Transcript Information Technology:

Information Technology:
The infrastructure of
the networked economy
2002
Elements of I.T.
• Infrastructure of the
networked economy
• Hardware
• Software
2002
Elements of IT
Typical Computer System
Monitor
System Unit
Speakers
Printer
Keyboard
Mouse
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?
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Source Data Input
Reduce Errors
Increase Speed
Price Lookup
Inventory Control
Source Input Techniques
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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
2002
• Data Collection
Device
– Used to collect data at
the site where the
transaction takes place
• Meter reading ,
Inventory /Price check
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
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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
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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
Configurations… (middle)
• Dell -
• HP -
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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
Intel Celeron-900MHz
128 MB RAM
30 GB Disk
15” Monitor
48x CD-ROM
56 KB Modem
Color Printer
ZZZZZZZZ
Computers Large and Small
• Differ by:
– Physical Size
– Speed
– Memory size
–$
IBM
2002
AS400
Computer Types
SMART CARD
Bill Smith
2002
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C
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Supercomputers
Mainframes
Minicomputers
Workstations/Servers
Microcomputers
Embedded Computers
V
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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
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Optical Disks
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Written via Laser
High volume of storage
Very Durable
Slower access time vs. magnetic
Direct Access Storage Device
2002
OPTICAL STORAGE
• CD-ROM: 500-660 Megabytes
– Land: Flat Parts Of Disk Surface Reflects Light
– Pits: Small Scratch On Surface Scatters Light
• WORM: Write Once / Read Many
– CDRecordable
• Erasable Optical Storage (EOS) Disks
– CDRW - ReWritable
– Magneto-Optical
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Digital Video 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
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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)
CPU Chip
(processing)
Mouse (input)
Data and
Instructions
Data and
Instructions
Keyboard (input)
Data or
Information
Modem
(communications)
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Information
Internal Memory
Information
Data, Instructions
and Information
Disk Drive
(secondary storage)
Monitor
(output)
Printer (output)
Data Representation
• Binary number
system
• Bit
• Byte (character)
• ASCII code
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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
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• Byte:
group of bits (8)
– represents one number
or one character (ASCII)
M
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3
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Data Storage
• Types
–Internal memory (MAIN Memory)
–Secondary storage (Disks)
–Kbytes
–Mbytes
–Gbytes
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MEMORY SIZE
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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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Software
Relationship between types of software
Application Software
Operating System
Hardware
2002
Systems Software
APPLICATION SOFTWARE
SYSTEM SOFTWARE
HARDWARE
– Resource
Management
• Memory
• Input/ Output
– File Management
• Shared databases
Software that
manages the
computer hardware
resources
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– Scheduling
– Monitoring
– Utilities
Types of Systems Software (OS)
• Single Task
– One program
• Multiprogramming
– Many programs, 1 CPU
– Multitasking
– Time Sharing
• Multiprocessing
– Multiple CPU’s
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Example Commands
Dir
Format
Assign
Diskcopy
Debug
Fdisk
Edlin
Diskcomp
MULTIPROGRAMMING
OPERATING SYSTEM
TRADITIONAL SINGLE-PROGRAM SYSTEM
2002
PROGRAM 1
UNUSED MEMORY
MULTIPROGRAMMING
2002
PROGRAM 1
UNUSED MEMORY
MULTIPROGRAMMING
ENVIRONMENT
OPERATING SYSTEM
OPERATING SYSTEM
TRADITIONAL SINGLEPROGRAM SYSTEM
PROGRAM 1
PROGRAM 2
PROGRAM 3
UNUSED MEMORY
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
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2002
Multitasking
Multiprogramming
On A
Single-user System
Such As A
Microcomputer
2002
VIRTUAL STORAGE
Method Of Handling Several Programs In Primary
Storage:
• Program Divided Into
– Fixed Length Portions (Pages) Or
– Variable Length (Segments)
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Current Portions Reside In Primary Storage
Portions Swapped Out When Done
Better CPU usage
Better Memory usage
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Virtual Storage
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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
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Multiprocessing
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Parallel Processing
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Commonly Used Operating
Systems
• Microsoft Windows
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WINTEL
Windows 95, 98, ME
Windows NT
Windows 2000
Windows XP
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UNIX
Linux
AX400
OS/2
Mac OS
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
2002
Disadvantages
Centralized computing power
including management and
backup
High levels of security
Command-driven application
displaying only text and
numbers
High initial cost and cost of
upgrades to existing systems
Capability to run enterprise
applications
Problems with failure of
centralized computing inability
to keep up with high demand
Organizational Computing
• Personal computers
–Local area network
(LAN)
–Wintel
–Server
• NT or Unix
2002
Organizational Computing
PC Advantages & Disadvantages
Advantages
2002
Disadvantages
Standardized hardware and
software with ease of use
(GUI)
High user productivity
High cost of management and
support (total cost of
ownership)
Lack of centralized control
Low initial processing costs
Security risks
Distributed computing
Cost of software upgrades
Organizational Computing
• Client-server
computing
–Workstation
–Thin & fat clients
–File server
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
Organizational Computing
Three-Tiered Client/Server
Architecture
Request made to
Application Server
Results Returned
to Client
Client
2002
Query sent to
Database Server
Matching Data
Returned to
Application Server
Application Server
Database Server
Organizational Computing
Servers on a Client/Server Network
Server Type Purpose
File
Provides both software and data files to users
Database
Handles queries to a large database and
returns matching records
Handles high-speed processing for an
application
Handles requests for Web pages
Application
Web
E-mail
Fax
Modem
2002
Sends and receives e-mail for entire
organization
Sends and receives faxes for entire
organization
Enables users in organization to access other
networks through a telephone line
Organizational Computing
Client/Server Network
File
Server
Fax/Modem
Server
NC
2002
Database
Server
PC
PC
Applications
Server
Mail Server
Web
Server
Organizational Computing
Advantages and Disadvantages
of Client/Server Systems
Advantages
Computing burden can be shared
between clients and servers
Servers can be specialized to one
particular type of task
Upgrading system can be done in
small steps
Loss of a client does not stop other
clients from accessing server
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Disadvantages
Programming relationship between
clients and servers is more
complex
Updating system requires that all
clients and servers be updated
regardless of location
Transaction Processing System
Order sent
over Internet
Food
order
generated
2002
Processing at
fareastfoods.com
Credit card
charged for
purchase
Food shipped
to customer
Food
wholesaler
ships food
items
Processing Alternatives
ONLINE
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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.