Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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Introduction to Information Technology

2nd EditionTurban, Rainer & Potter

© 2003 John Wiley & Sons, Inc.

Chapter 3:Computer Hardware

Prepared by:Roberta M. Roth, Ph.D.

University of Northern Iowa

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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Chapter Preview

In this chapter, we will study:The hardware components of an

information system:• CPU (central processing unit)• Memory (primary and secondary storage)• Input devices• Output devices.

The classification of computers by power.

Strategic issues regarding hardware.

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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The Central Processing Unit (CPU)

InputDevices

SecondaryStorage

OutputDevices

ControlUnit

PrimaryStorage

ALU

Registers

The CPU

CommunicationDevices

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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The CPU (continued)

A microprocessor that executes instructions to perform processing tasks. Component parts are:Control UnitArithmetic-Logic UnitRegistersPrimary Storage

ControlUnit

PrimaryStorage

ALU

Registers

The CPU

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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The CPU (continued)

Control UnitAccess program

instructions Decode (interpret)

instructionsControl flow of data

throughout systemData flows through

paths called buses

ControlUnit

PrimaryStorage

ALU

Registers

The CPU

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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The CPU (continued)

Arithmetic-Logic UnitPerform computations on data Perform comparisons on data

ControlUnit

PrimaryStorage

ALU

Registers

The CPU

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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The CPU (continued)

RegistersHigh speed storage areas Hold data and instructions

ControlUnit

PrimaryStorage

ALU

Registers

The CPU

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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The CPU (continued)

Primary Storage (Main Memory)Stores instructions from programsStores data to be processed

ControlUnit

PrimaryStorage

ALU

Registers

The CPU

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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The CPU (continued)

Machine Instruction CycleAn instruction is fetched from primary

storage by the Control UnitThe Control Unit decodes the

instructionThe ALU receives the data and the

instruction and performs the calculation or comparison

The result is stored in primary storage.

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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The CPU (continued)

Computer performance is measured in part by the number of Machine Instruction Cycles performed per second.

Factors affecting this performance include:Clock SpeedWord LengthBus WidthLine Width

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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The CPU (continued)Microprocessors evolved rapidly due to

Miniaturation of transistorsDecreasing distance between transistors on

the chip (decreasing line width)Improved conductivity (flow) of electricityImproved instruction sets programmed into

the chip.Smaller, faster, cheaper, more powerful

chips with each generation.

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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Computer Memory

InputDevices

SecondaryStorage

OutputDevices

ControlUnit

PrimaryStorage

ALU

Registers

The CPU

CommunicationDevices

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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Computer Memory BasicsComputers are digital, and represent data

in bit patternsBit is shorthand for Binary digIT. The binary

system consists of two values: 0 & 18 bits = byteBytes are the basic measure of storage in

computersASCII Code assigns a unique character to

each pattern of 0s &1s in a byte.Kilobytes, Megabytes, Gigabytes, Terabytes

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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Primary Storage (Main Memory)

Main memory is a temporary storage area that holds three things…information you are working withthe application software you are usingthe operating system software

Increasing memory capacity increases the performance of the system

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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Primary Storage (Main Memory)

Types of Primary StorageRegisters – part of the CPU; very fast; very limited

capacityRandom Access Memory (RAM) – memory

chips on motherboard; general storage of program instructions and data; volatile

Cache Memory – faster than RAM; used to provide intermediate storage between secondary storage and RAM

Read-only Memory (ROM) – chips storing permanent instructions needed by computer; non-volatile

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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Secondary Storage

Non-volatile storage of data and instructions

Huge storage capacityCheaper than Primary StorageSlower than Primary StorageMagnetic and optical storage

media

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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Secondary Storage Types Magnetic tape

Cheap, slow, sequential access: good for backup Magnetic Disk

FloppyHard diskZip drive

Memory Cards and Cartridges Optical

CD-ROM, CD-RWDVD FMD-ROM

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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Storage for the Enterprise

Enterprise Storage Systems – provide coordinated, secure, managed storage for all enterprise data.Redundant array of independent disks

(RAID)Storage area networkNetwork-attached storage

Storage Service Providers – third party storage utilities

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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Computer Classifications

Computers are commonly classified by their processing power:SupercomputersMainframesMidrangeWorkstationsMicrocomputersComputing appliances

Classification boundaries are blurred.

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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Computer Classifications

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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Input Technology

InputDevices

SecondaryStorage

OutputDevices

ControlUnit

PrimaryStorage

ALU

Registers

The CPU

CommunicationDevices

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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Input Technologies

Human-orientedKeyboardMice / trackballTouch screensStylus JoystickMicrophone

AutomatedATMsPOSsOptical Scanners

• OMR• MICR• OCR

Voice recognitionSensorsCameras

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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Output Technology

InputDevices

SecondaryStorage

OutputDevices

ControlUnit

PrimaryStorage

ALU

Registers

The CPU

CommunicationDevices

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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Output Technologies

MonitorsPrintersVoiceMultimedia

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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Strategic Hardware Issues Productivity

Will employees’ personal productivity increase as microprocessor power and speed increases?

Changing Work Styles Will new work styles will benefit employees and the

firm as a whole? New Products and Services

Is the organization ready and able to take advantage of the new products and services that hardware advances may make possible for the business?

Improved Communication Is the organization ready to use multimedia for

knowledge sharing?

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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Chapter Summary

Basic role and function of the CPUPrimary and secondary storageClassifications of computers based on

processing powerVariety and purpose of input devicesVariety and purpose of output devicesConsideration of strategic issues raised

by the advances in hardware technology

Introduction to Information Technology, 2nd EditionTurban, Rainer & Potter© 2003 John Wiley & Sons, Inc.

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