What is a computer?
Quick answer
A computer is an electronic machine that takes in data (input), processes it by following instructions (programs), stores it, and produces results (output). Laptops, smartphones, game consoles and the chips inside cars and washing machines are all computers.
Every computer, from a supercomputer to a smartwatch, follows the same basic cycle: input → processing → storage → output. You press a key (input), the processor works out what to do (processing), the result is saved (storage), and a letter appears on screen (output).
The main parts
| Part | What it does | Everyday comparison |
|---|---|---|
| CPU (processor) | Carries out instructions | The brain |
| RAM (memory) | Holds what you’re working on right now | A desk |
| Storage (SSD or hard drive) | Keeps files when the power is off | A filing cabinet |
| Motherboard | Connects everything | The nervous system |
| Input devices | Keyboard, mouse, touchscreen, microphone | Senses |
| Output devices | Screen, speakers, printer | Voice and hands |
Modern processors contain several cores that work in parallel. Here’s how to check how many cores yours has.
Hardware and software
Hardware is the physical machine. Software is the set of instructions that tells it what to do: the operating system (like Windows, macOS or Android) manages the hardware, and apps do specific jobs. Not sure which Windows you’re running? Check your Windows version.
Types of computers
- Personal computers: desktops and laptops
- Mobile devices: smartphones and tablets
- Servers: powerful computers that run websites and cloud services
- Supercomputers: used for weather forecasting and scientific simulations
- Embedded computers: tiny chips inside cars, appliances and medical devices
Still curious?
Jump to a random question from the archive.