Chapter Five · Part 2: The Network
Networks
Almost everything you do online needs your computer to talk to another computer. This chapter is where the machine stops being alone — how computers connect, how each one is found, how data crosses the gap, and the small network you already own at home.
So far this course has stayed inside one machine — its parts, its operating system, its programs. But the moment you open example.com, that single machine can't do the job alone. The page lives on a different computer, somewhere else, and yours has to reach it. That reaching-across is what a network is, and it's where the second half of the course begins.
This chapter builds the idea in four steps. First, why computers connect at all. Then how one computer is picked out from the millions of others — every device has an address. Then how the data actually crosses the gap, broken into small pieces called packets. And finally the small network you already own: the one your phone and laptop share at home, and the box at its center that opens the door to everything else.