3. The Basics A life of bumps and grooves.

4. 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.

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

6. So, How Do We read This Thing?

7. The Reader

8. On the Inside http://static.howstuffworks.com/flash/cd-read.swf

9. Keeping it together Must synchronize disc speed and laser motion to keep reading the right section.

10. 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.

11. So, What’s Different About DVD’s? DVD’s hold 7 times the information held on a CD. How you ask?

12. 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.

13. 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.

14. How Do you Read Two Layers? One laser reading two layers

15. 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:

16. A Sharper Light

17. 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.

18. Thank You Questions Anyone?