CENTRAL PROCESSING UNIT

Introduction

It is the brain of the computerFunctions of CPU

Manages the startup process Controls the flow of data, input and output

operations Loads program instruction and data into

memory and carries out the processing of data

Manages file and disk operations such as saving, retrieving, deleting files and formatting disks.

Components of CPU

CPU consists of ALU - Arithmetic Logic Unit Control Unit Immediate Access Store

The entire CPU is built on a single silicon chip called microchip and also known as Microprocessor.

CPU

INPUT OUTPUT

IMMEDIATE ACCESS

ALU CU

Arithmetic Logic Unit

Where the computer processes data either by manipulating it or acting upon it.

Consists of: Arithmetic Part - Performs the

calculations on the data e.g. 3 +2 = 5 Logic Part - Deals with logic and

comparisons. e.g. works out if one value is greater, less than or equal to another

Control Unit

CU main jobs: Monitors all the operations of the

computer system Making sure that all parts of the computer

do their jobs according to the instructions and in a proper sequence.e.g. When you want to print, the CU will keep

a check that the instruction are sent to the printer correctly.

Controls the flow of data within the CPU

Immediate Access Store

Holds the data and programs at the instant by the CU

It is also the working space of the computer. The processor brings all the program and

data to the memory unit before processing To make sure all operations are performed

in a proper sequence, the CPU uses the help of a clock

The clock is a device that synchronizes all the activities of a CPU, it ticks millions of times every second.

Speed of a Computer

Measured in hertz (Hz)One Hz means One tick per second or

One cycle per secondOne kilohertz (kHz) means 1000

cycles per second and One megahertz (mHz) means One million cycles per second

1mHz allows 1 million sets of activities to be completed per second

Speed of a Computer

The Computer power of a computer is determined by the Microprocessor type and its clock speed

Research activity. Find out some microprocessor models and its speed produced. Don’t forget the year it’s introduced.e.g. Pentium - Very high speed (66mHz) -

1993