics corporations,
A CD was later allowed to store collections of information on its disc as technology advanced. The compact disc then named as CD-ROM(Compact Disk-Read Only Memory).
The
information stored only has the read operation but not the writing process. The
very first CD audio player was made available to the public in Japan by Sony
company.
Characteristics
of CD
A
CD’s characteristics involve:
- A regular Compact Disc has a diameter of around 120 millimeters (mm) and a width of 1.2 millimeters (mm).
- It consists entirely of plastic and has a shiny, glossy appearance.
- It just weighs up to 15 or 20 gram.
- A CD’s storage space is up to 700 MiB, that ensures that a Compact Disc can operate up to 80 minutes of sound quality.
- Types of compact discs
- The Compact Disc-Read Only Memory (CD-ROM) is a common and standard optical disc used during computer data processing.
- Recordable Compact Disc (CD-R) has a write process option. It is made of quality dye that, as light strikes on it, reflects various colors. The CD-R has a life span of 20 to 100 years.
- The Rewritable Compact Disc (RW-CD) is a disc where material can be removed and rewritten over and over again.
- The Video Compact Disc(VCD) helps you to see a moving picture on the screen easily.
Benefits
of CD
- In terms of size, it is tiny.
- It is a portable device.
- Access to Data Faster.
- It is inexpensive to manufacture.
Limitation
of CD
- It has a smaller storage capacity.
It
can create scratches when it is used quite frequently.
