Who is in charge of your phone?
You tap a game and it opens. You get a message and the screen lights up. Music plays while you scroll.
Something is deciding what runs and when. It is not the game and not the music app. It is a program that runs everything else.
By the end of this lesson
Note
I can describe the main jobs of an operating system (the program that runs a computer).
Key words
| Word | What it means |
|---|---|
| CPU | the part that runs program instructions |
| Operating system | the main program that runs the computer and its other programs |
| Boot | to start a computer and load its operating system |
| Firmware | a small program stored on the board that starts the computer |
| Driver | a small program that lets the system use a device |
| Interface | the way a person uses the computer |
| Directory | a folder that holds files and other folders |
| RAM | fast memory for what is running now |
The cells students fill in are left blank in this preview.
Starter
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Starter
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Booting up
When you press the power button, the firmware wakes first. It checks the main parts.
Then it finds the operating system on the storage and loads it into RAM. This is called booting. When it is done, you see the sign-in screen.
Sharing the CPU and the RAM
Many programs run at the same time. There is one CPU and a limited amount of RAM.
The operating system gives each program a short turn on the CPU, again and again. It is so fast that everything seems to run together.
It also gives each program its own part of RAM, so programs do not overwrite each other.
Check
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Check
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.