Optical disc drive

Some computers have a (secondary) storage device called an optical disc drive. If you have ever bought a playstation/Xbox game from a shop, taken it home an put the disc in your console then you have used and optical disc (the game) and an optical disc drive (where you put the game)
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A computer (unopened)
A computer (opened) - Optical disc drive shown
An optical disc drive

Why is it called an "optical" disc drive?

This disc drive is called an "optical" disc drive because it has a lens in it. If you have ever seen anyone wearing glasses on their face, chances are they bought them from an "opticians" (another word for lens is optics). The optical drive contains an optical lens and a laser beam passes thought this optical lens.
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An optical drive in a laptop

The small blue circle is the optical lens

​Optical media and optical drive

Physical holes in the bottom of a disc

How does an optical drive work?

  1. The spindle spins the optical media (CD, DVD, Blu-ray)
  2. A laser shines though a lens and reflects off the bottom of an optical disc
  3. If the laser shines in a pit, the computer reads a “zero”
  4. If the laser reflects off a land, the computer reads a “one”
Loading Optical drive