Ask A Scientist© Computer Science Archive

Index Key:   COM029
Author:      nathaniel p kravitz
Subject:     How compact discs work.
How do compact disks (cd's) work?

Response #:  1 of 1
Author:      asmith
I am not sure of the details, but basically data is encoded on the disk by
making little marks (I think relatively deep pits) on the shiny side, and
then a laser shining on the surface can look and see if there is one of
these marks there or not.  Magnetic recording works in a kind of similar way
- the surface is magnetized one way or another.  This gives one binary "bit"
of information, and then assuming the hardware that created the disk is
compatible with the hardware that is reading it, you can convert from these
binary bits back into the original data that was encoded on the CD, and play
it as sound or get the computer information off it.