Computer Notes Chapter- 6 Anatomy of Computer ! Central Processing Unit ! Arithematic Logic (ALU) ! Control Unit (CU) ! Registers (MU)!

          Anatomy of Computer

Digital computers perform five major functions. These are 

   

 i. Inputting 

 ii. Processing 

 iii. Outputting

 iv. Storing

 v. Controlling 

   

i. Inputting :  Refers to the process of entering data into the computer, by the user using input device 

ii. Storing :     Refers to the holding of data and instuctions in the computer's main memory, for                                      manipulations.

iii. Processing : Refers to performing operation (both arithmetic and logical) or manipulation  of data                               entered into the computer so that userful information may be taken out of the entered                                  data 

iv. Outputting : Refers to the processor of showing the information or result the user either on screen                                 (monitor) or on the paper (through printer).

v. Controlling:  Refers to directing all the above processes, in coordination. This controlling is done by                             the Control Unit (CU) in a Central Processing Unit.

   

Consiering the main functions performed by a computer we can broadly classify the hardware Components into the following two types named as-

 

                                               Hardware (Physical Components)

   

Central Processing    Unit		Peripheral Device
	Input Device   Output Device   Memory

Central Processing Unit :

 The Central Processing Unit (CPU) is the brain of any computer system In a human body, all major decisions are taken by the brain and all other parts of the body functions directed by the brain Similarly in a computer system, all major calculations, manipulations and comparisons are made by the CPU. The CPU is also responsible for activating and controlling the operations performed by all other units of the computer system. The major parts of CPU are.

i. Arithmetic and Logic Unit (ALU).

ii. Control Unit

iii. Memory Unit or Registers 

Arithmetic Logic Unit (ALU)

 All calculations are performed and all comparisons (decisions) are made int he ALU. The data and instructions, stored in the primary memory prior to processing are transferred to the ALU where processing takes place All processing and manipulations of data is done in the Arithmetic and Logical Unit .

Control Unit (CU):

How dose input device know it is time for it to feed into the storage unit? How does the ALU know what should be done with the data once they are received ? And how is it that only the final results are sent to the output devices and not the intermediate results> All this is possible because of the control unit of the computer system By selecting interpreting and conforming to the execution of the program instructions the control unit is able to maintain order and direct the working of the entire computer system. Although it does not perform any processing on the data, the control unit acts as the central nervous system for all other components of the computer. It coordinates the entire computer system. 

Registers (MU)

 This is also known as internal Memory, it exists in the CPU internally. This is the temporary memory Data stored in the memory in the memory in binary digits. This memory is used at processing time CPU.