CD (Compact Disk) Writer

A CD is a standard medium for distributing large quantities of data.

In 2000, Napster (file-sharing program) became one of the biggest news stories around. With Napster and other file-sharing programs, you could obtain an MP3 version of any song you wanted at no cost. Recording companies distributing their products weren’t making any profit.

http://mynapster.sourceforge.net/

As profit for music CD(s) plummeted, electronics manufacturers and retailers soon discovered that around 1999, 2000 and early 2001, sales of CD burners and blank CD-recordable discs skyrocketed.

Companies were now making money by selling, not song CD(s) but more blank CD-recordable discs and CD burners.

http://www.tdk.com/cdburners/index.html

The CD: Most of a CD is consisted of injection-moulded piece of clear polycarbonate plastic.

The process of writing data into a CD: The plastic is hard-pressed with a high-powered laser to etch microscopic bumps into photo resist material. The bumps are set as a single, continuous, extremely long spiral trail of data. Once the clear piece of polycarbonate is formed, a thin, reflective aluminium layer is sputtered onto the disc, covering the bumps. Then a slight acrylic layer is sprayed over the aluminium to guard it. The label is then printed onto the acrylic.

http://www.howstuffworks.com/cd1.htm

A CD has a single spiral track of data, circling from the inside of the disc to the outside.

http://www.howstuffworks.com/cd1.htm

Reading Data: A laser is sent across the CD through the polycarbonate layer in finding and reading the small bumps of data. The laser while passing reflects off the aluminium layer and hits an electronic device that detects changes in light. If the laser comes across the bumps, it reflects light differently than the "lands" (the rest of the aluminium layer), and the electronic 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.

Storing Data:

A CD can store up to 74 minutes of music, so the total amount of digital data that must be stored on a CD is:

44,100 samples/channel/second x 2 bytes/sample x 2 channels x 74 minutes x 60 seconds/minute = 783,216,000 bytes

To fit more than 783 megabytes (MB) onto a disc only 4.8 inches (12-cm) in diameter requires that the individual bytes be very small. By examining the physical construction of a CD, you can begin to understand just how small these bytes are.

To write to a CD, much software is available on the market, which help to store Data in supported format. It is quite useful, and ultimately very cheap to store, and to transfer files across.

References:

http://wt.xpilot.org/publications/linux/howtos/cd-writing/html/

http://www.howstuffworks.com/cd-burner.htm