The Basics

•A life of bumps and grooves.

The Spiral

•Data stored on the disc in a counter-clockwise spiral.

•This gives it much more code for the space.

•Stretched out, the track would be 3.5 mi long.

The size

•The tracks of data on a standard CD are incredibly small at just 0.5 microns wide.

So, How Do We read This Thing?

The Reader

On the Inside

http://static.howstuffworks.com/flash/cd-read.swf

Keeping it together

•Must synchronize disc speed and laser motion to keep reading the right section.

Back To Binary

•Bumps translate into either 1 or 0 depending on if there is a bump registered or not.

•The 1’s and 0’s are translated into an analog input by decoding processes.

So, What’s Different About DVD’s?•DVD’s hold 7 times the information held

on a CD.•How you ask?

The Dots

•The bumps and grooves on a DVD are much closer together than a CD.

•If stretched the track, it would be 7.5 mi long!

•A much narrower laser is then used to read finer bumps.

Even More Space!

•To fully realize the space able to be used on a DVD a disc can have two layers on each side, that’s 17 GB of storage space.

How Do you Read Two Layers?

•One laser reading two layers

HD-DVD? Blu-Ray?

•The only difference between DVD’s, HD DVD’s, and Blu-Ray discs is that instead of a red laser, they use:

A Sharper Light

The Future?

•Because Blu-Ray players are connected to the Internet, they can be easily updated.

•The new Blu-Ray 2.0 discs now have full internet support, and can sport Picture in Picture commentary.

Thank You

•Questions Anyone?