What is an operating system?

The manager in the middle

A computer is a box of parts: a processor that does the thinking, memory that holds what you are working on, storage that keeps files, a screen, a keyboard and a network connection. On their own, those parts do nothing useful. The operating system (often shortened to OS) is the software that brings them to life and keeps them working together.

A good comparison is the manager of a busy restaurant. The cooks, the ovens and the tables are all there, but someone has to decide which order is cooked first, which table gets which dish and who is allowed into the kitchen. The OS does that job for your device. Your apps are like the customers: they ask for things, and the OS decides how and when they get them.

What it actually does

• Runs your apps. It starts programs, shares the processor between them and closes them when you are finished.
• Manages memory. It gives each app its own space so one app cannot read or damage another app's work.
• Looks after files. It organises storage into files and folders so you can find, copy and delete things.
• Talks to hardware. Printers, cameras, speakers and Wi-Fi all work through the OS, using small programs called drivers.
• Controls access. It handles your account, your password or fingerprint, and what each app is allowed to touch, such as your camera or location.
• Provides the screen you see. The desktop, home screen, menus and settings are all part of it.

The ones you will meet

Many gadgets you would not call a computer also have an OS inside: smart TVs, routers, cars and even some fridges. They are just hidden behind a simpler screen.

Why updates matter so much

Because the OS controls everything, a flaw in it can affect everything. Criminals look for these flaws, and makers fix them with updates. When you delay an update, you leave a known gap open. Most updates also bring bug fixes and sometimes new features.

Every OS version is supported for a limited time. When support ends, the maker stops sending security fixes, even if the device still works perfectly. A device on an unsupported OS is like a house whose locks are never repaired again. If your device can no longer update, plan to replace it or move important tasks such as banking to a supported one.

Tip: Turn on automatic updates, and restart your device when it asks. Many fixes only take effect after a restart.

Try this

1. On Windows, open Settings, then System, then About to see your version.
2. On a phone, open Settings and look for About phone or General, then About.
3. Then check the update page and install anything waiting.

Want the technical version? Read our notes on Linux servers and patch management.

Common myths

"Macs and phones cannot get viruses." Every operating system can be attacked. Some are targeted less often than others, but all of them receive security updates for a reason, and scams that trick you into handing over a password work on any device.

"Updates slow my device down." Occasionally a big update makes an old device feel slower for a day or two while it reorganises itself in the background. Over time, skipping updates is far riskier than the small chance of a slowdown, and many updates actually improve battery life and speed.

"I need to buy a new computer to change operating system." Not always. Many older laptops can run a lightweight version of Linux, or ChromeOS Flex, which keeps them useful and supported for basic tasks such as browsing and email. Back up first and ask someone experienced to help if you have not done it before.