2002 Information Technology: The infrastructure of the networked economy.
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Transcript of 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
VV AA XX
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
*
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
PE
RA
TIN
G S
YS
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PE
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UNUSED MEMORYUNUSED MEMORYO
PE
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MUNUSED MEMORYUNUSED MEMORY
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.