CD-R | CD/RW | Inside | Install

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The right CD

A CD is a simple piece of circular plastic, impressed with microscopic bumps arranged as a single, continuous, extremely long spiral track of data, like a vinyl record. Once the clear piece of plastic is formed, a thin, reflective aluminum layer is applied to the disc, covering the bumps. Then a thin plastic layer is sprayed over the aluminum to protect it. The label is then printed onto the acrylic. Unlike vinyl records, the data is read from the inside of the disc to the outside. A laser beam is directed at the disc’s surface, or "land", and if it is reflected back, the reader interprets a 1; if there is no reflection, the reader sees a 0.

CD-R

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CD-R (Compact Disc-Recordable) uses the same principle to read a disc as a CD, but CD-Rs are made differently. A layer of organic dye sits on top of a reflective layer. To record data, a high-intensity laser beam burns bumps in the dye layer. Like the pits on a CD, the bumps send back much less light, and the reader interprets them as a 0. A regular CD and a CD-R have the same reflectivity strength, so a CD-R is readable on most standard CD devices. With CD-R, once the bumps are burned in, you’ve created a permanent record — there’s no turning back. 

CD/RW

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CD-RW (Compact Disc-Rewriteable) actually allows write, erase and rewrite data to a disc. CD-RW uses phase-change technology. Instead of a dye layer, a CD-RW has a thin film of material made of an alloy containing silver, indium, antimony and tellurium that can change from a highly reflective crystalline state to a less reflective “amorphous” state that is the equivalent of a pit on a CD. 
To create "pits" a laser heats spots on the disc. When the spots cool, they lose their reflective quality. A CD-RW recorder can also generate a cooler laser temperature, which returns the spots to their original crystalline state. 
One drawback with CD-RW: they have about one-third the reflectivity of a CD or CD-R, making them too dim for a standard CD reader to scan. New multireader drives are starting to come onto the market which can automatically adjust to the reflectivity level of the disc and read all types of discs.

Inside a CD player

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The CD player has the job of finding and reading the data stored as bumps on the CD. The drive consists of three fundamental components:

1. A drive motor spins the disc. This drive motor is precisely controlled to rotate between 200 and 500 rpm depending on which track is being read.
2. A laser and a lens system focus in on and read the bumps.
3. A tracking mechanism moves the laser assembly so that the laser's beam can follow the spiral track. The tracking system has to be able to move the laser at micron resolutions.

The CD player focuses the laser on the track of bumps. The laser beam passes through the polycarbonate layer, reflects off the aluminum layer and hits a sensor that detects changes in light. The bumps reflect light differently than the "lands" (the rest of the aluminum layer), and the sensor detects that change in reflectivity. The electronics in the drive interpret the changes in reflectivity in order to read the bits that make up the bytes.

A tracking system continually moves the laser outward from the center of the disc, the bumps move past the laser faster -- this happens because the linear, or tangential, speed of the bumps is equal to the radius times the speed at which the disc is revolving (rpm). Therefore, as the laser moves outward, the spindle motor must slow the speed of the CD. That way, the bumps travel past the laser at a constant speed, and the data comes off the disc at a constant rate.

Installation

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CD-ROM, CD-R, or CD/RW  - they all are installed the same way. Most of the CD drives are the IDE type. Some are SCSI, but typically these are used in higher-end servers rather than in most workstation PCs.First of all, read the manual to familiarize yourself with the installation process. There may be some procedures particular to your drive that will be listed here. This page serves only as a general outline. 

Also, just a reminder to remember to rid yourself of all static electricity before messing around with your computer. Just touch the metal frame (inside the case with the power cord plugged into a grounded outlet), or some other metal piece of furniture. If possible, don't work on a carpeted floor.

1. Make sure the computer is turned off. Unplug it and disconnect it from the wall outlet.
2. Remove the cover from the drive bay you want to install the drive into. This is done by taking the case cover off and pushing the little tabs that hold the bay cover in toward the center of the computer so that they are no longer holding it. 
3. Remove the drive from the wrapper. It is packaged in an anti-static bag to protect it from static shock coming from you!
4. Adjust the jumpers on the or back of the drive according to the manual (master, slave, or cable select). Most drives come jumpers configured to make the drive a slave, but you may want to double-check, or change the settings for your situation.
5. Slide the drive into the vacant drive bay. You may need to move other cables out of the way, but don't disconnect them. Don't screw the drive in place yet, as you may need to make some adjustment before anchoring the drive into place.
6. Connect one of the DC power plugs from the power supply to the drive.
7. Attach one of the connectors on the ribbon cable to the drive. Make sure your ribbon cable has the red edge aligned with Pin 1 on the drive. Usually, there is a map of pins printed on the drive which shows which pin is Pin 1.
8. Connect the other end of the ribbon cable to one of your IDE controllers, either on the motherboard, or on a separate interface card. Usually, people connect the cable to IDE2 on the motherboard and have the drive configured as master. This might vary, though, depending on your situation.
   (If you had to use a separate interface card, install it now. Save the screw, use it to fasten the interface card after you have installed it. In most cases, you will not need a separate IDE card, but instead will just use the one on the motherboard.)
9. Install the audio cable that runs from the drive's audio-out to the CD-IN connector on your sound card. This connector is usually well-labeled. Most consist of a series of pins, usually four. Some, such as the AWE64, require you to plug the cable into a port-like connector that is mounted sideways.
10. Turn on your system with the case off in case you need to do anything else.
11. Install the drivers on the discs that came with the drive.
12. If its working, you're done.
    If not, double-check all your work before contacting tech support. Are all cables on tight? Is the software installed correctly? Are all the settings correct on the drive and the board? Do you have the settings correct for that particular IDE channel in your BIOS?  Should you have problems, contact me.