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PROCESSING DEVICE

            The device which is used to process the input data is called a processing device. In

            a computer  system,  the  Central  Processing  Unit  (CPU) works as a processing
            device. It controls the entire working of the computer system.

            The parts of the CPU are:

               Arithmetic Logic Unit (ALU): It performs all the arithmetic

                operations such as addition, subtraction, multiplication,
                division and all the logical operations such as greater
                than, less than, equal to, etc.                                         CPU Box           CPU

               Control Unit (CU): It controls the working of all the parts of a computer.

                It acts like a supervisor and is used to control the flow of information from
                the CPU to other parts of the computer and vice-versa. The CU gets data
                and instructions from the memory unit and passes them on to the ALU in a

                step-by-step manner.
               Memory Unit (MU): It stores the instructions given by the input devices before

                they are sent for processing. It also stores the result or the output before it is
                sent to the user.


                                                  Central Processing Unit

                                                   Arithmetic Logic Unit

                    Input Devices                      Control Unit                     Output Devices


                                                       Memory Unit



                                     1.   Which device is known as the brain of a computer?
                    uiz   Bee            ______________________________________________

                                     2.   What is the use of a keyboard?
                                         ______________________________________________




            OUTPUT DEVICES


            The devices that display the results of processing done by the CPU are called
            output devices. Output can be a printout from the printer, sound from the
            speakers, image on the monitor or content on the projector. The most commonly

            used output devices are printer, monitor, speakers, projector, plotter, etc.



                                                                                       Hardware and Software  11
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