Why do we always need a computer

Smartphone and other computers

This chapter as a listening offer

When you hear the word computer, many people think of a personal computer.
PC is short for personal computer.

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Personal computer

The term "personal computer" comes from the English language.
It means "personal computer" in German.
The term was invented in the 1970s.
Back then, only technicians could operate a computer.
You can also operate the personal computer yourself at home.
Personal computers are computers for personal use.

Smartphones, tablets and laptops are also personal computers.

But there are many other computers that are not PCs.
More about that later.
First we explain what a computer is made of and what a computer needs.
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Hardware - anything you can touch.


The processor is part of the hardware.

Processor is the name of the component that controls the computer.
The mouse and keyboard are also part of the hardware.
The hard disk and the screen are also part of the hardware.
The hard drive stores the information in the computer.
Many computers have a hard drive built into them.
You can also save data elsewhere, for example on a USB stick.

Software - tells the computer what to do

Hardware alone does not work.
Hardware needs software.
Software are that Programs in the computer.


Programs consist of instructions that solve problems or work on tasks.
For example, there are programs that can be used to write texts.
Games on the computer are programs too.
The operating system is the most important program of the computer.
The operating system makes the computer work.
For example, it ensures that a text file is forwarded to the printer.

Computers need a language

In order for the computer to understand instructions and be able to remember things, it needs a language. When people want to write something down in their language, they use words with lots of letters.


That's enough to save everything.
For the computer is
the big letter A = 01000001
and the small letter a = 01100001.

Maybe it sounds complicated at first, using so many numbers for a single letter. But it's easy for the computer.
For the computer, a color consists of many zeros and ones.
The computer stores an image as many zeros and ones. The computer screen turns it into colors and shows the picture.
The computer language is also called binary code.

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How do you recognize a computer?

All computers have two things in common: they use computer language and they have one processor. The processor is part of the computer hardware. The processor controls processes in the computer.
Process means:
Something is done according to the steps in a guide.


This picture shows the inside of a computer with the processor. (& copy picture-alliance, PIXSELL)


An example:
There is also a computer with a processor in a washing machine.
The processor controls the washing machine.
You press a button on the washing machine and give an order.
The processor then works through a manual.

The processor addresses the individual parts in the washing machine directly:
  • The processor gives the command: "Lock the door".
  • He gives the command to the valve for the water:
    "Let water run into the machine".
The processor issues different commands until the washing program is over.

What is data

Computers use data. Data consist of signs.
For example, let's take the sequence 12041994:
You don't yet know what this number is supposed to mean. You don't get any information from the number. You still need explanations.
This is the only way you can tell what the number 12041994 is supposed to mean.

The number 12041994 means nothing to you without explanation.
But maybe you know that it is Marie's date of birth.
Then you can read the numbers and get information from them.
It works even better when the numbers are written down like this: 04/12/1994
Because that's an agreement on how to write a date.

You can then obtain information from the data "12041994" and the declarations "Marie" and "Birthday".
You will then know: Marie's birthday is April 12th, 1994. Marie's birthday is in spring.

Explanations about data are called Metadata.

No information can be obtained from data alone. Data can become information if you know what it is supposed to mean.
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When a computer extracts information from data and metadata, it is called Data processing.
Computers are particularly good at data processing. For example, you work faster than humans.


Or they can pass data on to other computers.
Everything that is stored or processed on a computer is also called data. The hard drive of a computer is therefore also called Disk.

A text is saved as a text file. The computer also saves data in the text file that provides information on how the text was created.
For example, it stores:
  • when a text was saved,
  • who wrote a text
  • or when a file was last changed.
A special type of data is data about people. Such data is called personal data.

For example:
  • name and adress
  • height and weight

What else are there for computers?

Computers are not just PCs.
Computers are also built into many devices.
You don't always see the computers in the devices.
For example:
  • in the refrigerator
  • in the car
  • in the washing machine
  • in the MP3 player
  • on TV
  • in the ATM
  • in the elevator
  • in the traffic light
One can say:
We are surrounded by computers.
Computers look very different and are of different sizes.
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Computers exchange ideas

Computers can also exchange ideas. They use the language of the computer for this.
Data can be, for example, text, images, sounds or contact information.

For example, computers exchange information about this Internet with each other.

Computers are connected to each other across the world through the Internet.
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What are algorithms?

People need instructions so that they know how something is made, for example a recipe for cooking or instructions for building.

A computer also needs instructions so that the computer knows what to do.
For example, he needs instructions on how to find his way to another city.
The instructions tell the computer what to do in which order.
This is how the computer finds the best way.
Such instructions are also called algorithm.
Algorithms are created by humans.

for example to sort something.
One can therefore also say:
Algorithms are instructions on what to do when.

In everyday life you can write instructions for many tasks:
  • for recipes,
  • when assembling a piece of furniture
  • or when operating a device.
Instructions for eating muesli can look like this:
  1. Get an empty bowl.
  2. Fill in cereal.
  3. Fill in milk.
  4. Eat your cereal with a spoon.
  5. Stop eating when the bowl is empty.
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Instructions must observe certain things:
  1. The order of the individual steps:
    What do you have to do first?
    Then what do you have to do?

  2. How often do you have to do it?
    When can you stop?
The instructions must come to an end.

People can change the order of instructions.
  1. You fill in the milk first and then the cereal.
  2. Or you stop eating when you are full.