cd's and dvd's

[spiderman]

how do they work

[wildwood]

A disc is a plastic platter with layer of various qualities of metallic emulsion inside it. When programmed (burned or written) the disc spins and irregularities are burned in the emulsion. When played the laser picks up these fluctuations of the surface and convert it into digital data. Your computer or CD/DVD player converts the data into sound.

A rewritable disc has more than one layer and when deleting these special layers are activated and straightened from the irregularities.

Dispite popular belief, it is not the bottom of a disc surface that contains the info, but the emulsion layer inside the plastic. It is however still important to keep the plastic bottom as pristine as possible to avoid any reflection for the laser beam.

[rojash]

A Cd contains tiny buckets of ones and noughts. When the disk spins, the centrifugal force hurls the ones and noughts off the surface where they are collected by a tiny suction tube which directs them to them to the AD chamber.

The rate and quantity at which they strike the walls of the AD chamber cause it to emit vibrations which are sent along voice pipes to your speaker system. The faster the CD spins, the harder they hit the walls, and so the louder they sound. As the ones and noughts are very tiny, there are billions of them in the buckets, but eventually, if played often enough, the disk will run out.

Philips (who invented the CD) had hoped to provide a network of filling stations where you could refill your empty CDs but the music industry wanted to charge such exorbitant royalties that the plan was dropped.

[Panic Button]

Vinyl records used to start at the outside and play towards the middle. Cds start in the middle and work towards the outside.

[deadskerry]

I wrote a long and detailed answer then when i submitted got an error message gah. all i will repost is don't take rojash seriouslty!