Buses have to solve a very thorny problem that does not arise within the CPU, which is how to coordinate electronic events. Within the CPU, the designer can simply make sure that the longest data path governs the maximum amount of time it takes for signals to travel from one end of the logic circuit to the other. In a bus, many diverse components must fit together and work without interference, and they cannot be manufactured to be in perfect accordance with each other's timing.

So a mechanism from the world of music is used -- the conductor. In a symphony orchestra, the conductor stands on a podium where all the musicians can see him or her. By waving a wand in rhythmical fashion, the conductor establishes a beat which is used to coordinate the timing of all the events in the orchestra. The violins, for example, see a sheet of music in front of them divided into bars filled with beats. These bars and beats divide time up into units so that music can progress. It is the job of the conductor to say, by waving the wand, just exactly how long a single beat lasts.