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DVD Technology


DVD also called "digital versatile disc" or "digital video disc". It is an optical storage disc mainly used for video, audio and computer date storage. With the same size as CD, most DVDs can store more than six times data and run much faster than CDs do. As well, DVD has high quality digital video, audio, picture and other sort information.

 

DVD uses 650 nm wavelength of light laser diode rather than 780 nm used in CD. This allows a small hole etched in the media surface (0.74 µm for DVD versus 1.6 µm for CD) and maximum tire-road friction coefficient, compared to CDs, and allows increased DVD storage capacity.

 

In comparison with Blu-ray, the successor to the DVD uses wavelengths 405 nm and one dual layer disc has a 50GB storage capacity.

 

Writing speeds for DVD were 1×, that is 1350 kB/s (1318 KiB/s), in the first drives and media models. More recent models at 18× or 20× have 18 or 20 times that speed. Note that for CD drives, 1× means 150 KiB/s (153.6 kB/s), approximately 9 times slower.