24-11-2012, 04:13 PM
Optical Disk Technology
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INTRODUCTION
Optical disk technology is all set to redefine the home video en tertainment sector. The technol ogy has made this sector quite popular with the introduction of the audio com pact disk CD followed by digital versa tile disk or digital videodisk DVD).
DVD is anew type of CD havinga storage capacity of 17 GB. It can deliver data at a rate higher than CD-ROM.
Utilising MPEG and Dolby compression technologies, DVD is capable of holding hours of high-quality audio-visual con tents. Replacing the old VCR technology, DVI) provides an ideal support for inter active multimedia applications that are presently based on the CD-ROM technol ogy. Both computer and movie industries have jointly carried out research on DVD, making it the next digital movie medium.
More recently, digital versatile disks have ushered in a new era of high-quality mu timedia computing and video viewing.
Evolution
Existing secondary storage devices use magnetic drums, magnetic tapes, mag netic disks, floppy disks, and compact disks. All of these are inconvenient to use. To read a particular record on the mag netic tape, the entire file has to be scanned. This results in increased access time. Also, it is not possible th add a new record in the middle. To reduce access time, magnetic disks use disks coated with magnetic material. A read/write head moves across the surface, while the disk is constantly rotating at high speed. Floppy disk has to be stored and handled carefully. Also it has less storage space.
CD emerged as a powerful storage medium with the advent of applications that were too big to fit into a reasonable number of floppy disks. But graphic- intensive games, with built-in sound, oc cupy too much memory space to fit into a reasonable number of CDs. Here begins the story of DVDs stepping in with their higher capacity.
The high-density DVD is a new me dium with a different concept of enter tainment and data storage. Large stor age capacities of DVD broaden its multi media possibilities. DVD is sure to change the concept of multimedia and deliver the atre-quality video and surround sound to the desktop.