The CD drive shines a laser at the surface of the CD and can detect the reflective areas and the bumps by the amount of laser light they reflect. The drive converts the reflections into 1s and 0s to read digital data from the disc.
Contents
Does a CD read from the top or bottom?
all your excellent info. For all intents and purposes, them stating it is on top, is true. Yes, it reads the dye/data-layer from the bottom, but the laser reads up through the full thickness of the CD, and hits the dye layer, which is JUST under the aluminized later ON TOP.
What part of a CD gets read?
The dull side usually has a label on it telling you what’s on the CD; the shiny side is the important part. It’s shiny so that a laser beam can bounce off the disc and read the information stored on it.
How is information stored on CDs?
Data is stored on the disc as a series of microscopic indentations called “pits”, with the non-indented spaces between them called “lands”. A laser is shone onto the reflective surface of the disc to read the pattern of pits and lands.
Do CDs read from the outside in?
ll Compact discs and other optical disc players read from the inside of the CD out, just the opposite of a vinyl record.full CD holds a maximum of 74 minutes of music. When a disc isn’t full the outer portion of the CD appears blank.
What happens if you scratch the top of a CD?
If you scratch the top (label) side of a CD, you can fairly easily break through the laquer and metalisation – try it with an unwanted free CD from a magazine – you can then see through it 🙂 but data will be very likely lost (minor damage can be corrected by the error-correction system).
What are the parts of a CD?
CDs consist of three layers of materials:
- A base layer made of a polycarbonate plastic.
- A thin layer of aluminum coating over the polycarbonate plastic.
- A clear protective acrylic coating over the aluminum layer.
What does disc rot look like?
In the case of CDs, disc rot is the effect of oxidation of the reflective layer of the disc, resulting in what can look like bronze discoloration, or as one victim described it, “a constellation of pinpricks” in the data layer of the disc.
How do CD discs work?
It takes a very precise laser beam focused on the data track as the CD spins rapidly around. The laser beam passes through the polycarbonate layer and reflects off the aluminum layer. As it does so, a sensor detects changes in the laser beam’s reflection, since the bumps cause the laser to reflect differently.
Which way do CDs spin?
counterclockwise
In a typical compact disc player, the disc spins counterclockwise, and the constat speed of the surface at the point of the laser-lens system is 1.3 m/s.
How is a DVD different from a CD?
A Digital Versatile Disc or Digital Video Disc (DVD) is similar to a CD-ROM in that you can only read data from it. The main difference is that the DVD can store much more data than a CD-ROM, CD-R, or CD-RW.A DVD+R can only record data once, then the data becomes permanent on the disc.
Does a DVD play from the center out?
Like a CD, the data on a DVD is encoded in the form of small pits and bumps in the track of the disc.On single-layer DVDs, the track always circles from the inside of the disc to the outside. That the spiral track starts at the center means that a single-layer DVD can be smaller than 12 centimeters if desired.
Should CD be stored vertically or horizontally?
Discs are best stored upright (like a book) in “jewel” cases that are designed specifically for CDs/DVDs. Ideally, store the cases in plastic or steel containers manufactured specifically for the type of medium in cool, dry storage that is free of large temperature fluctuations.
Do CD binders scratch CDs?
They will scratch CDs.
What are CD inserts called?
Liner notes (also sleeve notes or album notes) are the writings found on the sleeves of LP record albums and in booklets which come inserted into the compact disc jewel case or the equivalent packaging for cassettes.
Do CDs have grooves?
CDs are easily scratched, and should never be cleaned with just any cloth. CDs should be cleaned radially: not along the grooves, but at right angles to the direction of the grooves. If a smear, however small, should remain on the CD, running along the direction of the grooves, much information would be lost.
What are the two sides of a CD called?
Regardless of the number of panels, the side of the insert that includes the front is called the Outside. The opposite side is referred to as the Inside.
How long can a CD last?
The relative stability of optical disc formats
| Optical disc formats | Average longevity |
|---|---|
| CD (read-only, such as an audio CD) | 50 to 100 years |
| CD-RW (erasable CD) | 20 to 50 years |
| BD-RE (erasable Blu-ray) | 20 to 50 years |
| DVD+R (silver alloy metal layer) | 20 to 50 years |
Do CDs lose quality over time?
Do CDs lose quality over time? – Quora. Yes. Eventually they will degrade to zero.
Can you repair disc rot?
A disc affected by CD rot cannot be repaired, it must be replaced. Fortunately this damage is rare and the manufacturer most affected by this has stated that it will replace any such CDs.
What do you use to read CDs and DVDs?
In the simplest terms, an optical drive is the piece of hardware that lets a device read and interact with a disc. These discs can be CDs, DVDs, Blu-rays, game discs, and more. All optical drives are based on the same fundamental technology.