Page 61 - AI Ver 1.0 Class 9
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Characteristics of a Computer
            Following are some of the important characteristics of a computer:
               • Speed: A computer can process data at a speed of millions of instructions per second. It is faster than human
              beings in doing complex tasks which can otherwise take a few days to process manually. It uses its internal clock
              to measure the processing speed for completing the job. The unit of computer speed is Hertz = one cycle per
              second.
               • Accuracy: The information provided by the computer is very accurate. Sometimes we may feel that we are
              not getting the desired result or maybe the output generated is not accurate. When we give wrong input to
              the computer, the system malfunctions or gives wrong output. It works on the principle of GIGO(Garbage In
              Garbage Out).
               • Reliability: Information received using a computer is highly reliable. During an online flight reservation, seat
              allocated to one person cannot be reallocated to another at any cost. So, we can totally depend on the availability
              of information of seats during online booking or availability of stock during online shopping.
               • Storage: Large volumes of data can be easily stored in a small space. Data can be preserved for a long time with
              least possibility of data tamper or data loss. There is no need to maintain a huge volume of manual registers and
              separate store room allocation to it.
               • Versatile: Computer doesn’t mean a laptop or a personal computer. It can be a smartphone, tablet, online
              booking counter machine, ATM machine, X-ray machine in hospitals and GPS system in our cars. It is available in
              a variety of forms. So, we can say that it is highly versatile and has been designed to do any kind of job.


                    Input Devices


            The devices which help to give data or instructions to the computer are called input devices. The most commonly
            used are keyboard and mouse. Let us learn about some of the input devices.



            Keyboard
            A keyboard is probably the mostly used input device which can be either
            wired or  wireless. It is used to accept  textual  data  from the  user.  It is
            impossible to imagine a computer without one. A typical keyboard has a
            typing area that includes the letters of the alphabet, numbers, punctuation
            marks, and other basic keys similar to that of a type writer.                      Keyboard


                                 Mouse
                                 A mouse is another input device which is also known as a Pointing Device. As you move the
                                 mouse, the pointer on the screen moves. A typical mouse has two buttons and a wheel. It
                                 can be either wired or wireless.
                 Mouse



            Scanner
            A scanner is a device used to read the hand written notes, images, photos and transfer
            it in a digital form onto the computer where it can later be saved or manipulated as per
            the requirement.
                                                                                                     Scanner







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