2nd Class Computers Science Computer Processing Working Principle of a Computer

         Working Principle of a Computer

If you had watched a magic show then you would have seen that the magician puts some colored bits of paper inside his hat, mumbles some magic words and then pulls out a rabbit! And you begin to wonder because what went in did not come out. The computer can perform some magic too. For example, it can add large numbers and make other complex calculations and give you the result in just a few (seconds. Thus many actions of computer appear as magic.

Just as a human being can be seen as a combination of body and mind, the same toes for a computer. The computer is a two part system consisting of a body and wind. The body of the computer is the hardware such as CPU, VDU, etc. These are the mechanical and electronic parts which can be seen and touched. The mind of the computer is the software. It consists of commands and instructions. Therefore a computer is a collection of electronic parts (body) with a set of instructions controlling it (mind).

Almost all the systems and the machines that we find around us work in the same ray. They accept some Input. These inputs are processed in a specific manner to produce some Output. For example, we take oranges, put them in the juicer, switch I on and finally we get orange juice.  

This Input-Process-Output (I-P-O) cycle is represented in the following figure:    

     I-P-O Cycle

The I-P-O (Input-Process-Output) cycle can be illustrated with the help of an example of adding numbers. Suppose you are asked to add two numbers 40 and 50. When you are told to add these two numbers you perform this addition by the factoring processes: (See Figure 2.3.1)

• First, you hear the two numbers.
• Then you store the numbers in your memory.
• Your brain adds the two numbers.
• Then the result (40 + 50 = 90) is stored in your memory.
• You either speak out the result loudly or write it down, depending on what is required.  

Now let's evaluate the entire procedure in the form of Input-Process-Output cycle. The numbers that you have to add are called input. The method of addition is called process and the final result is called output. Here, the inputs are 40 and 50. The output is 90. Your ear is the input device, the brain is the processing unit and mouth is the output device.  

As you know, the computer does not make any mistake. If there are any errors in the result or output, it is mostly because of the human being who is Goring the data. These errors are called Bugs because they can be irritating. Just like real bugs (small insects). The computer follows the GIGO (Garbage In Garbage Out) concept, that is, if we give wrong data or instructions to the computer, then the result will also be wrong. In the case of computers, two kinds of Input are required. One, the basic or raw data and second, a set of instructions needed to process this data. This set of instructions is referred to as program or software.    

     This is explained in the following figure:      

     Processing Information  

To understand the I-P-O cycle of the computer, we will I take the example of an airline reservation system.