Basic of computer

 Basic of Computer -

  1. What is Computer ?

      A Computer is a machine or device that performs processes, calculations and operations
       based on  instructions provided by a software or hardware program. It is designed to
       execute applications and provides a variety of solutions by combining integrated
       hardware and  software components.

                                      or

   A  Computer is a machine or device that accepts information and manipulates it for some
      result based on a program, software, or sequence of instructions on how the data is to be                      processed.

   2. Types of computer :

       There are four types of computer :-

1. Super Computer
2. Mainframe Computer
3. Mini Computer
4. Micro Computer       

  3. Full form of Computer : Common Operating Machine Purposely Used for                 Technological and Educational Research.

  4. Computer Organisation : 

       The block diagram of  computer is shown below (fig-1.1).

Block diagram of  computer organisation

    The computer performs basically five major operations of functions irrespective of their size and make.

These are :

1. It accepts data or instruction by way of input
2. It stores data 
3. It can process data as required by the user
4. It gives results in the form of output
5. It controls all operations inside a computer

      Discuss below each of these operation

1.  Input : This is the process of entering data and programs into the computer system.                   
2. Control Unit(CU) : The process of input , output ,processing and storage is performed under   the supervision of a unit called 'Control Unit' .It decides when to stop it, where to store data, etc. It takes care of step -by-step processing of all operations inside the computer.                       
3. Memory Unit : Computer is used to store data and instructions.                                                   
4.  Arithmetic Logic Unit (ALU) : The major operation performed by the ALU are  addition ,     subtraction, multiplication, division, logic  and comparison .                                                        
5.  Output :  This is the process of producing results from the data for getting useful information.                                                                                                                                                                                                       

 The ALU and the CU of a computer system are jointly known as the central processing  unit (CPU).    You may call CPU as the brain of any  computer system.                                                                             

5. Peripheral devices :
      Peripheral devices(fig-5.1) are connected to the computer externally. These devices are used for                      performing some specific functions.Peripheral devices are as follows:

1. Input    
2. Output devices
3. Others Peripherals                                                                                            

     

        Fig- 5.1 : CPU and  the Peripheral devices 

  4.1 INPUT DEVICES :

         Input devices accept data and instructions from the user. Following are the examples of                  various input devices, which are connected to the computer for this purpose.

1. Keyboard 
2. Mouse
3. Light pen
4. Optical/magnetic Scanner
5. Touch Screen
6. Microphone for voice as input
7. Track Ball 

4.2 OUTPUT DEVICES : 

      Output device receives information from the CPU and presents it to the user in the desired from. The processed data, store in the memory of the computer is sent to the output unit, which then converts it into a form that can be understood by the user. The output is usually produced in one of the two ways – on the display device, or on paper .

  

1. Monitor
2. Printer  
3. Plotter
4. Facsimile (FAX)
5. Sound Card and Speaker(s)                                                                                                                                                                                                                                                                                                                                                                                                                             6. COMPUTER SOFTWARE  :

                         As you are aware, computer cannot do anything on its own. It is the user 

                 who instructs computer; what to do, how to do and when to do. In order to 

                 perform any task, you have to give a set of instructions in a particular sequence 

                 to the computer. These sets of instructions are called Programs. Software refers  

                 to a set of programs that makes the hardware perform a particular set of tasks in 

                 particular order. 

                 Software can be classified mainly into following categories and sub-categories are :

            

                  1. System Software :  further classification as :-

                       * Operating System 

                       * Utilities

                  2. Application  Software : further classification as:-

                       * Generalized package

                       * Customized package

       

       7. Computer Languages :

               Languages are a means of communication. Normally people interact with

             each other through a language. On the same pattern, communication with computers

            is carried out through a language. This language is understood both by user and the 

            machine. Just as every language like English, Hindi has its grammatical rules;

                  

                            Every computer language is bound by rules known as SYNTAX of that 

           language.The user is bound by that syntax while communicating with the computer 

           system.

   

           Computer languages are broadly classified as : 

1. Low level Language                                                                                                                     
2.  High level Language