What is CPU (Central Processing Unit)? Parts (Components), Functions

What is CPU (Central Processing Unit)? Parts (Components), Functions

CPU Definition

Meaning – CPU stands for “Central Processing Unit“, and it also known as the “Processor” and “Brain” of computer system.


CPU is placed on its compatible CPU socket, which is embedded on the motherboard. CPU generates more heat while processing data, so it is connected with heat sink which helps to keep cool.

Importance of CPU

CPU plays vital role for performing great performance in computer system, and it helps in running all devices of system. CPU controls the all instructions, which are received from the system’s hardware and software, process them, and finally produces the result through output devices likes as monitor and printer etc. So, we can consider that CPU (Central Processing Unit) is more important part of computer system.

Parts of CPU

In this section, we will spread light on the all different CPU’s internal hardware parts names. Describe below each one.

Internal Components of CPU (Central Processing Unit) and their Functions

components of cpu
Memory Unit

Memory unit is the main components of CPU, because its main objective is to store all instructions, and pass them to other component of CPU (Control unit).

In the computer industries, computer memory is spited into two main categories such as primary and secondary memory. Entire performance, computing power, and execution speed of computer memory is totally depends upon its design layout and types like as (SRAM or DRAM).

After processing of all instructions by CPU, memory unit helps to store the generated output, and finally it is moved to output devices.

Control Unit

Main goal of control unit of CPU is to control entire operations of its units, and it helps to move all data or instructions in between the all units of system. Memory unit is received all instruction and data from control unit, interprets them, and finally transfer entire operations to different units.

Control unit is a communication medium between the all input and output devices to transfer or obtaining all instructions from memory units.

Arithmetic and Logic Unit

ALU is divided into two parts like as arithmetic and logic unit. It contains the digital circuit which is made with registers, and they help to solve the various arithmetic and logical operations. Arithmetic unit is designed to solve the different operations such as addition, subtraction, multiplication, division etc.

Prime functions of logic unit is to perform various types of operations like as comparing, selecting, matching and merging of numerous data value.

Input/Output Unit

Input unit means all input devices, which are used for inserting instructions from user side such as keyboard, mousetouchpad and more. Every input device consists own hardware controller which are linked to CPU and, and they provide the all instructions CPU that how to use them.

Output unit means all output devices, which are produced the result in the text or graphic form after processing the entire data that are given by user. Some output devices are monitor, printer, speaker etc. CPU grabs the binary code like as 0 or 1 and converts it into appropriate format which are needed by output’s hardware.

Other CPU Components Lists are –

System Bus – Prime objective of system bus is to transmits all data and instructions, as well as it sends the address locations that aware the CPU where in the main memory all data and instructions are receiving from and where processed data should be saved.

External Bus – It is communication medium in between the main data bus and system board.

Internal Data Bus – This type of data bus makes the connection between the all internal components of processor and motherboard. The size of internal buses are depended that how much information processor can process concurrently.

Address Lines – Address lines are designed to identify the appropriate location in the memory unit where data is presented.

Registers – Register is also known as “Accumulator”, and it works as temporary storage location where data is coming from main memory side for execution and move it for storing.

Flags – Flags are embedded into CPU, and they work as registers because they indicate the all currently running states of entire functions and other operations.

Cache – Cache is also integrated into chip, but it is fastest memory to primary memory, and it helps to increase the performance of processor.

Function and Uses of CPU

CPU is an input and output device because it receive data from memory unit for processing, and after manipulation move it to again memory unit for displaying result on the screen.

CPU obtains various instructions from input devices (mouse, keyboard, trackball), and processed them into four different phases then finally it produces the appropriate output.

Here, we will explain different four main functions of CPU (Central Processing Unit). Describe below each one.

Uses of CPU (Processor) and its Function

cpu function

Fetch Phase

In this phase, CPU fetches all instructions from the memory unit. All instructions are stored in the memory unit in own address location, and CPU gets the address number to fetch instructions with the help of program counter. When CPU fetch first instruction then program counter increases itself automatic, and then CPU takes next instruction in the consecutively.

Decode Phase

After completing fetching phase, CPU decides that what to perform next step of receiving data. In this phase, CPU decodes the fetched data with help of “Decoder Circuit”. These data are converted into Assembly instructions, and further Assembly instructions are decoded in the form of binary language, CPU easily can understand to binary instructions such as 0 and 1.

Execute Phase

After completing fetching and decoding phase, next phase execute to be performed, but it totally depend upon the CPU architecture, it means execution is done may be serially or parallel fashion.

Execution phase is completed into three steps such as done calculation along with ALU (Arithmetically Logical Unit), and then transfer data from one memory place to other place finally switch to their allotted address location.

Store Phase

After completing above three phases, CPU releases the finally feedback, then produced output data is moved to memory units for storing. But these memories have slow speed and cheaper to registers.C


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