Facts around the discs. Did you know this?

The prototype of the modern Compact Disc /CD/ was a glass disc. It was developed in 1970 by the Dutch physicists Klaas Compaan and his colleague Piet Kramer.

Only eight years after the first prototype Philips made the decision to present a world audio disc standard. The material, used for the disc is Polycarbonate, developed by Philips subsidiary Poligram.

The disc diameter was set by 115 mm - it was enough for one hour music. Sony insisted for accommodation of extra data. Therefore the disc diameter was increased to 120 mm. According to one version of history, the reason for that was, that Sony wanted to fit in a single disc the Beethoven's Ninth Symphony conducted by Herbert von Karajan. The disc's diameter was followed by  change in male fashion in Japan - the pockets of the men's shirts were enlarged so that the disc  could fit in.

The inner diameter was set by the Dutch.  Their smallest coin - the Dutch dime, whose diameter was only 15 mm, determined the size of the inner diameter.

The compactdisc was introduced in Europe and Japan in the fall  of  1982.

The compactdisc entered the market of the United States in the spring of 1983 and quickly displaced the audio cassettes and record labels.

През същата година на пазара се появява първият CD плеър.

In 1990 the CD was also used in the PC. As a data storage it has more than 451 times the capacity of a floppy disk.

In the 1990s, there was a need to increase the capacity of CDs. It came the time of the DVD. The DVD is originally intended for video, so the abbreviation is perceived as a Digital Video Disk. Very soon the disc is widely used and is now perceived as the Digital Versatile Disc.

The Blu-ray Disc is relatively new in the family of disc. It was first introduced in 2000 in Japan at the CEATEC exhibition. A 120 mm diameter drive has a capacity of 25 GB for single-layer and up to 50 GB for double-layer disc. In 2002 a 100 GB disc was produced in Taiwan. However, the BDXL specifications allowed a capacity of 128 GB. This is possible with a laser operating in the blue-violet spectrum at a wavelength of 405 nm.

HD DVD (High Definition Digital Versatile Disc or High Density Digital Versatile Disc) has a relativelly small life. HD DVD format was used by Toshiba and was considered to be the next generation of DVD. But in February 2008 Toshiba announced that they abandoned the format and stopped the production of HD DVD players. It was the end of  the "formats war" and put the Blu-ray format on the market.