A connection
How did Wheel and Cart lead to Packet switching?
8 steps · 5 domains · 5,465 years
- Wheel and Cart~3,500 BC · 3,500 BCA disc turning on an axle that converts dragging into rolling, cutting the effort of moving a heavy load overland many times over.
- which needed it — made it thinkable ↑Lever, Pulley, Screw, Gear~6,000 BC (levers and ramps) · 6,000 BCThe simple machines — lever, ramp, pulley, screw, gear — that trade force for distance, letting ordinary human muscle move loads far beyond its natural limit.
- made it thinkable ↓Mechanical Clock~1300 AD (escapement) · 1300 ADA falling weight checked by an escapement that releases its power one tick at a time — the first machine to chop time into equal, countable beats.
- which needed it — made it possible ↑Iron Smelting (Bloomery)~1,500 BC · 1,500 BCReducing iron ore to workable metal in a charcoal-fired clay furnace.
- made it makeable ↓Electric arc welding1881 (Benardos's carbon arc) · 1881 ADJoining metal by drawing a sustained electric arc between an electrode and the workpiece — a spot of controlled lightning, several thousand degrees hot, that melts the edges of two steel pieces so they flow together and freeze as one continuous metal.
What the arc melts and re-freezes is smelted iron and steel; the craft is a way of locally re-liquefying the smith's metal and letting it solidify as one piece.
- which needed it — made it possible ↑Electric Generator1831 AD · 1831 ADFaraday's discovery that moving a magnet past a wire induces current — mechanical motion converted directly into electricity.
An arc needs a strong, steady current — tens or hundreds of amperes at low voltage — which only a dynamo could deliver; arc welding was physically impossible before the generator existed.
- made it makeable ↓Vacuum Tube (Triode)1906 AD · 1906 ADA light bulb's evil twin: electrons boiled off a hot filament in a vacuum, steered by a metal grid — the first electronic amplifier and switch.
- made it possible ↓Stored-program computer1945 AD (EDVAC report) · 1945 ADA computer whose instructions live in the same read-write memory as its data, encoded as ordinary numbers. Because the program is just numbers in memory, the machine can be given an entirely new task by loading new numbers — no rewiring — and can even read and modify its own instructions.
Fast read/write memory and logic needed electronic switching, and the vacuum tube supplied it years before the transistor existed.
- made it possible ↓Packet switching1965 AD (Baran 1964, Davies 1965) · 1965 ADA way to move data by chopping every message into small, separately addressed pieces — packets — and letting each one find its own way across a shared network, hopping node to node until it arrives, where the pieces are reassembled. No caller ties up a dedicated line; the network's capacity is shared, packet by packet, among everyone at once.
Each switching node is itself a small computer that reads a packet's address, decides where to send it next, and forwards it — store-and-forward routing that only a programmable machine can perform.
Every link in this chain is a verified dependency — not a trivia association. Explore either end: Wheel and Cart or Packet switching.