|Comparison of DVD and CD-ROM. The Hutchinson Family Encyclopedia, 2000.||"Distance between data tracks (microns) DVD: 0.74; CD: 1.6"||1.6 μm|
|Robertson, James and Suzanne. Complete Systems Analysis: The Workbook, the Textbook, the Answers. Chicago: Desert House Publishing, 2000: 103.||"The distance between two spiral tracks is 1.6 im [sic], therefore if we consider a track width of 0.6 im for a 3.3 im ray, we conclude that there are 15,000 tracks on a CD."||1.6 μm|
|Optical Opulence The Sights & Sounds Of DVD. Smart Computing. Vol. 4, No. 3 (August 2000).||"The distance between tracks on DVD media is a mere 0.74 microns while the distance between tracks on CD media is 1.6 microns."||1.6 μm|
|Goodwin, Michael C. Digital Audio CD and other Selected Digital Technologies Based on Principles of Digital Audio, 4th Ed. by Ken C. Pohlmann and other sources.||"NA and wavelength also determine track pitch (average distance between tracks: 1600 nm for CD and 740 nm for DVD), cutoff frequency, etc. and ultimately disk playing time."||1.6 μm|
|Darvin, Vyacheslav. "3 Dimension" Disc.||"Distance between tracks, micron -- Format CD: 1,6; DVD: 0,74; Modified DVD: 0,8"||1.6 μm|
Today, people all over the world enjoy listening to their favorite music on compact discs. Their sleek, round design and their ability to store numerous songs makes them much more appealing than the old cassettes. The clear, digital quality of the compact disc is also incomparable. But did you ever wonder where the compact disc actually came from and how it works? The answer may surprise you.
Even though CD's are relatively modern, the first few were actually invented back in 1978. It was at this time that the famous electronics companies Sony and Philips teamed up to develop a standard, universal compact disc to hold audio. Two years later a Philips/Sony Compact Disc Digital Audio Standard disc was officially announced. Such a disk was 120 millimeters, could play a maximum of 74 minutes worth of audio, and played at a sampling frequency of 44,100 Hz. The distance between tracks was 1.6 μm. (1 μm = 10−6 m).
Most of the CD's that we listen to right now are enhanced. These new specialized CD's are compatible with both audio CD players and properly configured multimedia ROM's. They can include video clips, still pictures, interviews, discographies, lyrics, and other information, in addition to the recorded music. This shows us that technology only gets better with time. We cannot possibly imagine today what exciting and useful innovations will be around in a mere decade.
Inna Sokolyanskaya -- 2001