Concepts explained
The Cloud Is Actually a Building
We 'upload photos to the cloud'. Where in the cloud? There is no cloud. The photo sits in a computer inside some building. 'Cloud' is a pretty word for someone else's computer. The series closes with that building, and the road to it.
How it gets there — chopping the letter
Start with the journey. The photo does not travel whole. It is chopped into thousands of small parcels, each stamped with an address and a sequence number. The parcels find their own way, sometimes by different roads, and are reassembled in order on arrival.
A missing parcel is simply asked for again; a damaged one is caught by piece five's check numbers. That is why a photo can round the far side of the Earth without losing a dot.
The first trial of this scheme came in the autumn of 1969. A computer in Los Angeles was typing LOGIN to one 600 kilometres away — and after the L and the O, the far machine crashed. The internet's first word is therefore 'LO'.
The road runs under the sea, not through the sky
Parcels crossing between continents seem like satellite work, but almost all of them go under the sea — optical-fibre cables on the ocean floor, light running inside glass the width of a hair. The light of the light series, moonlighting here as a postman.
Piece five called an internet round trip 'a voyage of years' — in processor time. On a human clock the far side of the Earth is 0.1 to 0.2 seconds away, because the trip is made at light speed through glass.
Into the building
Where the parcels land is a data centre: a warehouse-shaped building where hundreds of thousands of computers sit racked, running day and night. Every search, photo and video is a round trip to somewhere in such a building.
Piece seven's AI lives here too. The training that turns billions of knobs, and the answering of your questions — chips in this building do it. The phone merely sends the question and displays the reply.
A little further in
The price of the cloud
The building's biggest job is not calculation but the war on heat. Vast cooling plants run alongside the racks, and one large data centre draws electricity like a small city. Hence the sites in cool countries, by rivers, even under the sea.
And one thing has bent away from the original design. Removing the centre was the internet's strength — yet today's internet leans heavily on a few companies' buildings of this kind. The roads still have no centre; the destinations have grown one back.
Looking back over eight pieces
The story that began in piece one has arrived here. A switch that knows only on and off (1) learned to hold numbers (2), had human words translated down to it (3), became a machine for anything (4), walked hundreds of millions of steps inside a blink (5), gained thousands of helpers (6), learned what no one taught it (7), and wrapped the Earth by way of the sea floor (8).
And the first fact never changed. This Earth-sized machine still knows exactly two things: on, and off. The knowing was always ours — the ones who read it.
The question that remainsThe switch still has only two states. What is it, then, that we have built on top?