computer A computer is a machine (mostly electronic) that is able to take information ( input ), and process it to make new information ( output ). Computers have existed for much of human history . Examples of early computers are the astrolabe and the abacus . There are four main processing steps in a computer, and they are: inputting , storage , outputting and processing. Modern computers are very different from early computers. They can do billions of calculations per second. Most people have used a personal computer in their home or at work. Computers do many different jobs where automation is useful. Some examples are controlling traffic lights , vehicle computers, security systems, washing machines and digital televisions. A computer user can control it by a user interface . Input devices include keyboard , mouse , bu...