The Optical Drive retrieves and stores data on optical disks, such as CDs, DVDs and Blu-ray discs. The optical Drive is also known as the CD drive, ODD, BD drive, and the DVD drive. An Optical Drive is similar to the size of a thick paperback book. There is a small Open and Close button located on the front of the Drive. The button ejects and retracts the drive bay door. This is where the CDs, DVDs and BDs are inserted and ejected from the Drive. Small drilled holes are located on the side of the Optical Drive allow for easy placed in the drive bay inside the computer case. The Optical drive is placed so that the end with the drive bay faces outside and the end with the connections faces the inside of the computer. The back of the Optical Drive contains a port for the cable that connects to the motherboard . The type of cable that is used varies, but the cable is usually included when purchasing the Optical Drive, along with a connection for power from the power supply. There are jumper settings on the back end of the Optical Drive that define how the motherboard recognizes the Drive when more than one is present. The Optical Drive works by way of a motor that spins the disc in the drive at a high speed, while a laser reads the data off of it. The drives require a lot of power because of all the movement resulting in the ability to hear it functioning.
http://pcsupport.about.com/od/componentprofiles/p/p_odd.htm
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The first laser disk was invented and demonstrated in 1972 . The video signal was stored in the video disk in a form similar to the video cassette recorder. This video disk was known as the 12-inch Laservision. Later, Sony and Philips designed the 5-inch audio CD in 1975. This became the standard for all CDs. The first 12-inch writeable disk was designed in 1977 and later in 1980, Sony and Philips defined a version of a CD used for storage of digital data for computer applications. This invention was called the CD-ROM.
http://www.lintech.org/comp-per/12OPDISK.pdf
