What is an operating system?
The short answer
An operating system (OS) is the main software that runs your computer, phone, or tablet — it sits between you and the hardware and makes everything else work.
What does it actually do?
Without an operating system, your device is just a pile of electronics with no way to interact with it. The OS handles all the basics:
- Runs your apps — every program you open goes through the OS
- Manages the screen, keyboard, mouse, and touchscreen so you can actually use the device
- Controls memory and storage — deciding which apps get resources and where files are saved
- Connects to the internet, Bluetooth, and other devices
- Keeps things secure by managing user accounts, permissions, and updates
Think of it as the manager of a building. You don’t interact with the plumbing and wiring directly — the manager handles all of that so you can just live there.
Common operating systems
You’re already using one. Here are the most popular:
- Windows — runs on most desktop and laptop computers
- macOS — runs on Apple’s Mac computers
- iOS — runs on iPhones
- Android — runs on most non-Apple smartphones
- ChromeOS — runs on Chromebooks
- Linux — popular with developers and servers
Do you need to worry about it?
Usually, no. Your operating system mostly works in the background. The main thing you should do is keep it updated. OS updates fix security holes and bugs, and skipping them can leave your device vulnerable.
How to check for updates
- Windows: Settings > Windows Update
- Mac: System Settings > General > Software Update
- iPhone: Settings > General > Software Update
- Android: Settings > System > Software Update
If your device feels slow or glitchy after many years, it may be because the latest OS version is too demanding for older hardware. That’s usually a sign it’s time for an upgrade.