Wikijunior:How Things Work/Computer

What does it do?
Computers are designed to do things that require very fast and accurate mathematical ability and memory, but no creativity. Computers can be used to remember information like books or songs, and they can be used to add thousands of numbers per second.

They have lots of different components: there are places to store information and a place to do calculations with that information. These calculations are how computers do everything they do. They also need ways of getting input from you, like a keyboard or touchscreen, or even a camera. They have ways of telling you things, which is why you need screens and speakers.

One of the most important things they do is talk to other computers. That's how the Internet works; it's just your computer talking to other computers, asking them for web pages, and showing them to you.

Who invented it?
The computer was not invented by any one person, but is rather an evolution of many devices. A German scholar, Wilhelm Schickard, was the first to create a calculator, which is a type of simple computer. However, the first computer that could be taught to do new things, or programmed, was created by Konrad Zuse more than three centuries later. The first personal computer, like the ones that sit on desks, was created by the Computer Terminal Corporation with the Datapoint 2200.

Although modern computers are created by many different companies, their operating systems are generally either Microsoft's Windows, developed under Bill Gates, or Apple's macOS, developed under Steve Jobs (1955–2011). Some computers use the Linux operating system, which is developed in public, often by volunteers. Mobile phones are computers too and they need operating systems. These include Android (a type of Linux system) and iOS (which is like macOS).

How does it get power?
Computers draw their power from an electrical source, like a plug or a battery.

How does it work?
Modern computers work by taking input, processing it, and returning it as output, millions of times per second.

Where does it get its input?
Different types of input come from different places. The keyboard10 sends letters and numbers to the computer, a mouse9 sends information on what to do with the cursor, and a microphone sends sounds. Although you don't control it directly, the internet can also send input. Even though all this information is different, it is all transmitted in the same language that all computers use, binary, which is just a series of ones and zeros.

How does it process this input?
All the input in the computer is sent to the central processing unit, or CPU3. The binary ones and zeros, or data, go through millions of tiny gates, each of which takes some inputs and returns an output.The CPU's gates also get data from the hard drive or solid state drive8 of the computer, which remembers information, the CD drive7, which is where you put disks for the computer to read, and other parts of the computer. Once the gates have processed all the data, the results are sent from the processor. Some of the results go to the outputs, while others go inside the computer to tell all the other parts of the computer what to do, like telling the hard drive or solid state drive to remember something.

What happens to the output?
The outputs of the computer are connected to external devices. The most important device is the screen1. The screen takes its inputs from the computer and understands the data as a picture. The screen then displays the picture on the screen. Another output device is the speakers. They take output from the computer and change it into sound. There is also output that you can't see or hear - for example when the computer sends data to the internet to ask for a web page.

How does it vary?
Computers are created by many different companies. However, almost all CPUs are created by either Intel or AMD, which are both companies. The operating system can be different as well, although the three leading operating systems are Windows, macOS, and Linux. Windows is the most common operating system in people's normal computers. macOS is also very common. You might not have heard of Linux; although you can use it at home, it's more often found in special computers like the ones that make websites work, rather than in laptops.

Different computers have different parts on the inside. Some have better hard drives or solid state drives so they remember more, or better processors so they work faster. Over the years computer hardware has got better and better. Processors are able to do more calculations in every second than they used to, and hard drives can store more information in the same space. This means that you can do things today with a cheap computer that would have been very difficult and expensive a decade ago.

How has it changed the world?
Computers have completely changed the way we solve problems and get things done.

By building up complex software programmes, individuals and groups of people can process information quicker. Scientists are using computer models to test new medicines and study chemical reactions in ways they never could do before.

Computers today are used to manipulate pictures and videos. Sophisticated animations can be constructed on computers, and this kind of animation is increasingly being used in television and films. Music is often recorded using sophisticated computers to process and mix sounds together.

Business and governments use computers for a wide variety of things: books are written, typeset and produced on computers, put into boxes and shipped by machines controlled by computers. The vans which ship those books to bookshops are tracked using computers tied into satellite navigation and tracking systems. When you buy a book in a shop, the till used to take your money is a computer that is often tied into stock control systems. Information from all of those shops can be pulled together to produce reports for businesses and delivered by e-mail. The business may then pay their taxes electronically, and the government manages the services paid for with those taxes using more computer systems.

The role of computers in society is shown whenever there is some kind of panic about computers like the "Y2K problem". When programmers were designing computers in the 1960s and 70s, they never thought that those systems would be used for a long time, so stored the year as two digits: "70" rather than "1970". When the year 2000 came around, a lot of time and money was spent fixing this problem. Many predicted that society would break down because of the problems that were caused by computers failing. Thankfully, this did not happen, but it shows just how important computers are to our everyday lives.

What ideas and/or inventions had to be developed before it could be created?

 * The transistor, an electronic switch that can be in two positions - either on {1} or off {0}
 * Integrated Circuits(IC) which consist of several logic gates