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Volume 1Volume 1

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A. Basic Components of a Central A. Basic Components of a Central Processing Unit (CPU)Processing Unit (CPU)

a single microprocessor

Many magazines introduce the latest models of CPUs

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Three Basic Components of CPUThree Basic Components of CPU

(a) Control Unit (CU) (a) Control Unit (CU) extract the instructions from the main

memory, decodes them and executes them

(b) Arithmetic and Logic Unit (ALU)(b) Arithmetic and Logic Unit (ALU) perform all arithmetic computations

and all logic operations

(c) Register(c) Register store temporary data for use

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B. Bus ConnectionsB. Bus Connections

a collection of wires through which data is transmitted from one part of a computer to another

CPU

Memory chips

Bus

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Three Types of BusesThree Types of Buses

(a) Address bus(a) Address bus identify particular memory addresses

(c) Data bus(c) Data bus carry actual data that is being processed

(b) Control bus(b) Control bus control instructions between the CPU

and other internal devices

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C. Functions of the CPUC. Functions of the CPU

(1) Booting Up a Computer System(1) Booting Up a Computer System

CPUCPU BIOSBIOS

Free the operating system and Free the operating system and its application programs from its application programs from

learning the hardware addresses learning the hardware addresses so they need not be changed so they need not be changed

when the device details change.when the device details change.

Manage data transfer betweenManage data transfer betweenthe operating system ad attachedthe operating system ad attached

hardware devices.hardware devices.

Load the operating systemLoad the operating system (from the hard disk or floppy disk) (from the hard disk or floppy disk)

into RAM.into RAM.

Boot up a computer system.Boot up a computer system.

Determine all attachments Determine all attachments are in place and optional.are in place and optional.

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(2) Running Program Instructions(2) Running Program Instructions

RegistersRegisters

RegistersRegisters

RegistersRegisters

RegistersRegisters

ControlControlUnitUnit

ALUALU

MainMainMemoryMemory

0000 LDA 20000000 LDA 20000004 0004 ADD 2004ADD 20040008 JPN 300C0008 JPN 300C000C SUB 2008000C SUB 2008

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Intel CeleronIntel Celeron, , Intel PentiumIntel Pentium and and

AMDAMD are three common types of are three common types of

CPU. State their differences and CPU. State their differences and

compare their advantages and compare their advantages and

disadvantages.disadvantages.

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