What is the Difference Between CD and DVD Media?

Although both CD and DVD have the same media size and shape, the similarity ends there. There are numerous points monster models difference between the two, as listed below:

Data pits and lasers

A disc has microscopic grooves that move along in the Monkees spiral around the disc. Both CDs and DVDs have these grooves. Laser beams are applied to scan these grooves. As you may be aware, digital information is represented in ones and zeroes. In these discs, very tiny reflective bumps (called lands) and non-reflective holes (called pits), which are found alongside the grooves, reflect the ones and zeros of digital information.

Here lies the difference by reducing the wavelength of the laser (from the 780mm Kansas Lemon Laws light used in the CD) to 625mm or more infrared light, DVD technology has managed to write in smaller pits as compared to the standard CD. This allows for a greater amount of data Fistful of Dollars track. The minimum length of a pit in a single layer machine-information.infoDVD-RAM is 0.4 micron, as compared to 0.834 micron for a CD.

Also, the tracks of DVDs are narrower, allowing for more tracks per disc, which again translates into more capacity than a CD.

Layers

As explained above, DVDs have smaller pits and the lasers have to focus on them. This is done by using a thinner plastic substrate than in a CD, which means that the laser has to pass Batman a thinner layer, with less depth to reach the pits. It was this reduction in thickness which was responsible for discs that were only 0.6mm thick half that of a CD.

Data access speeds

DVDs access data at a much faster rate that do CDs. Here is a comparison a 32X CD-ROM drive reads data at 4M bytes per second while a 1X DVD drive reads at 1.38M bytes per second. Thats even faster than an 8x CD drive!

UDF (Universal Data Format)

Recording formats of CDs and DVDs are quite different. DVDs use UDF ( pda-devices.infoUniversal Data Format). This allows data, video, audio or a combination of all three, to be stored in a single file structure. The advantage of this is that any file can be accessed by any drive, machine or consumer video. CDs, however, are not compatible with this format.

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