Спереводом! what is a computer? a computer is a machine that performs tasks, such as calculations or electronic communication, under the control of a set of instructions called a program. programs usually reside within a computer and arc retrieved and processed by the computer's electronics. i he program results are stored and routed to output devices, such as video display monitors or printers. a wide variety of activities is performed by computers reliably, accurately, and quickly. computers are extremely versatile. in fact, they are universal information processing machines. according to the church-taring thesis, computer with a certain minimum threshold capability is in principal capable of performing the tasks of any other computer therefore, computers with capabilities ranging from those of a personal digital assistant to a supercomputer may all perform the same tasks, as long as the time and memory capacity are not considerations. therefore, the same computer designs may be adapted for tasks ranging from processing company payrolls to controlling unmanned spaceflights. due to technological advancement, modern electronic computers are exponentially more capable than those of preceding generations. i he physical computer and its components are known as hardware. computer hardware includes the memory that stores data and program instructions: the central processing unit (cpu) that carries out program instructions; the input devices, such as a keyboard or a mouse, that allow the user to communicate with the computer; the output devices, such as printers and video display monitors, that enable the computer to present information to the user: and buses (hardware lines or wires) that connect these and other computer components. the programs that run on the computer arc called software. software is generally designed to perform a particular type of task for example, to write a letter, to display and modify a photograph, or to direct the general operation of the computer.