what is the difference between cd & dvd ?
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Answer / jyoti
cd stores 700 MB of data.DVD stroes 3-4 Gb of data. now new
DVD can store 40 GB of DVD
| Is This Answer Correct ? | 129 Yes | 43 No |
Answer / b naresh kumar
cd means compaq disk where as dvd means digital volatile
disk.
cd has 700 MB of memory where as dvd has 4.7 GB of memory.
| Is This Answer Correct ? | 112 Yes | 36 No |
Answer / jhakkas
cd::
1) cd allows only half part of cinema.
2) cd thiner than dvd
3) cd less price then dvd.(lowest Rs-7)
4) cd means compaq disk.
5) cd has 700 MB of memory.
dvd::
1) dvd allows four cinema.
2) dvd thiker than cd.
3) dvd high price.(Rs-17)
4) dvd means digital volatile disk.
5) dvd has 4.7 GB of memory.
| Is This Answer Correct ? | 117 Yes | 47 No |
Answer / aman
A cd can be played by a dvd player but a dvd cant be played by a cd player..
| Is This Answer Correct ? | 82 Yes | 20 No |
Answer / srk
The wavelength of the laser is reduced(from the 780mm
infrared light used in the CD) to 625mm cos of which DVD
technology has managed to write in smaller ‘pits’ as
compared to the standard CD. This allows for a greater
amount of data per track.The tracks of DVDs are narrower
which allows more tracks per disc this again translates into
more capacity than a CD.
| Is This Answer Correct ? | 63 Yes | 12 No |
Answer / deepak
Although both CD and DVD have the same media size and
shape, the similarity ends there. There are numerous points
of difference between the two, as listed below:
Data pits and lasers
A disc has microscopic grooves that move along in a 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 infrared 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 per track. The
minimum length of a pit in a single layer DVD-RAM
[http://computer-information.info] 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 through 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. That’s even faster than an 8x CD drive!
UDF (Universal Data Format)
Recording formats of CDs and DVDs are quite different. DVDs
use UDF (Universal Data Format [http://pda-devices.info]).
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, computer or consumer video. CDs, however, are not
compatible with this format.
| Is This Answer Correct ? | 46 Yes | 5 No |
Answer / arvind kumar
SPEG CD DVD
Diameter 12cm 12cm
Thickness 1.2mm 1.2mm
Numerical Aperture 0.60 0.38 to 0.45
traise pitch 1.6mm 0.75Um
capasity 700mb 4.7gb
ratation speed 200-500 rpm 570-1600 rpm
modulation 8/14 8/16
user data rate 1.41mbps 11.08mbps
| Is This Answer Correct ? | 29 Yes | 5 No |
Answer / anbu
cd has only one layer but for dvd has two layers
| Is This Answer Correct ? | 53 Yes | 32 No |
Answer / abnish kumar rajput
On the basis of Storage capacity cd only stores 700 MB
whereas a dvd stores 3-4GB.And cost is different with both
of them.Now a days dvd increases its storage capacity.
| Is This Answer Correct ? | 27 Yes | 7 No |
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