Presented byAbhijit Roy

MCA(1st Sem)

North-Eastern Regional Institute of management

Pronounced as separate letters, CPU is the abbreviation for central processing unit. Sometimes referred to simply as the central processor, the CPU is the brains of the computer where most calculations take place. In terms of computing power, the CPU is the most important element of a computer system.In other words A central processing unit (CPU), also referred to as a central processor unit, is the hardware within a computer system which carries out the instructions of a computer program by performing the basic arithmetical, logical, and input/output operations of the system.

Central Processing Unit(C.P.U)

Block diagram of cpu

InputDevice

OutputDevice

Control Unit

ALU

Primary Memory

Secondary Memory

CPU

Basic Components of CPUControl Unit(CU): which controls all the

operations of computer systemArithmetic & Logical Unit: which performs all

arithmetical & logical operations . Arithmetical operations include addition , multiplication, division, subtraction . Logical functions include <,>,= etc

Memory(Register) : which holds the temporary data for specific function.

Control Unit CUPart of the hardware that is in-chargeDirects the computer system to execute

stored program instructionsCommunicates with other parts of the

hardware

Arithmetic & Logical UnitsCalculations occur hereIt knows how to perform operations

such as ADD, SUB, LOAD, STORE, . It knows the commands that make up

the machine language of the CPUIt is the calculator

RegistersHigh-speed

Temporary storageLocated inside CPU

Instruction register

Holds instruction currently being executed

Data register

Holds data waiting to be processed

Holds results from processing

How do CPUs work?

Control Unit- Manages four basic operations (machine cycle)

Fetch- Gets next program instruction from the computer’s memory

Decode- Figure out what the program is telling the computer to do

Execute- Perform the requested action

Write-back (Store)- Write (store) the results to a register or to memory

Control unit ALU

Memory

How a CPU works

Example How CPU works

What’s inside the CPU?

Motherboard (mainboard)- Large printed circuit board with thousands of electrical circuits

Power supply- Transforms alternating current (AC) from wall outlets to direct current (DC) needed by the computer

Cooling fan- Keeps the system unit cool

Internal Speaker- Used for beeps when error is encountered

Drive bays- Housing for the computer’s hard drive, floppy drive and CD-ROM / DVD-ROM drives

INSIDE CPU

What are the types of Processor?

IntelAdvanced Micro Devices (AMD)

CyrixMotorola (Apple)

Pentium IV

Pentium MMX

Pentium III