Clock

At the heart of every computer is a clock. It may not tell time, or stamp date/time onto files (though most computers have those now too), but it keeps the central processor on schedule. The 40 Mhz 68040 chip in the computer I'm typing on has as its main control a clock chip sending it a signal 40 million times a second to tell it to move on to the next instruction. Life at this pace seems painful to us, but the computer can handle it. Other chips run at 66 or even 99Mhz. The information runs in and out at an ever faster pace, processing, sorting, and calculating in instants.