Invention

• James T. Russell of Bremerton, Washington invented the digital compact disc in the late 1960s and patented the first digital-to-optical recording and playback system in 1970.
  
  

Development

• Sony and Philips worked together on the new format beginning in 1979. In 1982, Sony introduced the first CD player, the CDP-101.
  
  

Function

• The CD player finds and reads data stored as bumps on the discs. The player focuses a laser on the track of bumps, and the beam reflects back and hits an opto-electrical device that detects changes in light. Bumps are read as O's and flat areas as 1's in the digital binary code.
  
  

Audio Quality

• According to the Philips Research website, CDs provide channel separation and a signal-to-noise ratio of higher than 90 decibels, compared to 30 and 60 decibels respectively for analog technology.
  
  

Other Advantages

• Since the reader system of a CD player does involve physical contact, in principle a CD can last forever.