Yesterday the class named every part inside one machine. RAM and CPU on the machine side, VRAM and GPU on the card, storage underneath both. Five boxes, one drawing, and every word this unit uses sitting on it. Today that same drawing goes somewhere else. It goes into a building in another state, and it goes there thousands of times over.

Start with the part that is nearest. A phone or a Chromebook talking to an app is doing something that feels like it happens in the air. The word for the part that happens in the air is wifi, and wifi is real, and it is also almost none of the distance. Wifi covers the space between a device and the router on the wall. Call it thirty feet. After the router the signal is in a wire, and it stays in a wire or in a strand of glass for every remaining mile of the trip. There is no point later in the journey where the request goes back into the air and floats the rest of the way.

That wire leaves the building and arrives at a company whose only job is to carry traffic. In this city that company is likely to be Cox. Carry is the honest word for what it does. It does not store anything of yours and it does not answer any question you asked. From there the request joins lines that run between cities, and those lines are the reason a request from New Orleans reaches Dallas in about eleven thousandths of a second rather than instantly. Distance costs time even at the speed of light in glass.

At the far end of those lines is a building. This is the part worth slowing down for, because the ordinary word for it hides it. The ordinary word is cloud. The word suggests something without a location, something spread out, something nobody could point at. None of that is true. The cloud is a building. It has an address. Someone owns it, someone pays its electricity bill, and a person could drive to it.

Inside the building are racks, and inside the racks are machines. Yesterday’s drawing describes every one of them. RAM, CPU, storage, and on many of them a card carrying VRAM and a GPU. Not a different kind of computer. The same kind, in a room, repeated until the room is full, and then repeated in the next room. What makes a data center different from the laptop on the demo cart is how many machines are in it and how much power runs into the building. That is a difference in count, not a difference in kind.

Once that is clear, a question that sounded strange becomes ordinary. When an app answers you, whose computer did the work? Not yours. Yours sent text and drew the answer on a screen. The arithmetic happened on a machine in a building owned by a company, and you were using a fraction of a second of that machine without ever seeing it, naming it, or knowing which city it was in.

Which brings the drawing home. Two machines in a spare room in New Orleans sit on the same map as that building. They have the same parts. They connect through the same kind of wire to the same kind of company. When one of them answers a question it is doing what a machine in the data center does, at a smaller scale, for one classroom instead of ten million people. There is a name for a machine whose job is to answer requests that come from other machines, and the name is server. A rack in a data center holds servers. A machine in a spare room, doing the same job, is also a server.

That is the whole claim of the day, and it is the reason next week is possible. If the cloud were a different kind of thing, a class could not have one. Because the cloud is a building full of ordinary machines, a class can have a very small version of it, and the machines answering next week’s prompts will be two of them, in a house a few miles from this room. The cards in those machines are the 4090 and the 5070 Ti, which are two of the four bars on the ladder from last week.

Three words carry it. A network is what connects machines to each other. A server is a machine whose job is to answer. The cloud is somebody’s servers, in somebody’s building, somewhere.