2002 Information Technology: The infrastructure of the networked economy

2002

Information Technology:

The infrastructure of The infrastructure of the networked economythe networked economy

2002

Elements of I.T.

• Infrastructure of the networked economy

• Hardware• Software

2002

Elements of IT

Typical Computer System

SpeakersKeyboard

Mouse

System UnitMonitor

Printer

2002

Hardware

• System unit–Memory–Input–Processing–Output

2002

Input

• Keyboard

• Mouse

• Barcodes

• Network

2002

Source Data Automation • Captures Data in Computer

Readable Form (Scanning)• WHY?

– Source Data Input– Reduce Errors– Increase Speed– Price Lookup– Inventory Control

2002

Source Input Techniques

• OCR -Optical Character Recognition

• UPC - Universal Product Codes

• Magnetic Strip

• MICR - Magnetic Ink Character Recognition

• OMR - Optical Mark Reader

• Page Scanners

2002

Other Input

• Touch Screen– Pressure sensitive

surface

– Reduce keyboard entry, Less errors

– More User friendly

• Data Collection Device – Used to collect data at

the site where the transaction takes place

• Meter reading , Inventory /Price check

2002

Voice Input

• Voice Recognition– Speaker Dependent

• Trained by Speaker

• Handicapped

– Speaker Independent• Limited vocabulary

• Postal Service

• UPS

2002

Processing• Central processing

unit (CPU)

• RAM

• ROM

2002

TYPES OF MEMORY

• RAM : Random Access Memory– Dynamic: Changes thru processing– Main memory for data and programs

• ROM : Read Only Memory – Program doesn’t change– Start-up

• Cache– Stores most frequently used instructions– Allows faster retrieval and execution

2002

Computer Power

• Two major factors: Speed and Memory capacity

• Speed is determined mainly by

– Clock Speed -- rate at which the CPU operates Measured in MHz, GHz, and MIPS.

– Word Size -- amount of information the CPU can process per cycle (32 bit chip processes 32 bits/cycle)

– Bus --number of bits that can be moved at one time between CPU and other devices; ideally word length and bus width will be at least equal

2002

Speed of Computer• Fractions of a second

1 millisecond = 1/1,000 (.001) second

1 microsecond = 1/1,000,000 (.000001) second

1 nanosecond = 1/1,000,000,000 (.000000001) second

1 picosecond = 1/1,000,000,000,000 (.000000000001) second

2002

PC Processor Types(Chips)

• Intel (90+%)– Celeron, Pentium III, Pentium 4– (600-700MHz) (650-866MHz) (1+GHz)

• AMD– AMD K6-2, Athlon

• Mac – Motorola

2002

Configurations…(high-end)

• Dell - • Pentium 4 – 1.5 GHz

– 128 MB RAM

– 40 GB Disk

– 56KB Modem+NIC

– 17” Monitor

– 8/4/32 CD/RW

– Surround w Subwoofer

– Small Business 2000

• Compaq -

AMD Athlon-1.2 GHz– 512 KB burst Cache– 128 MB RAM– 60 GB Disk– V.90 Modem+NIC card

– 17” Compaq Monitor– 12X DVD– 8X CD-RW– JBL Pro speakers

2002

Configurations… (middle)

• Dell - – Intel Celeron-900 MHz

– 256 Cache

– 128 MB RAM

– 20 GB Disk

– 15” Monitor

– 8/4/32 CD/RW

– 56 KB Modem

– Works/Money 2000

• HP - – Intel Celeron-900MHz

– 128 MB RAM

– 30 GB Disk

– 15” Monitor

– 48x CD-ROM

– 56 KB Modem

– Color Printer

2002

Computers Large and Small

• Differ by:– Physical Size

– Speed

– Memory size– $

IBMIBM AS400AS400

ZZZZZZZZZZZZZZZZ

2002

Computer Types

• Supercomputers• Mainframes• Minicomputers• Workstations/Servers• Microcomputers• Embedded Computers

CCRRAAYY

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SMART CARDBill SmithBill Smith

