2nd Class Computers Science Processing Devices Processing Devices          

      Processing Devices

Just like people follow recipes to make food taste in the same way the CPU uses programs to know what it needs to do. The CPU is the 'brain' of the computer. It is the CPU that understands and executes all our instructions which can either be input/output operations or numerical calculations or logical comparisons. It also coordinates the functions of other units of the computer and ensures that everything functions smoothly.  The CPU has to handle a lot of tasks - Read this. Write that. Display that. Copy that........all at the same time. Therefore, the CPU has got some helping parts. The CPU is made up of three parts, namely the Memory, the ALU (Arithmetic and Logic Unit) and the CU (Control Unit). In smaller micro computers like the PC) (Personal Computer, the ALU and the Control Unit are together and this unit is called the Microprocessor. We will now look into the processing of the computer in detail. (See Figure 2.4.10)

Imagine that you are a CPU. You would follow this program if you were thirsty.    

Similar to the program shown above, the CPU inside the computer also performs a series of steps to carry out its tasks with the assistance of its helping parts.  

     Memory  

This part stores the data and information, A computer has memory to store data and information for future use. The Memory is the computer's work area. This is the place where the data and programs get stored before being processed and the place where the results get stored before being sent as output.  

     Control Unit

This part controls all the operations of the computer. The Control Unit interprets the results stored in memory, fetches the data for the next instruction from the memory, and coordinates the activities of ALU, the memory and other devices.  

     ALU

This part performs all the arithmetic and logical operations on data selected from the memory. It performs addition, subtraction, multiplication, division and logical comparisons (such as X>Y) on the data sent to it from memory.

Interaction among the different components of the computer.

 ALU performs all the arithmetic and logical operations on data selected from the memory. What does ALU stand for?

(A) Arithmetic and letter unit                    

(B) Arithmetic and logical unit

(C) Arithmetic and line unit                         

(D) Asynchronous and logical unit  

Answer: (B)                

Explanation

Correct Option:

(B) ALU stands for Arithmetic and Logical Unit. Therefore, option (B) is correct.

Incorrect Options:

(A) Option (A) is incorrect.

(C) Option (C) is incorrect.

(D) Option (D) is incorrect.    

 CPU performs many functions simultaneously. Which part of the CPU processes the logical functions?

(A) Control Unit                                               

(B) ALU

(C) Reasoning unit                                          

(D) All of these  

Answer: (b)

Explanation

Correct Option:

(B) All logical functions are performed by the ALU.

Incorrect Options:

(A) Option (A) is incorrect.

(C) Option (C) is incorrect.

(D) Option (D) is incorrect.