FUNCTIONAL UNITS OF A COMPUTER

Functional Units of a Computer 

         The hardware of the computer system is collection of electronic circuit and other devices.  There are certain basic components  or building blocks that exist in all computer systems.  These components are the central processing unit (cpu),  Memory,  Input device and the Output device.  A systematic interaction between these components is essential for the functioning of computer 

1. Central Processing Unit (CPU) 

 

            The CPU  is referred to as the brain of the computer.  The CPU controls the overall functioning of system. It is the part of the computer  where the actual processing  of data takes place.  The CPU controls the flow of data by taking input from the input device,  storing data in memory and retrieving them when needed and directing the pricessed data to the output device. The CPU comprises three parts ALU, Control unit and Memory. 

 2.  Arithmetic Logic  Unit  (ALU) 

        The ALU performs all the arithmetic calculations and takes logical decisions.  The data stored in the memory are sent to the ALU where the operation takes place and the result is sent back to the memory.  The results of a logical operation is either TRUE or FALSE. These operations provide the capability of decision making to the computer. 

 3. Memory  

         Memory is used for storage of data. The data from the input devices or mass storage devices are sent to the memory for storage.  The intermediate and final results of processing are also stored in the memory.  The data stored in the memory can be retrieved when required at any time.

 4. Control  Unit  

            The control unit control coordinates the functions of all other units of a computer system.  It controls the working of other components by sending control signal until a required operation is done properly.  The control unit performs the following functions.

1.   Regulate data flow between input       devices,  ALU,  memory and output       devices. 

2.   Sequence the execution of a program   i.e. carrying out all the instructions of a     program one by one with the help ALU   and  memory 

3.   Decoding and interpretation of     instructions. 

 5. Input  Unit  

       The input devices are used to enter data to computer system.  There are many types of input devices depending on the nature of data to be entered.  Keyboard is one of the most commonly used input device. It used for alphanumeric data entry. Mouse is another common input device used to locate screen positions. The input device is also responsible for translation of data to a form that the computer system can understand. 

 6. Output  Unit  

          Output device is used to communicate the information to the user. The output devices translate the processed data in machine readable form to a form that can be interpreted by humans. The most common types of output devices are monitor,  which resembles the television screen and printer,  which prints copy from the computer onto paper.  Outputs can also be obtained in the form of drawngs and voices.

    

Various type printers