About computer

A computer is a machine which stores knowledge in its memory and does calculations on that knowledge. This knowledge is stored in symbols; it is called data. A computer usually has a monitor to show results. However, some computers can speak; these computers can be used for voice mail.
A computer frequently requires a boot device. The boot device contains the computer's operating system and data. Computer programs can be installed onto a computer. Some people think that computers are less useful if they do not have access to the Internet. They think this because the Internet allows the computers to send and receive data and email across the world.
A computer is now almost always an electronic device. It usually contains materials which are toxic; these materials will become toxic waste when disposed of. When a new computer is purchased 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. Computer recycling is thus common. Many projects try to send working computers to developing nations so they can be re-used and will not become waste as quickly.