GoalFollow what happens inside a computer when I type, and explain why I should save my work.
New words
save · to keep your work so you can open it again laterstep · one small part of a job, done before the next partdiagram · a drawing with arrows that shows how something works
Explanation
What happens in the moment you type a letter? Five steps follow one another. First, you press a key in the word processor. Second, the program passes the letter to the operating system. Third, the operating system sends the data to the CPU. Fourth, the CPU processes it and sends the answer back to the operating system. Fifth, the operating system hands it to the program, and the letter appears on the screen. All this takes a tiny fraction of a second. If something goes wrong before you save, your work can be lost. So save often, the way you put a finished page into your folder.
1 Press a key→2 Program passes the letter→3 Operating system sends it to the CPU→4 CPU processes it and sends it back→5 The letter appears on the screen
Worked examples
Yasmin types the letter “a”. Step 1: she presses the key. Step 5: the “a” shows on the screen. Steps 2, 3 and 4 happen inside, where she cannot see them.
Omar plays a game. The same idea works: his button press (you) goes to the game, the operating system and the CPU, and the new picture comes back to the screen.
Jana wrote a long story but the computer switched off before she saved. The story was lost. Now she saves after every page, like putting each page in a folder.
Class activity
Pass the letter. Five children stand in a line: You, Program, Operating system, CPU, Screen. You whisper a secret letter to the Program, who passes it on, step by step. The CPU “processes” it by saying it twice, and the Screen writes it on the board. Does the same letter arrive? Then talk about why saving matters.
Practice
1
In the five steps, what is step 3?
The operating system sends the data to the CPU.
2
Which part shows the letter on the screen at the end?
The program, after the operating system gives it the result.
3
Why should you save your work often?
If something goes wrong, saved work is not lost.
4
Draw the relation for playing a game: you, game, operating system, CPU. Which comes second?
