Show Notes - Episode 15
SERIES: Lab Rats
EPISODE #: 15
RELEASE DATE: February 20, 2006
TITLE: Optical Media Explained
RUN TIME: 15:25:23
HOSTS: Andy Walker and Sean Carruthers
PRODUCER: Matt Harris
EDITOR: Sean Carruthers
SOURCE: www.labrats.tv/episodes/ep15.html
NOTES:
- Call for Help Episode #85 (3 minutes ain't enough)
Andy's weekly plug of - Absolute Beginners Guide to Security, Spam, Spyware, & Viruses
- Typically, the laser will actually hit the disc from the bottom, as the label side is usually on the top.
- Techically, 0's and 1's are created by the Transitions between puts and lands, but you get the idea.
- A pit reflects light more dimly than a land, and a diode is used to measure the difference in reflectivity.
- Though the shape of the disc is the same, data CS's , Audio CD's, DVD's all have a different sata structure.
- Master "stampers" are made from a glass master with nickel coating, with the pits burned into an emulsion layer.
- Unlike old-school vinyl records, data on CD's and DVD's starts on the inside, and moves outwards.
CD-R = Compact Disc Recordable
- - Burnable Media uses a special layer of dye that changes properties when hit by the
"write" laser.
CD-RW = Compact Disc Re-Writeable
- - about 100 re-writes per disic
- The alloy used for CD-RW is typically comprised of silver, indium, antimony and tellurium, or AglnSbTe.
- The burning process melts the alloy into an amporphous state. Erasing data anneals it back to cyrstalline.
The two most common sizes of CD
- - 650 MB (about 74 minutes)
- 700 MB (about 80 minutes)
- CD's use a 780 nanometer wavelengh.
- Beyond 700 MB, media may be unusable on older machines,as the space between data tracks becomes too tight.
Single-Layer DVD = Capacity of 4.7 GB
- - more than seven times the size of a CD.
- DVD uses a laser with a 650 nanometer wavelengh.
Dual-Layer DVD = Capacity of X.X GB
- - polycarbonate, dye and reflective layers brng the count up to 7 or 8 layers.
- With mulit-layer discs, one of the layers must be semi-transparnet so the laser can re-focus right through it.
- It's like the way a wire screen vanishes when your eyes refocus on an object on the other side of a screen door.
FUN FACT: on a second layer of a dual-layer DVD, the data goes from the outside to the inside, instead.
Next Generation DVD Media:
- - HD-DVD is more than three times the size of DVD for a single layer.
- Sony
- Apple
- Dell
- Hitachi
- Pioneer
- Panasonic
- HP
- LG
- Samsung
- Philips
- And More!
- Toshiba
- NEC
- Microsoft
- Intel
- Sanyo
- Fujitsu
- Canon
- Imation
- And More!
- Blu-Ray is more than five times the size.
- HD-DVD is 15 GB per layer, while Blu-Ray discs can cram up to 25 GB per layer.
- A dual-layer Blu-Ray DVD can fit 50 GB of data.
- Triple-layer HD-DVD can handle 45 GB.
- Triple-layer HD-DVD and dual-layer Blu-Ray are still in the development stage.
- So all these numbers could change.
- Blu-Ray supporters:
- HD-DVD supporters:
- This minimizes the "stutter" if the DVD player changes layers in the middle of a long motion picture.
- Both HD-DVD and Blu-Ray use a 405 nanometer blue laser to read data from the disc.
- Remember, we are trained professionals. Do not try this at home, unless you're bored.
- Refer to Episode 12 - HD-DVD and Blu-Ray for more information.
CREDITS
Lighting Provided by Geo Perdis
Lighting and Handheld Camera by Geo Perdis
Additional Cameras and Setup by Maurice Cacho
Theme Music by Dee Long
Title Graphics by Steve Huntriss (AKA ‘Tackie’)
Intern - Mike Britton
Cameras Courtsey of:
Special Thanks To:
Roger Chang
TechSmith
Geo Perdis
Maurice Cacho
Amanda
Eileen
Email Us At:
Show Notes by Michael Britton
(c) 2006 Labrats Media
