A computer used to be a person
For about two hundred years, a computer was somebody's job title. The word meant a person who did sums by hand, and teams of them worked out navigation tables, tide charts and artillery ranges — later, the orbits that put spacecraft round the Earth. Only in the 1940s did it start to mean a machine instead.
The machines were not immediately impressive. ENIAC, the first general-purpose electronic computer, weighed roughly thirty tonnes and filled a room; a phone in your pocket now outruns it millions of times over. This puzzle gathers what that room eventually shrank into — the MONITOR and KEYBOARD you touch, the PROCESSOR and MEMORY you never see, and the LAPTOP or DESKTOP holding it all together.
The brain, the desk and the filing cabinet
Three parts do most of the work, and the quickest way to tell them apart is to picture an office. The PROCESSOR is the worker: it follows instructions, billions of them every second, and does nothing else. MEMORY is the desk — big enough to spread out whatever you are working on right now, and swept completely clean the moment the power goes off. The HARDDRIVE is the filing cabinet: slower to reach into, but it keeps what you put there.
That is why an unsaved document vanishes when a LAPTOP dies. It only ever existed on the desk. It is also why a REBOOT fixes so much — it clears the desk and starts again — and why a BACKUP is the only real protection, because filing cabinets fail too.
Where the names came from
Nearly every word here has a story behind it. The MOUSE was built in 1964 by Douglas Engelbart: a wooden block with two wheels and a CABLE trailing from the back like a tail, which is exactly how it got its name. The KEYBOARD is older still — the QWERTY layout was designed in the 1870s for mechanical typewriters, was never meant to help anybody type faster, and we have simply kept it ever since. PIXEL is short for 'picture element', the smallest dot a SCREEN can light up.
Even switching on carries a buried joke. Starting a machine is 'booting' it — short for 'bootstrapping', from the old image of hauling yourself up by your own bootstraps — because a computer has to somehow load the program that lets it load programs. Every REBOOT re-runs that small miracle.
The mix-up worth clearing up
If one thing confuses people about computers, it is MEMORY. Shops advertise a phone with '256GB of memory' when they mean storage, and the two are genuinely different: memory is the workspace, storage is where files live. Ask why a computer feels slow and most people say it is 'full' — but a full HARDDRIVE and a shortage of memory are different problems with different fixes.
Sorting that out is a satisfying five minutes in a computing lesson, and the rest of the vocabulary falls into place after it: why a SCANNER is an input and a PRINTER an output, why a MODEM is not the same thing as a router, and why the CURSOR blinking in a WINDOW is only software drawing on a grid of dots.