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What is CD?
CD is a polycarbonate circle 1.2 mm thick and a 120 mm diameter, covered with the very thin metal layer (gold, silver, aluminum, etc.), and a protective layer of lacquer a label representing the content of the disc. On the outer surface the CD disk has a circular protrusion of 0.2 mm height, which allows it to lie not touching the surface. In the center of the disc there is a hole 15 mm in diameter.
Legends about CD
- There is a legend that the CD was not created by Philips and by Sony, but by the American physicist James Russell, who worked in the company of Optical Recording. Allegedly, he demonstrated his invention to store data in 1971. He made it for “personal” goals, wanting to prevent scratching vinyl records by needles. After 8 years such a device was “independently” invented by Philips and Sony.
- Vice-president of Sony Corporation Norio Ohga, who loved classical music, considered that the CD should be able to accommodate the 9th symphony of Beethoven (the most popular music in Japan in 1979, according to the survey!). Further investigation showed that the 9th Symphony by the Berlin Philharmonic Orchestra under the direction of Herbert von Karajan had a duration of 66 minutes. And the longest performance was by the Symphony under the direction of Wilhelm Furtwängler – 74 minutes. This was the decisive argument in deciding on the initial capacity of the disk – 650 Mbytes of information (or 74 minutes of recording).
- The disc diameter of 12 cm was chosen because it corresponds to the standard size of the substrate under the Dutch beer in pubs.
The takeoff of CD’s popularity was determined by the fact that they were used to record not only music but also any data. All every PC became equipped with a CD-ROM. The CD had a resounding success: in 2007 about 200 billion CDs (in every person on Earth, including infants and the elderly – not less than 30 discs!) were sold in the world. But technology does not stand still! With increasing volumes of information, newer media formats, such as DVD, USB Flash Drive, Blu-ray have appeared. In addition, Internet access allows you to quickly . large amounts of information. Gartner analysts believe that the CD has lost its commercial attractiveness. But we still can find them on the market! Why? Because many favourite artists use CDs to sell albums, many favourite movies are on CDs, a lot of useful software is recorded on CD. If there is no need to use DVD format, any information can be stored on a CD carrier – it’s cheaper and convinient for both manufacturers and users. And you can purchase CDs with any content you wish on Jiji! Moreover, here you can find the disks with your favourite songs, official versions of software and other interesting information!