Transcript INTRODUCTION TO INFORMATION SYSTEMS TECHNOLOGY

Review For Final
(Fall 2007)
© Abdou Illia
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Computer Hardware
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The Core Computer Components
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Three subsystems in a computer system:
1. Input subsystem
2. Processing subsystem
3. Output subsystem
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Output Devices
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Monitors
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Cathode ray tube (CRTs)
Liquid crystal displays (LCDs)
Quality of display
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Resolution in pixels (e.g. 640 x 480)
Dot pitch in millimeters (.26 to .28)
Active-Matrix vs. Passive-Matrix display
Touch screens
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Input and output via display device
Monitor size
Common resolution
15 inches
640 x 480
17 inches
800 x 600 or 1024 x 768
19 inches
1024 x 768 or 1280 x 1024
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Printers
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Speed and resolution
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Pages per minute (PPM)
Dots per inch (DPI)
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Impact printers
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Number of ink dots to fill a square inch
Higher DPI = greater page clarity
Create image by striking paper and ribbon
Dot-matrix printers = most common impact printers
Non-impact printers
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Create image by spraying or rolling ink on the page
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I/O devices or Secondary Storage
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Nonvolatile storage of digital data
Magnetic or optical
 Magnetic storage (Floppy disk, Magnetic
tape, Zip disk, Hard disk)
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Sequential access (tape) or direct access (HDD)
Hard disk drives
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Two main standards:
 IDE (Integrated Drive Electronics) aka ATA (AT Attachment)
 SCSI (Small Computer System Interface)
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SCSI allows disk fault-tolerance through RAID – Redundant
Array of Inexpensive Disks
Disk speed:
 Transfer rate in MBps (Megabytes per second)
 Average Read Time (in milliseconds or ms)
 Platter rotation speed in RPM (5400/7200/10,000/15,000)
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Processing subsystem
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Two major components
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CPU (Central Processing Unit) or Processor(s)
Primary Storage:
 Random Access Memory (RAM)
 Read Only Memory (ROM)
CPU
Busses that
transfer data
Primary Storage
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Central Processing Unit
Processor
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Clock: generate time that
synchronize other components
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ICU: Fetches instructions from
RAM
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ALU: Execute instructions
(arithmetic & logic operations)
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Registers: Store control
information, data, intermediate
results
Clock
Instruction
Control Unit
Arithmetic
Logic Unit
Registers
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CPU speed
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Speed measured in hertz
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Hertz = # of instructions executed per second
Megahertz = 1 million of instructions per second
Gigahertz = 1 billion of instructions per second
Major Processor manufacturers
Intel
-
Celeron
- Pentium 3, Pentium 4, Pentium 4 Xeon, Dual Core
Advanced Micro Devices (AMD)
- K6 series processors (which compete with Intel Pentium 3)
- Athlon series (which compete with Intel Pentium 4)
IBM
- PowerPC 740, 750, 750FX, 750GL, 750GX
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Primary Storage
 Computer’s memory stored on semiconductor chips
 Two categories:
 RAM (Random Access Memory) which is volatile
 Synchronous Dynamic RAM (SDRAM)
 Double Data Rate SDRAM or DDR SDRAM
 ROM (Read-Only Memory) which is non-volatile
 Capacity in Megabytes (MB) or Gigabytes (GB)
Primary Storage
RAM
Program
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RAM holds running programs
and the data they use
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ROM contains critical
programs such as those that
boot the computer
Data
ROM
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Summary Questions
Book
Notes
1) Name three devices that could be used for both
input and output.
2) What is the difference between: (a) a Kilobyte and a
Gigabyte? (b) a Megabyte and a byte?
3) What is the function of the Instruction Control Unit
or ICU found in the processing subsystem?
4) Explain the difference between RAM and ROM.
5) What is pixel? What is dot pitch
6) What is a byte?
7) What is a Hertz?
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Software Technology
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Relationship of software to hardware
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Systems Software
Main Types of Software
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Systems software
Application Software
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Programs that manage computer hardware and
application software
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Three types of systems software:
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Operating systems (e.g. Windows, Linux)
Language translators (C++ compiler, VB compiler)
Utility programs (e.g. Norton Utilities)
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Main Types of Software
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Application software
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Programs that allow users to accomplish specific tasks
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Examples
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Word processing
Web browser
Tax preparation
Data management
Desktop publishing
E-mail
Groupware
Presentation graphics
Programming editors
Spreadsheet
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Operating Systems (OS)
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Software platform on which other programs run
Provides a connection between application
programs and the computer hardware
Major tasks
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Starting the computer
Managing files
Managing Programs and Memory (RAM)
Ensuring security
Providing a user interface
Example of OS: Linux, Windows XP, Windows
2000, UNIX.
