Course · Intro
How computers actually work
A computer is a rock we tricked into doing arithmetic with electricity. This course walks the whole machine — from a single on/off switch up to a running program — so the box on your desk stops being magic.
Everyone uses computers; almost no one knows what's happening inside one. This course takes the lid off — not coding, not a tour of products, but the machine underneath. How a thing made only of switches can store a photo, add two numbers, remember, and run the app in front of you. We build it from the bottom: one switch, then logic, then a processor, then code, then the operating system. By the end the box isn't magic — it's a tower of simple ideas stacked very high, and a tech headline reads like a story you understand instead of weather you endure.
What you'll be able to do
- Explain how a computer represents everything — numbers, text, images, sound — as nothing but on/off switches.
- Trace how plain switches combine into logic that can add, compare, decide, and remember — and how that scales into a processor.
- Follow what actually happens when a program runs: instructions, the fetch-execute loop, and the ladder of abstraction from a click down to electricity.
- Read a tech-spec or chip headline and know what is really being claimed — and what 'a bigger number' does and doesn't buy you.
Course complete
You finished every lesson. Put your name on it.
Module 1 — Everything is switches
The bit: on or off
Explain that a computer stores and moves everything as one of two states (on/off, 1/0), and why two states — not ten — is the choice that makes it reliable.
Counting in twos: binary
Explain how a handful of on/off switches counts to any number using place values of 1, 2, 4, 8…, and read a small binary number.
From numbers to everything: text, pictures, sound
Explain how the same bits become letters, pixels, and sound once everyone agrees on a code — a number per letter, three numbers per dot of colour, thousands of numbers a second for sound.
Module 2 — Switches that think
The logic gate: a switch that decides
Explain how a transistor is a switch other switches control, and how gates (AND, OR, NOT) turn inputs into one decided output — the atom of all computation.
Gates that do maths: the adder
Explain how a few gates wired together add two binary numbers, carry and all — showing arithmetic is just logic, not magic.
Memory: holding a bit still
Explain how a loop of gates can hold a value instead of just reacting to it, and why being able to remember is what separates a computer from a calculator.
The processor: fetch, decode, execute
Explain the loop at the heart of every computer — fetch an instruction, work out what it means, do it, repeat — run billions of times a second.
Module 3 — From wires to software
Instructions: what the chip really understands
Explain that a processor knows only a small fixed set of dumb instructions — add, move, compare, jump — and that every program is a long list of them.
Abstraction: how we stopped writing in 1s and 0s
Explain the ladder from machine code to assembly to a high-level language to an app, and why each layer hides the one below — the central trick of all computing.
The operating system: who's in charge
Explain what an operating system does — sharing the one processor, the memory, and the devices among many programs — and why no app talks to the hardware directly.
Why a computer feels fast or slow
Explain the memory hierarchy — registers, cache, RAM, disk — and why 'more gigahertz' or 'more memory' sometimes helps a lot and sometimes does nothing.
Module 4 — The machine in the world
Why computers kept getting faster — and the wall
Explain in plain terms the decades of doubling (more, smaller switches) and the physical limits now biting — heat, the size of atoms — and why chips went to many cores instead.
Capstone: reading a spec sheet
Decode a real-style computer or chip headline — '3 nm, 8-core, 16 GB, 1 TB SSD' — using everything the course taught, and judge what's worth paying for.