The Operating System: Who Shares Out the Work
You listen to music, type a message and something is downloading. There is only one processor, yet everything seems to run at once. Who arranges that? Today you become the dispatcher.
For parents: a one-page guide — dinner questions and a game without a screen.
01Remember
Before we start, recall three things from earlier lessons. Think first, then open the answer.
What is the processor's job?
It carries out instructions very fast, step by step. It does not think or feel — it follows steps.
What is the difference between working memory (RAM) and storage?
Working memory is like a desk you work on — it forgets when the power is off. Storage is like a cupboard — it keeps things even without power.
Can you read a book and eat an apple at exactly the same moment?
Not quite — you switch quickly: a bite, a page, a bite. Remember this answer, you will need it.
02Story
The first computers were very expensive and slow. Often they did just one job, and some programs ran for hours.
In the 1960s people found a way for many users to share one computer. It gave each task a small slice of its time and switched between them so fast that everybody felt the computer was working just for them. This is called time-sharing.
The one who shares out the time is the operating system (OS). Today it is in phones, tablets and game consoles too. For example, Windows, macOS, Linux, Android and iOS are operating systems.
03Worked example
You listen to music, type a message and a file is downloading. Here is what the operating system does:
It knows the parts
The operating system manages the parts of the computer — processor, memory, screen, sound — and tells them when to work. It is the go-between for programs and hardware.
It gives each task some time
The music, the message and the download share the processor's time. Putting tasks in order is called scheduling.
It judges what matters more
If the mouse pointer freezes, you notice at once. So it gets a higher priority than the download, which can wait.
It switches fast
It switches tasks so fast that you do not notice. Modern processors usually have several cores, and some tasks really do run at the same time. Even then, the operating system decides which one runs where.
04Try it now
In this lesson there is only one processor and four tasks. Time is counted in “ticks” — small equal slices. Each cell is one tick. This is simplified — real computers are more complex.
1 · Predict
A long task (“Downloading a file”, 4 ticks) is first in the queue. You move the mouse. What happens if the computer works “first come, first served”?
2 · Run: the dispatcher sorts
Choose how the dispatcher orders the tasks. The coloured cells show which task is on the processor in each tick.
3 · Change: set the priority
Press the button next to a task to change its priority: low → medium → high. Then run “By priority”. Can you order things so that the mouse and the music do not wait, and the download finishes last?
Note: when two tasks have the same priority, the one higher in the list goes first.
05No screen: “Dispatcher in the Room”
You need: 5 slips of paper, a pen, 10 buttons (or other small things) and one or two more people. Play on a clear floor where you can walk. Do not run. The tasks are pretend — nobody touches anything dangerous.
On four slips write pretend tasks and how many steps each has. For example: “Set the table — 3 steps”, “Line up the shoes — 2 steps”, “Water a flower — 1 step”, “Stack the books — 4 steps”. Put as many buttons next to each as it has steps.
You are the dispatcher and another person is the processor. The processor can do only one step per turn: takes a button and says “done”.
The dispatcher decides whose turn it is. Try three ways: 1) in order, until a task is finished; 2) the shortest first; 3) one step from each task in a circle.
Count how many turns each task waited before it started. Which order makes the most urgent one wait the least?
06Make your own
Invent four tasks of your own, for a computer or for your day.
- Write them on slips: a name, how many steps it takes and how important it is (low, medium, high).
- Before you play, predict: which task finishes first with “first come, first served”? And with “by priority”?
- Play “Dispatcher in the Room” with your cards and check your prediction. If you were wrong, find out why.
07What I learned
- The operating system manages the parts of a computer and shares out the work among programs.
- One processor does one task at a time. The operating system switches so fast that it looks as if they all run at once.
- Order matters: if the long task goes first, the others wait. Priority helps the most urgent task not to wait.
A computer decides what goes first. How do you choose what to start with today?
Check yourself
1. The operating system is…
2. Why do several programs seem to run at once when there is one processor?
3. Which of these is an operating system?
It is yours when you can explain to someone why the order of tasks matters and how priority helps. No points and no rankings — just a skill.
08I have a question
Do you still have a question? Write it here. It goes to your parent, not to strangers. Your parent confirms their e-mail first.
The form is loading… If it does not appear, write your question on paper and show it to a parent or teacher.
·Sources
- Title: The Operating System: Who Shares Out the Work (DB-VK-11) · Author: Children's Library, East Accelerator Foundation · Source: original content, 2026 · Rights: CC BY-SA 4.0.
- Facts were checked (retold in our own words, nothing copied) against Wikipedia: “Operating system”, “Time-sharing”, “Scheduling (computing)”, “Multi-core processor” (viewed 2 October 2026).
- Licence: CC BY-SA 4.0 · Children's Library, East Accelerator Foundation, 2026. You may share and adapt this lesson if you credit the author and keep the same licence. Learning is free forever.