Question

how we can differentiate cd and dvd

Answer 1

The major difference is the capacity.

Compact Discs (CDs) can store only upto 700 MB while Digital Versatile Discs(DVDs) can store upto 4.7 GB.

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Answer 2

Before DVD, CD is all the rage on the media market. Unlike cassette and VHS tapes, CD can jump to a certain area directly without rewinding or forward the medium. Data store on a CD will not deteriorate even if it has been played many times. That's why it is much better than cassette and VHS tapes and gains more popularity. At that time, CD was the main media for software and computer programs. Later DVD came into being with a much higher capacity. DVD's high compatibility makes it popular for storing videos and programs. Movie makers can add some other materials to their DVD movies. But because of cost, CD is more widely used on music albums.

CD, short for Compact Disc, is an optical medium that can store digital data. It is designed to replace the old cassette tapes. Usually, a standard CD can store about 700MB of data. That means you can store CD quality audio that can last for about 80 minutes or video lasting about 60 minutes. DVD, short for Digital Versatile Disc, is also an optical medium to store digital data. A standard DVD can hold 4.7 GB of data. So DVD is widely used to store large files like video and movies. The capacity is the biggest difference between CD and DVD.