What Is The Fundamental Difference Between CDs and DVDs
CDs and DVDs are two completely separate and distinct pieces of technology but to the naked eye they look identical. 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 burn 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.
Digital data is data that is stored as a series of ones and zeros. DVDs and CDs are digital data storage mediums so everything, including audio and video, is stored as ones and zeros. Pits and lands (an area where there are no pits) 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. The information from the laser is converted by way of a microprocessor into digital data that a computer can understand.
The spiral groove on a DVD is also narrower than a CD. This equates to a longer track and subsequently more data storage capacity. The average DVD can hold 4.5GB of data that is 6 times greater than a CD at around 700MB.
A DVD has smaller pits and the lasers need to focus on them so the physical make up of a CD is slightly different to a DVD. A thinner plastic substrate is used, giving the laser less material and less depth to get through to the surface.
DVD technology also has a much faster rate of reading and processing data. The difference in speed is very large with a 52X CD drive reading data at 8Mb a second and a DVD 24X drive reading data at 32MB second.
With Blu-Ray being the new kid on the block and because it has such a massive storage ability DVDs will slowly be phased out as will CDs. CDs are still very common and very cheap to purchase but I imagine they will slowly be phased out due to the increasing need for larger and larger amounts of storage space. For more related information on CDs and DVDs in regards to packaging and promotion go and visit this website CD DVD Packaging.