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Managing Memory: Multiprogramming
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Managing Memory: Virtual Memory
￭ A technique that “extends”
primary memory (RAM) by
using secondary storage
devices
￭ Needed when there is not
enough RAM to hold programs
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Summary Questions
Book
Notes
1) What are the functions (or tasks) of an OS?
2) What do application programs allow?
3) What is the function of the Instruction Control Unit
or ICU found in the processing subsystem?
4) What is meant by virtual memory?
5) What is meant by multiprogramming?
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Network Technology
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Computer Network
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Once connected to the network,
the computer (or another device)
becomes a network node
An interconnection of computers and
computing equipment using either wires
or radio waves over small or large
geographic distances
GHI
DEF
ABC
MNO
“Connect to GHI”
JKL
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Physical
Transmission Media
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Physical media
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Wireless
Transmission media used to physically connect
nodes in to the network
Transmits electrical or optical signals
Could be cooper wire or fiber optic cable
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Transmission Media (Continued)
Twisted Pair
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Category
Use
Signal
Data rate
Distance
Problem
Category 1
Telephone
Analog/Digital
<100Kbps
3-4 miles
Security, noise
Category 2
T1, ISDN
Digital
<2 Mbps
3-4 miles
Security, noise
Category 3
LANs
Digital
10 Mbps
100 m
Security, noise
Category 4
LANs
Digital
20 Mbps
100 m
Security, noise
Category 5
LANs
Digital
100 Mhz
100 m
Security, noise
Category 6
LANs
Digital
250 Mhz
100 m
Security, noise
Category 7
LANs
Digital
600 Mhz
100 m
Security, noise
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Fiber optic
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Source
Thin glass fibers surrounded by coating
Uses lasers for light source
Very fast (10+ Gbps, 100 miles without any repeater)
Very secure
Photo diode
(LED or LD)
Photo receptor
Fiber optic cable (LED or LD)
Destination
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Wireless Media
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Uses electromagnetic waves or electromagnetic radiation
for data transmission
Propagation through space, and indirectly, through solid
objects
Two kinds of wireless media used
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Radio waves (radio Frequency)
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Infrared light
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Affected by Multipath interference
Highly vulnerable to snooping
Limited distance
Blocked by thick objects
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Close proximity and “line of sight” location required
Laptop
Comm.
Tower
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Network Topologies
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The configurations of network components
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How physically the network looks like
How logically data is transferred on the network
Widely used network topologies:
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Bus
Star
Ring
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Network Architecture
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Defines how the
processing takes
place on the network
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Two primary types
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Client-server
Peer-to-peer (P2P)
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Protocols
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An agreed upon set of rules that govern
communications in a network
Example: TCP/IP suite, Ethernet, Token Ring
Computer 1
Computer 2
Rules for Task 1
Rules for Task 1
Rules for Task 2
Rules for Task 2
Rules for Task 3
Rules for Task 3
Rules for Task 4
Rules for Task 4
Rules for Task 5
Rules for Task 5
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TCP/IP
TCP/IP suite is named after its two main protocols: TCP and IP
Transmission Control Protocol (TCP)
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Provides a reliable byte-stream transfer service between two
endpoints on an internet
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Internet Protocol (IP)
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Defines a delivery mechanism for packets of data sent between all
systems on an Internet
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It’s the protocol suite for the Internet
Task
Sample rules/protocols
Application
HTTP, FTP, SMTP
Transport
TCP, UDP
Internet
IP
Physical
Ethernet, Token Ring, PPP, Modem standards
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Ethernet
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A set of rules for transmitting messages in LANs
Most widely used protocol for LANs
Uses a method called CSMA/CD* for wired LANs
CSMA/CD*
1)
2)
3)
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All computers (“carriers”) listen (“sense”) for traffic on the LAN
If no traffic, computer that wishes to transmit may transmit
If collision occurs, computers must wait a random amount of time
The computer with smallest random number send again first.
* Carrier Sense Multiple Access with Collision Detection
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Token Ring
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Other set of rules for transmitting messages in LANs
Only one node “talks” at a time
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A node only transmit when it receives a special packet called
a “Token”
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Only one Token on the ring
No collisions
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Transmitting Data in a Network
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Two major techniques:
1) Circuit switching network
 Traditionally used for voice transmission
2) Packet switching network
 Used for computer data transmission.
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Summary Questions
Malaga
Notes
1) What is a node?
2) Name physical and wireless media used in networking
3) What transmission media is used for the telephone?
4) What are the main network topology? What are the
differences between them?
5) Distinguish between Client-server and P2P networks
6) Could collisions occur in Token Ring networks? In
Ethernet networks?
7) What is TCP/IP?
8) Distinguish between circuit switching and packet
switching.
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IS For Business
Integration
Refer to Review For Exam 3 material posted to the
course web site
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Development of IS
Refer to Review For Exam 3 material posted to the
course web site
35
Security and privacy
Refer to Review For Exam 3 material posted to the
course web site
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