What is CPU?

Central Processing Unit (CPU):

                                                              CPU is considered as the brain of the computer. CPU perform all types of data processing operation. It stores data,intermediate results and instructions. It controls the operation of all parts of computer. CPU itself has following three components.

1.ALU:

            The unit consists of two subsection namely:¹ Arithmetic section. ² Logic section.

(a) Function of Arithmetic section is to perform operation arithmetic operations like addition,subtraction,multiplication & division. All Complex operations are done by making repetitive use of above operation.

(b) functions of logic section is to performed operation such as comparing selecting,matching &merging of data.

The Arithmetic and logic unit contain a number of storage locations referred to as registers.These registers are composed of electric circuitry having the capability of adding,subtracting,multiplication,rounding off etc.The number of register in a computer very form model to model. However ,the basic register in any computer are the adder and the accumulator.

2 Control Unit :

                             Control unit controls the operation of all part of Computer. It does not carry out any actual data processing operations.

•Function of this unit are:

  (a) It retrieves instructions from the main memory and determine. what is to be taken.

  (b) It then retrieves the data required to be processed from the main memory.

 (c) It cause the CPU to actually carry out required operations and determine weather the required operation has been carriedout or not.

 (d) It places is the process result in the output area of the memory.

3 Memory Or Storage  Unit:

                                                      This unit can store instructions,data and intermediate results.This unit supplies information to the other unit of the computer when needed.It is also known as internal storage unit or main memory or primary  storage or Random Access Memory (RAM). Its size effects speed, power and capability.The main memory can be divided into four area that have no fixed or build in physical boundaries within the memory.These areas are: ¹  Input storage area ²Working storage area ³Output storage area ⁴Program storage area.

There are two types of memories in the computer.The first type is called as primary memory and the other type is called as secondary memory.The primary memory offers temporary storage and the secondary memory provide permanent storage. The detailed Converse of memory has been given in the coming chapters.