2002

Output• Monitor screen

–CRT or LCD

• Printer–Ink-jet printers–Laser printers

• Speakers

2002

Spoken Output

• Digitized– actual spoken word stored in digital form– Voice mail

• Synthesized– transfers words to speech– Raider Express

2002

Secondary Storage• Magnetic

– Diskette drive– Hard disks – Zip

• Optical– CD disks– DVD

2002

Optical Disks

• Written via Laser

• High volume of storage

• Very Durable

• Slower access time vs. magnetic

• Direct Access Storage Device

2002

• CD-ROM: 500-660 Megabytes– Land: Land: Flat Parts Of DiskFlat Parts Of Disk SurfaceSurface Reflects LightReflects Light

– Pits: Pits: Small Scratch On SurfaceSmall Scratch On Surface Scatters LightScatters Light

• WORM: Write Once / Read Many– CDRecordable

• Erasable Optical Storage (EOS) Disks– CDRW - ReWritable

– Magneto-Optical

*

OPTICAL STORAGEOPTICAL STORAGEOPTICAL STORAGEOPTICAL STORAGE

2002

Digital VVideoideo Disk• Hold 4.7 Gigabytes per layer per side

– home entertainment, educational, imformation

• Forms– Read-only (current)– Write-once (DVDR)– Single and dual layer

• 135 minutes playing time

2002

Other Storage Mediums

• Zip Drive (~$100)– 100 Megabytes Disk(~$12)– 250 Megabytes Disk

• Jaz and Jaz2 Drive (~$200 or $350)– 1 or 2 Gigabyte Disk (~$89 or $109)

• LS120 Drive ($150)– 120 Megabytes Disk (~$15)– Compatible with DD and HD diskettes

2002

Conceptual Computer

Speakers (output)

Monitor (output)

Printer (output)

CPU Chip (processing)

Internal Memory

Mouse (input)

Keyboard (input)

Data and Instructions

Data and Instructions

Information

Information

Modem (communications)

Data or Information

Data, Instructions and Information

Disk Drive (secondary storage)

2002

Data Representation

• Binary number system

• Bit• Byte (character)• ASCII code

2002

Data in Memory/Storage

• Bit: binary digit– small unit of data– 1 or 0 (on/off)

1010 1101

1010 1001

1011 0011

0101 0011

0101 0000

0101 0000

• Byte: group of bits (8)

– represents one number or one character (ASCII)

MIS300

2002

Data Storage

• Types–Internal memory (MAIN Memory)

–Secondary storage (Disks)

–Kbytes–Mbytes–Gbytes

2002

MEMORY SIZE• KILOBYTE (KT): 210 bytes... 1024 bytes• MEGABYTE (MB): 210 KB... ”million” bytes• GIGABYTE (GB): 210 MB... ”billion” bytes• TERABYTES (TB): 210 GB... ”trillion” bytes

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2002

SoftwareRelationship between types of software

Hardware

Operating System

Application Software

2002

HARDWAREHARDWARE

SYSTEM SOFTWARESYSTEM SOFTWARE

APPLICATION SOFTWAREAPPLICATION SOFTWARE

Software that manages the computer hardware resources

Systems Software

– Resource Management

• Memory

• Input/ Output

– File Management• Shared databases

– Scheduling– Monitoring– Utilities

2002

Types of Systems Software (OS)

• Single Task– One program

• Multiprogramming– Many programs, 1 CPU– Multitasking– Time Sharing

• Multiprocessing– Multiple CPU’s

Example Commands

Dir DebugFormat FdiskAssign EdlinDiskcopy Diskcomp

2002

MULTIPROGRAMMINGO

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UNUSED MEMORYUNUSED MEMORY

TRADITIONAL SINGLE-PROGRAM SYSTEMTRADITIONAL SINGLE-PROGRAM SYSTEM

PROGRAM 1PROGRAM 1

2002

MULTIPROGRAMMINGO

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PROGRAM 1PROGRAM 1

PROGRAM 1PROGRAM 1

PROGRAM 2PROGRAM 2

PROGRAM 3PROGRAM 3

TRADITIONAL SINGLE-TRADITIONAL SINGLE-PROGRAM SYSTEMPROGRAM SYSTEM

MULTIPROGRAMMING MULTIPROGRAMMING ENVIRONMENTENVIRONMENT

2002

WHY Multiprogramming?

