There are a variety options to peruse when working with optical discs. The most common include CD, DVD, and Blu-Ray discs, which are all replicated (manufactured) products. Before choosing which format is best for your needs, one should make sure they understand what makes each of these formats unique.
The compact disc is a digital optical disc data storage component. This format can be used in a variety of manners, such as sound recordings, data storage, video recording, etc. While there are differing data capacities, most standard compact discs can hold up to 80 minutes of uncompressed audio data.
Next, the DVD (digital optical disc storage) offers an increased storage capacity over standard compact discs, while maintaining the same dimensions. DVDs are most often used for digital video and digital audio storage.
Finally, the Blu-ray disc is a digital optical disc data storage component created to give more power to the standard DVD format. Blu-ray discs have the same dimensions as standard CDs and DVDs. However, these discs are read using a blue laser, rather than the standard red laser. This laser produces electromagnetic radiation, which the human eye observes as blue, hence the name. Blue-ray discs are perfect for information which needs to be stored at a greater density than is possible with the longer-wavelength red laser used for standard compact discs or DVDs.
By far, disc formats remain one of the most reliable, cost-effective ways to distribute information. Regardless of which format you choose, KopyRite can deliver on your optical disc needs.
A basic CD-ROM disc is 120mm in diameter and 1.2mm thick. It is formed from three layers: a back layer of clear polycarbonate plastic, a thin sheet of aluminum and a lacquer coating to protect the disc from scratches and dust. The most common format of CD-ROM holds approximately 800 megabytes of data which is approximately equal to 80 minutes of audio.During the replication process, melted polycarbonate is molded with millions of tiny indentations called pits that spiral from the center of the disc outwards. It is then coated, with a thin layer of aluminum, giving the disc its characteristic silver color. Unraveled and laid in a straight line the spiral of data would stretch four miles! Data is read from an optical disc by sensors that detect light reflected off the disc from a laser located in the drive. The laser will direct a light beam at the rotating disc. Some portions of the disc will directly reflect the light, while other portions will diffuse the light. The amount of light read by the sensor will fluctuate based on whether it is detecting the reflected light or the diffused light. It is these fluctuations in intensity that are converted into the digital signals that are sent to the computer from the drive. The areas that reflect the light are known as "lands" and the areas that diffuse or diffract the light are known as "pits". These pits and lands are created on the disc surface in several ways depending on how the disc is made. The two types of optical discs generally used are replicated discs and recordable discs. The concept of how they are read, however, is similar. A laser light is directed at the disc. When the light hits a land it is directed straight back towards a sensor. When the light hits a pit it is "scattered", thereby reducing the intensity of the light reaching the sensor.
Replicated CD's and Recorded CD's are manufactured differently and also vary in the way that the light is diffused. As a side note, it is frequently assumed that the "pits" and "lands" represent the binary numbers "1" and "0". This is not the case. It is actually the transition from a string of pits or lands that signals the change from a 1 to a 0, or vise-versa. This whole explanation is somewhat technical and for most people extremely irrelevant!