In computers, sequence is everything. The system clock synchronizes the tasks
in a computer, like loading data before manipulating it, etc. The system
clock is a circuit that emits a continuous stream of precise high and low
pulses that are all exactly the same length. One clock cycle is the time that
passes from the start of one high pulse, until the start of the next. If several
events are supposed to happen in one clock cycle, the cycle is subdivided by
inserting a circuit with a known delay in it, thus providing more highs and more
lows.