About This Quiz
Compact discs are a popular storage device for both music and computer files. But how much do you really know about them? Take our quiz to find out!A CD can hold a little over 783 megabytes of data, or about 74 minutes of music.
The primary material in a compact disc is clear polycarbonate plastic.
Information on a CD is arranged in a series of bumps that begins at the center of the disc and spirals out to the edge.
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The bumps would only be .5 microns wide, but the string would extend nearly 3.5 miles long!
A tracking system aligns the laser in a CD player to a CD's data track.
Data on CDs is encoded with eight-fourteen modulation (EFM), which converts 8-bit bytes into 14 bits.
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Compact discs store information as a series of 1s and 0s, also known as digital information.
CDs use interleaving to store data non-sequentially. CD drives read the data and then un-interleaves the information to make sense of it all.
CDs have a thin coating of aluminum behind the polycarbonate plastic. The CD drive's laser reflects off the aluminum and is detected by a sensor.
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The CD drive has to spin the CD slower as the laser moves outward. That's because the bumps on the outer edge move faster than the ones in the inner edge -- they cover a greater distance in the same amount of time as the inner bumps.