While it is certainly true that CDs and DVDs look a great deal alike, there are a few significant differences that make each electronic device more appropriate for various functions. Here are a few examples of how the two data options are quite different from one another.
One of the first differences between CDs and DVDs to note is in the amount of data storage that is possible with each device. The typical DVD will provide in the range of seven times the capacity that is available on a compact disk. DVDs make use of a series of recording layers and also store data on both sides of the device, which makes a big difference in the storage capacity. The older technology associated with the CD does not allow for these same applications.
The equipment used to read the data on these two devices also is geared to accommodate the different configuration for each device. DVDs actually record data is smaller nonreflective holes, referred to as pits, that are located in the grooves of the surface. With compact discs, the laser that is used to scan the surface and retrieve the data is different in size and intensity that is required to read the DVD. This difference in the technology used to record and retrieve data makes it impossible for DVDs and CDs to be read on the same equipment.
A third difference has to do with the speed of the data retrieval from CDs and DVDs. The standard DVD will access stored data much more quickly than compact disks. Generally, the transfer rate for a CD is around 150KB per second. The typical DVD has a transfer rate that is roughly seven times greater.
One final important difference between CDs and DVDs is the type of data that can be stored. UDF or Universal Data Format technology underpins DVD recording capacity. That means the DVD can store data, video, audio, or any combination of the three. A CD, which does not comply with UDF standards, is not capable of the same storage ability.