What are computer systems?

Computers and digital devices work by storing and process To work with or organise information. information.
Processing means to work with or organise this information in a sensible way.
Computers use a computer processor to do this.

Video: What is computer control?
Join Emma in the workshop to find out more about computer control.
Lots of the electronic devices and machines that we use are controlled by computers.
Not necessarily computers like this, but smaller computers that are built inside them.
Computers don’t think for themselves; they need us to tell them what to do. We need to control them.
To do this, we use computer programmes. But what are computer programmes?
A computer programme is a list of instructions written in a special language, or code.
Code is written using numbers, letters and symbols.
To programme a computer to do a particular job, the code instructions need to be written in the right order, or sequence.
Let’s think about when we wash clothes in this washing machine.
A computer inside this machine controls every step of the washing process.
So, the steps are done correctly and in the right order.
Computer programmers will have written the code for the steps of many different wash types, and placed these in the correct sequences.
This code is stored in the computer’s memory.
All the user needs to do is select what type of wash they want, and press a button to start the machine.
First, the computer makes the machine fill with soapy water.
Then turns and washes the clothes.
Then rinses away the water and soap.
Before finally, the machine spins the clothes around through moves in water.
Water, wash, rinse, spin.
Unlike people, computers can’t tell if something is in the wrong place in a sequence.
They will just carry on running the programme, even if things start to go wrong.
If the washing instructions are in the wrong order; spin, rinse, water, wash, for example,
the washing machine won’t do a very good job.
The clothes will come out all soapy and far too wet.
Lots of electronic devices that we all use every day, use computer control.
Have a look around your house or outside when you’re out and about, and think about which devices might use computer control.
What are input and outputs?

A computer can only process information that is has been given or that it has collected.
This information is known as inputData that is sent to a program to be processed.. It has been put into the computer system.
Some devices that are used to input that information are:
- sensors which collect information from the outside world such as light, moisture, movement and temperature.
- buttons which can be pressed to make something happen.
- remote controls which send signals from a distance.


When the computer has processed the information from the input, it then sends instructions to an outputInformation sent out from a computer device after processing. device to carry them out.
Some output devices include:
- motors which move.
- lights which brighten the darkness or show a signal.
- speakers or buzzers which produce a sound.
The output is the action produced by the output device.

What is computer control?
A computer control system is always made up of an input, a process and an output.
It can be used to take in information from more than one input and produce more than one output.
The output is decided by instructions inside computer programA list of instructions that a computer can understand. which are written in code. The computer processor uses the information in the program to give the right instructions to the output device to make it complete the task.
Let's have a look at some everyday examples where computer control used.
Image caption, In industry
Robotic arms can adapt to different situations on a production line by following a computer program.
Image caption, In hospitals
Scanners in hospitals can use computer control to carry out the movements needed in a scan and then distribute information.
Image caption, In shops
Cash machines and card readers use a computer control system to know if people can take out money and to also move money from the customer to the shop.
Image caption, In the home
Many devices in the home now use computer control, from washing machines, to automatic vacuum cleaners and smart fridges.
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Traffic lights
Computer control can be used to make traffic lights work.
Computer programs tell traffic lights when and how to change at a pedestrian crossing or a junction.
A sensor can detect pedestrians and traffic. Then a timer can decide how long each light should be shown for.
A computer program sets out the sequence the traffic lights follow.
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Key words
Computer program | A computer program is a set of instructions, written in a programming language called code, that tell a computer to perform specific tasks or functions. |
Input | An input is the data, signal, or energy that is provided to a system to start a process. |
Output | An output is the response produced by a system or process after it has received the input. |
Process | To work with or organise information sensibly. Computers use a computer processor to do this. |
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