;colony/science / Computers, Visually
⌗ Computers, Visually
Computers, Visually
Where school science stops, we keep going — bits, gates, and the machinery of thought.
Read it your way
Every answer here is written twice. Flip the switch and the page rewrites itself.
Try it now · Plate 24
How do computers count with only 1s and 0s?
Tap the squares; press +1 and watch the carry ripple.
PLATE 24 · EIGHT SWITCHES
Quick set
These 8 bits say
42
Possible values
256= 2⁸
Each square is a switch worth double the one to its right: 1, 2, 4, 8… With just
eight on-or-offs you can spell every number from 0 to 255 — press "A" and you're
looking at how this very page stores the letter A. Try +1 from 255 and watch every
switch flip at once.
Every question
Computers, Visually, answered twice.
Plate 24Open → How do computers count with only 1s and 0s? Everything your computer has ever shown you, this sentence included, is switches that are either on or off. Plate 25Open → How do tiny switches add up to a computer? Your laptop makes no decisions. It makes billions of micro-decisions — each one this simple. Plate 56Open → How does GPS know where you are? Your phone finds itself on the whole Earth to within a few metres — using nothing but the time of day, broadcast by clocks flying 20,000 km overhead. Plate 57Open → How does the internet send a message? Your message doesn't travel as one piece down one wire. It's shredded into numbered packets that scatter across the network by different routes and reassemble at the far end. Plate 58Open → How does encryption keep a secret? Two strangers, shouting across a crowded room where everyone can hear, can still agree on a secret password nobody else learns. The trick is a sum that's easy to do and almost impossible to undo. Plate 75Open → How does a CPU run a program? A processor has no idea what your program is for. It just reads one instruction, does it, reads the next — a dumb little loop, run billions of times a second. Plate 76Open → How do hash tables find things instantly? Looking something up in a million-item store usually means searching. A hash table skips the search entirely: it computes where the thing must be and goes straight there. Plate 77Open → How does compression shrink a file? You can't shrink a file by magic, but most files are full of repetition and predictable patterns. Compression finds that waste and describes it more briefly. Plate 114Open → How does caching make things fast? A computer doesn't fetch your data faster the second time. It just keeps a copy of the stuff you keep asking for right next to it, where reaching for it is almost free. Plate 115Open → How does DNS find a website? Computers can't talk to names, only to numbers. So every time you type a web address, a quiet relay of helpers turns that name into a number before anything loads. Plate 116Open → How does a screen make colour? Your screen has never once produced yellow light. When it shows you yellow, it is lying to your eyes with red and green, and your eyes happily believe it. Plate 117Open → How do computers sort things? A computer can't see a whole list at once and slot everything into place. It can only ever compare two things and maybe swap them. Sorting is that single move, repeated, and the cleverness is all in repeating it less. Plate 118Open → What is a neural network? The simplest neural network doesn't understand anything. It just draws a line, checks which dots it got wrong, and nudges the line a little to fix them. Repeat a few hundred times and that nudging looks a lot like learning. Plate 164Open → How does a QR code store information? A QR code is a tiny map of black-and-white squares. Three corner markers tell the camera where it is, and built-in spare copies let it survive a scribble — up to about a third destroyed and it still reads. Plate 168Open → How does a search engine rank pages? A search engine treats every link as a vote, but not all votes are equal. A page is important if important pages link to it, so importance flows around the web until the numbers settle.
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