They exist in traffic lights, elevators, water, gas, and electricity control systems. They re in medical equipment and military and navigation systems. America's air traffic control system is dependent upon them. They re located in the track beds of railroad systems and in the satellites that circle the earth. Global telecommunications are heavily dependent on them.
Modern cars contain about two dozen microprocessors.
The average American comes in contact with seventy microprocessors before noon every day. Many of these chips aren't date sensitive, but a great number are, and engineers looking at long ago installed systems don't know for sure which is which. To complicate things further, not all chips behave the same. Recent tests have shown that two chips of the same model installed in two different computers but performing the same function are not equally sensitive to the year-end problem. One shuts down and the other doesn't.