WHAT IS THE DIFFERENCE BETWEEN DVD & CD.......?

DVD technology writes in smaller "pits" to the recordable media than CD technology. Smaller pits mean that the drive's laser must produce a smaller spot. DVD technology achieves this by reducing the laser's wavelength from the 780nm infrared light used in standard CD drives to 625nm to 650nm red light. Smaller data pits allow more pits per data track. The minimum pit length of a single layer DVD-RAM is 0.4 micron as compared to 0.834 micron for a CD. Additionally, DVD tracks are closer together, allowing more tracks per disc. Track pitch-the distance from the center of one part of the spiral information or "track" to the adjacent part of the track-is smaller. On a 3.95GB DVD-R, track pitch is 0.8 microns; CD track pitch is 1.6 microns. On 4.7GB DVD-R media, an even smaller track pitch of 0.74 microns helps boost storage capacity. These narrow tracks require special lasers for reading and writing — which can't read CD-ROMs, CD-Rs, CD-RWs, or audio CDs. DVD-ROM drive makers solved the problem by putting two lasers in their drives: One for DVDs, the other for CDs.

DVD is when you play movies..CD is for music