1.2 Measuring computing power

For physical machines, we can compare the power of different machines by measuring the amount of mechanical work they can perform within a given amount of time. This power can be captured with units like horsepower and watt. Physical power is not a very useful measure of computing power, though, since the amount of computing achieved for the same amount of energy varies greatly. Energy is consumed when a computer operates, but consuming energy is not the purpose of using a computer.

Two properties that measure the power of a computing machine are:

  1. How much information it can process?

  2. How fast can it process?

We defer considering the second property until Part II, but consider the first question here.