Computer
From Simple English Wikipedia, the free encyclopedia
A computer is a machine that stores knowledge in its memory, and does automated calculations on that knowledge. Automated calculation means that if the machine is given some input, it will produce some output. People can use computers to do jobs, or just to have fun.
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[edit] Different kinds of computers
Many people think of a computer either as a personal computer, or as a big thing standing around in some special building. Those big computers are usually called Mainframes. But there are many types of computer. An embedded computer is a computer that works out information for other things. For example, mobile phones, Automatic Teller Machines, Microwave ovens, CD Players and Cars all have small embedded computers that help them to work.
[edit] What computers are good at
Computers can be used for many things. Generally, they are good at the following kind of tasks:
- Tasks that repeat themselves very often, or are very boring to do for humans
- searching for some data (in a collection)
- sorting data, by some methods (different ones exist)
- storing large amounts of data (in a database). The computer is then able to find similarities. This is called Data mining.
[edit] How computers store things
The knowledge is stored as symbols, called data. They change symbols and the jobs they have to do into math equations, and can learn the answers to billions of these equations every second. This lets a computer take very hard tasks or strange ideas, and show them with pictures, sound, and words to communicate with the person using them (the "user"). Most of the time, a computer communicates with the user by drawing pictures or writing words on its monitor (screen).
After the computer is done with the data in its memory, it will store it on a hard disk. Most computers have a list of orders that tell the computer how to work with the user. This list of orders is called an algorithm. An operating system tells the computer how to understand what jobs it has to do, how to do these jobs, and how to tell people the results. The disk that contains the operating system is called a boot device.
The different jobs that the computer does are called computer programs. This lets most computers have the same operating system, or list of orders to tell it how to talk to the user, while each computer can have its own computer programs or list of jobs to do what its user needs. Having different programs and operating systems makes it easy to learn how to use computers for new things. When a user needs to use a computer for something different, the user learns how to use one new program.
[edit] Computers and the Internet
One of the most important jobs that computers do for people is helping with communication. Communication is how people share information. Computers have helped people move forward in science, medicine, business, and learning, because they let experts from anywhere the world work with each other and share information. They also let other people communicate with each other, do their jobs almost anywhere, learn about almost anything, or share their opinions with each other. The Internet is the thing that lets people communicate between their computers.
Some people say they like computers and the Internet because everyone can have a voice and be heard by whomever wants to listen to what they have to say.
Blogs are used by many people to say what they want on the Internet. Some people spend most of their time reading and writing blogs. Many people from all over the world use them. Some people use them to write about things that happen to them. Experts can use them to help people learn more. Some blogs are used by companies to sell things.
[edit] Computers and Waste
A computer is now almost always an electronic device. It usually contains materials that will become toxic waste when disposed of. When a new computer is bought in some places, laws require that the cost of its waste management must also be paid for. This is called product stewardship.
In some countries, old computers are recycled (melted down) to get gold and other metals from them. This is dangerous, because this procedure releases the toxic waste into the water and soil.
Computers become obsolete quickly. Very often, they are given away, and new ones replace them within two or three years. This makes the problem worse, so computer recycling happens a lot. Many projects try to send working computers to developing nations so they can be re-used and will not become waste as quickly.
Computer recycling has been seen as a bad idea in the last few years because some still had information on them. This could lead to fraud or identity theft by criminals.
[edit] The Main Hardware in a Computer
Computers come different forms, but most of them have a common architecture.
- All computers have a CPU
- All computers have some kind of data bus which lets them get inputs or output things to the environment.
- All computers have some form of memory. These are usually chips (integrated circuits) which can hold information.
- Many computers have some kind of sensors, which lets them get input from their environment.
- Many computers have some kind of display device, which lets them show output. They may also have other peripheral devices connected.
A computer has several main parts. The brain is the CPU which sits on top of the motherboard, which could be called the nervous system. The motherboard is connected to the power supply(which includes the fan for cooling), the CD drive, the hard drive, the floppy drive and, on older computers, the ZIP drive. The motherboard is also connected to the graphics card which sometimes is built into the motherboard. Some computers have sound cards in addition to the graphics card and these connect directly into the motherboard also. USB and Firewire ports also connect directly to the motherboard along with all other external ports.
