The Difference Between CDs and DVDs

23 Jul

Posted by author as technology

>>> How to Repair Scratched CDs and DVDs

The Differences Between CDs and DVDs Are Microscopic

CDs and DVDs are two completely separate and distinct pieces of technology but to the naked eye they look precisely the same. There are many different things between the two, such as what they hold and how much they can hold.

The reason for the big difference in the amount of data storage will become apparent when you understand how data is written to or burned to CDs and DVDs. A laser is used to burn pits around a spiral groove in the disc. A laser is an intensely focused beam of light and all lasers have a particular wave length. A smaller wave length will produce a smaller pit. A smaller pit obviously takes up less space and ultimately resulting in the ability to store more information in the same amount of surface area.

DVDs and CDs are digital storage mediums which basically means that all data is stored as ones and zeros. Pits and lands (no pits) burned onto the surface of the disc are what make up the ones and zeros. When the disc is read the laser moves around the discs surface and is reflected off the lands but not off the pits. Microprocessors in the disc drive take the information from the laser and convert it into a digital format that your computer can understand.

Because the spiral groove is narrower on a DVD than a CD it is subsequently longer and able to hold more data. The typical single layer DVD holds 4.5 GB of information, while a CD holds a mere 700 MB..

As the pits on a DVD are smaller the physical make up of a DVD has to be different to a CD in order to allow the laser to focus on them. The DVD has a thinner plastic substrate than a CD making it easier for the laser to pass through and get reflected back.

DVD technology also has a much faster rate of reading and processing data. A 52X CD-ROM can read data at 8.4Mb a second while a 24X speed DVD can read data at about 32MB a second. This is a massive speed increase.

DVDs are still the most popular choice for movies and data storage these days but are slowly being taken over by Blu-Ray. CDs will be available for a while yet but as Blu-Ray prices come down and storage needs continually spiral upwards I can’t see them lasting forever. For more information on CDs and DVDs in regards to packaging and marketing visit this website CD DVD Packaging.

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