This
article describes some of the mathematics behind the digital revolution. It is
common knowledge that the digital revolution involves storing and transmitting
messages, information or data as numbers instead of more directly as physical
quantities. Why is it, though, that this results in better technology? Why, for
example, is compact disc sound better than the sound of a record or a tape
recorder? Clearly, the answers to questions like this depend on much more than
mathematics, but mathematics plays an important role. This article discusses
one of the ways in which mathematics is involved. Two key concepts will be
explained—error detecting codes and error correcting codes—and illustrated with
two familiar examples—barcodes and ISBN numbers. Finally, a brief introduction
to more sophisticated codes will be given.