1. Lesson: Your computer: what it is and how it works
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1. Your computer: what it is and how it works
Week 1 of 2
What you will be able to do
- Name the main parts of a computer and say what each one does.
- Tell hardware from software, and say what an operating system is.
- Turn a computer on, sign in, and shut it down properly.
- Know which kind of computer you have (Windows, macOS, ChromeOS) and what a phone can and can't do for this course.
Why this matters
Everything else in this course, and in every IT course after it, assumes you are comfortable sitting in front of a computer. You don't need to know how it is built inside. You only need a simple picture of the parts and what they do, so that the rest makes sense and nothing feels like magic.
1. What a computer does
A computer does four things, over and over:
| Step | What happens | Example |
|---|---|---|
| Input | You give it information | You type a word, click the mouse, speak into the microphone |
| Processing | It works on that information | It checks the spelling of the word |
| Storage | It keeps information for later | It saves your letter as a file |
| Output | It shows you the result | The letter appears on the screen, or comes out of a printer |
Phones, tablets, laptops and desktop computers all work this way. A phone is a small computer.
2. Hardware and software
Hardware is the part you can touch:
| Part | What it does |
|---|---|
| Screen (monitor) | Shows you what the computer is doing |
| Keyboard and mouse or touchpad | Let you type and point |
| Processor (CPU) | The "brain" that does the work |
| Memory (RAM) | Short-term working space; it is emptied when the computer turns off |
| Storage (hard drive or SSD) | Long-term space for your files and programs; it keeps them when the computer is off |
| Ports (USB, HDMI, headphone) | Places to plug in other devices: a flash drive, a printer, a projector |
| Battery and charger (laptops) | Power; a laptop runs for some hours without a cable |
Software is the instructions that tell the hardware what to do. There are two kinds:
- The operating system (OS) runs the whole computer: Windows, macOS (on Apple computers), ChromeOS (on Chromebooks), or Linux. On phones, Android or iOS.
- Applications (apps, programs) do particular jobs: a web browser, a word processor, a music player.
Memory or storage? Think of an office. Memory is the top of your desk: what you're working on now, cleared when you go home. Storage is the filing cabinet: everything you've kept, still there tomorrow. Shops describe both in gigabytes (GB), but they are different things.
3. Turning it on, signing in and shutting down
- Turn on: press the power button once (on a laptop it is usually above the keyboard or on the side). Wait until the sign-in screen appears.
- Sign in: choose your account and type your password or PIN, then press Enter. Your password keeps other people out: never share it.
- Shut down properly: on Windows, select Start (the Windows logo) → Power → Shut down. On a Mac, select the Apple menu → Shut Down. On a Chromebook, select the clock → power icon.
Don't just pull the plug or hold the power button: the computer may lose work that wasn't saved, or damage files. Hold the power button for ten seconds only if the computer has stopped responding completely (topic 10 shows what to try first).
Power cuts. Where electricity is unreliable, save your work often (topic 3), keep a laptop charged, and use a surge protector or stabiliser for a desktop computer.
4. Which computer do you have?
Look at the bottom-left of the screen. A Windows logo means Windows; an Apple logo at the top-left means macOS; a round launcher at the bottom-left on a laptop that says "Chromebook" means ChromeOS. All three work for this course.
Only have a phone? You can do most of this course on a smartphone: the browser, email, safety, and cloud documents topics work on a phone. Typing, files and folders, and the later IT courses need a laptop or desktop computer. If you don't own one, a cyber café, a library, a school or a friend's computer will do for now.
Watch
Computer Basics: What Is a Computer and How Does It Work?
LearnFree · 3 min. What a computer is and how it works.
Computer Basics: Getting to Know Laptop Computers
LearnFree · 2 min. The parts of a laptop.
COMPUTER BASICS: Understanding Operating System
ACOnetwork · 2 min. What an operating system does.
Try it
- Turn your computer on and sign in. Write down which operating system it uses.
- Find these parts on your own computer: screen, keyboard, mouse or touchpad, at least one USB port, the power button.
- Find out how much storage your computer has. Windows: Start → Settings → System → Storage. Mac: Apple menu → About This Mac → More Info → Storage.
- Shut the computer down properly, then turn it on again.
Check your understanding
- What are the four things a computer does?
- What is the difference between memory (RAM) and storage?
- Is a web browser part of the operating system or an application?
- Why shouldn't you just pull the plug to turn a computer off?