Difference between CD and DVD - Computer world





Friday, October 11, 2019

Difference between CD and DVD

Difference between CD and DVD
CDs and DVDs are versions of an optical disc that differ mainly in size and manufacturing method. Generally, a DVD can store more data than a CD, one of the reasons is that the CD has a polycarbonate substrate on only one side while the DVD has both sides present. CDs and DVDs operate on optical technology where data is exclusively retrieved using light. A laser beam is focused into a CD or DVD to read and write data stored in the disk as bits. In this post you will learn -
Definition of CD
CD (Compact Disc) was the first step towards the idea of ​​digital encoding of data. It uses a method of encoding in which a 14-bit code takes one byte and this encoding technique also helps in detecting the error. It was a suitable replacement for magnetic disks because it brought out a low-cost solution for storing significant amounts of data.

The first layer of CDS is constructed by polycarbonate plastic which stores the data in an indent pit. This layer also provides a clear glass base. A flat or non-irrigated area is known as a land. Thin aluminum material covers program discs. In the back section, the disk is stamped with a label. Pivots are arranged in a spiral track from the middle to the outside of the disk, although storing index information at the beginning of the disk reduces the risk of damage. The pits are arranged in a spiral track, out of the middle of the disk, although minimizing the risk of damage by storing index information at the beginning of the disc and the length and width of the pits are 0.8 - 3 and 0.5 μm, respectively.

Definition of DVD
The advent of DVD (Digital Versatile Disk) has provided an option for videotapes used in VCRs (video cassette recorders) and CD-ROMs, as DVDs can store 7 times larger amounts of data than CDs. It provides videos with excellent picture quality and random access. The way the material used to make CDs is also used to make material DVDs but both process and layers are different, it is used on both sides like two CDs together. Are sticking It applies various techniques for error correction, RS-PC and recording code EFM Plus. What causes DVDs to exceed CDs - dense packing of bits, use of short wavelength lasers and generation of two-sided discs (data can be drawn from both sides). A short wavelength laser is used to convert a short distance of about 0.74 μm between the spiral track and a minimum distance of 0.4 μm between the pits. Like CDs, DVDs also have variants such as DVD-R, DVD-RW. Significant differences between CD and DVD
A compact disk can store data up to 700 MB while a digital versatile disk can store a maximum of 17 GB of data.
As DVDs can acquire a larger size, it is more prevalent than a CD.
The metal layer used for recording is placed under the label on the CD. In contrast, in DVD it is located at the center of the metal layer disc.
A CD can have only one layer of pits and land, whereas in a DVD it is of two types.
A CD has a distance of 1.6 micrometers between the spiral track and 0.834 micrometers between the pits on the disk. On the other hand, the DVD has a spiral loop of 0.74 micrometers and the distance between the pits is 0.4 micrometers.
CIRC and EFMP codes are used to correct the error in the CD. Against this, special techniques are used for error correction in DVDs, including RS-PC and EFM Plus.
Difference between CD and DVD
There is no main difference between CDs and DVDs, just the difference between the two is found based on their capacity.
Difference between CD and DVD:

The CD uses only one layer. DVD 2 uses the same layer. Due to which the capacity of DVD is high.
DVDs have 6 times more memory capacity than CDs.
DVDs are used for movies and software. CDs are mostly used for music albums and commercial data.
The DVD Higher Density uses a laser-sorted web for recording and reading. CD is only single side, it uses data storage using only one layer.
Both CD and DVD can be played in a DVD player. There only CDs are played in CD player.
The conclusion
CDs and DVDs are a means of optical recording where CDs were produced as audio storage formats, while DVDs are used as universal storage formats. In later technology, DVDs can store about 7 times more data than CDs and its format efficiency is also 32% higher than CDs.

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