• Better use of resources– Less idle time– Share CPU

• Only ONE program is “Active” at a specific time– Time In CPU Divided Into Slices (E.G.: 2

Milliseconds)– Each User Has Access To CPU During Slice– Since CPU Is Fast, Can Do Much During Time Slice– User’s Job Swapped Out At End Of Slice

*

2002

Multitasking

Multiprogramming

On A

Single-user System

Such As A

Microcomputer

2002

VIRTUAL STORAGEMethod Of Handling Several Programs In Primary

Storage:• Program Divided Into

– Fixed Length Portions (Pages) Or– Variable Length (Segments)

• Current Portions Reside In Primary Storage• Portions Swapped Out When Done• Better CPU usage• Better Memory usage

*

2002

Virtual Storage

2002

Multiprocessing

• Two Or More Parallel Processors In System

• Program Can Be Divided To Be Processed By Multiple CPUs

• Can Process Large Programs More Rapidly

• Increase Speed

• Back-up

*

2002

Multiprocessing

2002

Parallel Processing

2002

• Microsoft Windows– WINTEL

– Windows 95, 98, ME

– Windows NT

– Windows 2000

– Windows XP

Commonly Used Operating Systems

• UNIX• Linux• AX400• OS/2• Mac OS

2002

Applications Software

• Shrink-wrapped–Word processing–Spreadsheets–Database–Presentations

2002

Programs & Languages

Programming

• Computer language–Visual Basic

–C++

–Java

2002

Organizational Computing

• Mainframes–Dumb terminals–Host

• Client/Server–Desktop PC–Server

2002

Organizational Computing

Use of mainframes with terminals

2002

Organizational Computing

Mainframe Computing

Advantages & Disadvantages

Advantages Disadvantages

Centralized computing powerincluding management andbackup

Command-driven applicationdisplaying only text andnumbers

High levels of security High initial cost and cost ofupgrades to existing systems

Capability to run enterpriseapplications

Problems with failure ofcentralized computing inabilityto keep up with high demand

2002

• Personal computers–Local area network (LAN)

–Wintel

–Server• NT or Unix

Organizational Computing

2002

Organizational Computing

PC Advantages & DisadvantagesAdvantages Disadvantages

Standardized hardware andsoftware with ease of use(GUI)

High cost of management andsupport (total cost ofownership)

High user productivity Lack of centralized control

Low initial processing costs Security risks

Distributed computing Cost of software upgrades

2002

• Client-server computing–Workstation–Thin & fat clients–File server

Organizational Computing

2002

NETWORK COMPUTERS

• Thin Client• Simplified Desktop Computers

– CPU, Monitor, Keyboard, Network connection

• Programs and Data from central network or Internet (run under browser)

• Cheaper• Easier to keep current• More secure because central control

2002

Personal Data Assistants

• Palm Pilot– 3Com– Palm OS

• Palm PC’s– HP, Philips, Compaq….– Windows CE– Word, Excel

2002

Three-Tiered Client/Server Architecture

Organizational Computing

Request made toApplication Server

Results Returnedto Client

Query sent toDatabase Server

Matching DataReturned to

Application ServerClient Application Server Database Server

2002

Servers on a Client/Server Network

Organizational Computing

Server Type Purpose

File Provides both software and data files to users

Database Handles queries to a large database andreturns matching records

Application Handles high-speed processing for anapplication

Web Handles requests for Web pages

E-mail Sends and receives e-mail for entireorganization

Fax Sends and receives faxes for entireorganization

Modem Enables users in organization to access othernetworks through a telephone line

2002

Client/Server Network

Organizational Computing

FileServer

Fax/ModemServer PC PC Mail Server

NC DatabaseServer

ApplicationsServer

WebServer

2002

Advantages and Disadvantages of Client/Server Systems

Organizational Computing

Advantages DisadvantagesComputing burden can be sharedbetween clients and servers

Programming relationship betweenclients and servers is morecomplex

Servers can be specialized to oneparticular type of task

Updating system requires that allclients and servers be updatedregardless of location

Upgrading system can be done insmall steps

Loss of a client does not stop otherclients from accessing server

2002

Transaction Processing System

Foodorder

generated

Processing at fareastfoods.com

Credit card charged for

purchase

Food wholesaler ships food

items

Order sent over Internet

Food shippedto customer

2002

Processing Alternatives

ONLINE• Update as Input

• Random input

• Always Current

• Validate on input

BATCH• Data gathered and

processes at a later time.

• Not Current

• Good if data stable and doesn’t change often.