Differences Between Compact disc Digital video disc Media

Although CD and DVD are the same size and shape of the media, things have in common ends. There are many things different between the two, as they have done and how much to take.

A disc has microscopic grooves that moves along a spiral around the disc. CDs and DVDs both have these grooves, with laser applied to gold exploration in these grooves too.

As you may know, digital information is represented in the existing zeros. Within these courses, a very small bumps and other countries known reflection reflective holes known as pits, which is located next to the grooves, reflect both of them and zeros of digital information.
By reducing the wavelength of the laser of 625 mm or more infrared light, DVD technology has managed to write in small gaps compared to the standard technology of CD. This will allow a greater amount of data per track on the DVD. The minimum length allowed for a pit in a single layer DVD-R is 0.4 microns, which is considerably higher than the 0.0834 micron that a CD offers.

The tracks of a DVD are narrower and, thus more tracks per disc, which also results in greater capacity of a CD. The avaerage single layer DVD holds 4.5 GB of data, while a CD is a mere 700 MB.

As indicated above, a DVD has smaller pits and the lasers need to focus on them. This is actually achieved by using a plastic substrate thinner than a CD, which means that the laser must pass through a thinner layer, with less depth to reach the well. It is this reduction in thickness, which is responsible for discs that were only 0.6 mm thick - which is half of a CD.

DVDs will access data at a rate much faster than a CD. The average 32X CD-ROM drive reads data at 4MB per second while a 1X DVD drive reads at 1.38Mb second. This is even faster than an 8X CD drive.

CD and DVD recording formats are very different, as DVDs use UDF, or Universal Data Format. This format allows data, video, audio, or a combination thereof may be stored in a single file structure. The advantage is any type of file can be used in any computer drive, or even consumer video.
Second, the CD is not compatible with this format.


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