The Differences Between CDs and DVDs Are Microscopic

CDs and DVDs are two completely seperate and distinct pieces of technology but to the naked eye they look precisely the same. The biggest difference that you will probably notice is that a DVD can hold far more data than a CD.



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. As the disc spins a laser is moved across the surface to burn pits in a spiral groove around the disc. A laser is an intensely focused beam of light and all lasers operate on a particular wave length. A smaller wave length will create a smaller pit. More pits in the same amount of surface area results in a larger amount of information and explains why a DVD is capable of holding so much more data than a CD.



DVDs and CDs are digital storage mediums which basically means that all data is stored as ones and zeros. The pits and lands (where there are no pits) on the DVDs and CDs represent 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. Optical technology reads the data and converts into the ones and zeros that your computer can then understand.



The tracks of a DVD are narrower as well, which allows for more tracks per disc and translates into more capacity than a CD. The most common DVD format can hold 4.5GB of data which is approximately six times more than a CD which only holds 700MB. Other DVD formats can hold much more given that they are double sided or dual layered.



Because a DVD has smaller pits and a laser needs to focus on them the physical make up of a DVD is different to a CD. A thinner plastic substrate must be used, giving the laser less material and less depth to get through to the surface.



DVDs will access data at a much faster rate than a CD can. The average 52X CD-ROM drive reads data at 8MB a second, while a 24X DVD drive reads at 32MB a second.



DVD's are currently the format of preference for most people these days but expect them to be taken over by Blu-Ray discs in the next few years. 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 additional information on CDs and DVDs in relation to presentation and promotion check out the following website Packaging CDs and DVDs.