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Different Operating Systems (OS)

A friendly tour of the "boss program" on every computer

An operating system (we say "OS" for short) is the main program that runs a computer. Think of it like the principal of a school. You do not see the principal every minute, but they make sure everyone gets a turn, nobody breaks the rules, and the whole building keeps working.

What does an OS actually do?

Every device has layers, like a sandwich. You are on top. The hardware (the real metal and plastic parts) is on the bottom. The OS sits in the middle and passes messages both ways.

YOU            tapping, typing, clicking
 |
APPS           games, web browser, drawing program
 |
OPERATING      shares the screen, memory, and chips
SYSTEM         fairly between all the apps
 |
HARDWARE       screen, battery, storage, the "brain" chip (CPU)

The OS also:

  • Starts up the computer when you press the power button (this is called booting).

  • Remembers your files and puts them in folders.

  • Lets apps take turns using the brain chip so nothing freezes.

  • Keeps apps in their own space so one crashing app does not break the others.

The big operating systems

Windows

  • Made by: Microsoft

  • Runs on: most laptops and desktop computers (many different brands)

  • Costs money? Usually it comes already on the computer you buy.

  • Good for: PC games, schoolwork, and offices. Lots of programs are made for it.

  • Fun fact: The newest version is Windows 11. It has been around since the 1980s, so your grandparents may have used it.

macOS

  • Made by: Apple

  • Runs on: only Apple computers (MacBook, iMac, Mac mini)

  • Costs money? It comes free on every Mac, but Macs cost more to buy.

  • Good for: drawing, video editing, music, and anything where you also own an iPhone or iPad, because they work together nicely.

  • Fun fact: Every version is named after a place in California, like "Sequoia" or "Sonoma."

Linux

  • Made by: thousands of volunteers around the world, plus some companies. Nobody "owns" it.

  • Runs on: almost anything, from tiny robots to giant supercomputers.

  • Costs money? No. It is free and open source (anyone is allowed to look at how it is built and change it).

  • Good for: tinkering, learning how computers work, and running websites. Most of the internet's servers use Linux.

  • Flavors: Linux comes in many versions called distributions ("distros" for short). Friendly ones for beginners are Ubuntu, Linux Mint, and Fedora.

ChromeOS

  • Made by: Google

  • Runs on: Chromebooks (cheaper, lighter laptops). Many schools use these.

  • Costs money? It comes on the Chromebook, which is usually inexpensive.

  • Good for: web browsing, Google Docs, watching videos, and school. It stays simple and updates fast.

  • Fun fact: It is actually built on top of Linux.

Android

  • Made by: Google (with lots of phone companies adding their own touches)

  • Runs on: most phones and tablets that are not made by Apple (Samsung, Pixel, Motorola, and more).

  • Costs money? No, it comes on the phone.

  • Good for: phones and tablets. You get apps from the Google Play Store.

  • Fun fact: Android is also built on top of Linux, and old versions were named after desserts like "KitKat" and "Oreo."

iOS and iPadOS

  • Made by: Apple

  • Runs on: iPhone (iOS) and iPad (iPadOS) only.

  • Costs money? No, it comes on the device.

  • Good for: phones and tablets that work smoothly with Macs and AirPods. Apps come from the App Store.

  • Fun fact: Apple checks every app before it is allowed in the store, which is why there are fewer surprises.

Some bonus ones

Name

Where you might meet it

Raspberry Pi OS

A tiny, cheap computer the size of a playing card that kids use to learn coding and build projects.

BSD (FreeBSD, OpenBSD)

A cousin of Linux. Quiet and sturdy. Runs some game consoles and big company servers.

Steam Deck (SteamOS)

A handheld game machine. Its OS is a special kind of Linux.

Quick compare chart

OS

Made by

Runs on

Free?

Best at

Windows

Microsoft

Most PCs

Comes on PC

PC games, offices

macOS

Apple

Apple computers

Comes on Mac

Art, video, Apple gear

Linux

Volunteers

Almost anything

Yes

Tinkering, servers

ChromeOS

Google

Chromebooks

Comes on it

Web and school

Android

Google

Non-Apple phones

Comes on it

Phones, tablets

iOS

Apple

iPhone / iPad

Comes on it

Phones, tablets

How do I pick one?

There is no single "best" OS. The right one depends on what you want to do.

Is it a phone or tablet? ------------------> Android or iOS
                                             (whichever brand you like)

Want a cheap laptop mostly for the web
and school? --------------------------------> ChromeOS

Do you play a lot of PC games? -------------> Windows

Do you already own an iPhone and want
everything to match? ----------------------> macOS

Do you like to take things apart, change
settings, and pay nothing? ----------------> Linux

Word bank

operating system (OS)

The main program that runs a computer and shares its parts between all the apps.

app

A smaller program you open to do one thing, like a game, a browser, or a calculator.

hardware

The physical parts you can touch: screen, battery, chips, storage.

boot

What the computer does when it turns on and loads the OS.

update

A free change the OS maker sends out to fix problems and add features.

open source

Software whose "recipe" is public, so anyone may read it, share it, and improve it. Linux is the famous example.

distribution (distro)

One packaged version of Linux, such as Ubuntu or Linux Mint.

Try it yourself