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Computer Studies

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Title: Computer Studies


1
Computer Studies
  • Computer communication and networking

2
Group
Author
  • Lam Ka Po, Angela 98104740
  • Ma Wai Kin, Winky 98104410
  • Lam Chi Man, Andy 98104660
  • Each of the team member is responsible for 2 of
    the 6 sections

3
Introduction
Target audience S5 science students with
average ability Attitude Active, eager for
learning, interest in Internet Background
Knowledge Simple concepts of data communication
  • For lecturing purpose
  • Questions are incorporated in the presentation
  • Use of large amount of figures and animations to
    illustrate abstract concepts of networking
  • Last section serves as a practical activity
    involving students participation
  • Small test will be given on papers at the end of
    chapter

4
Table of contents
  • Concept of computer communication
  • The need for networking
  • Types of networks
  • Network topology
  • Means of communication
  • Use of world wide web (W W W)

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5
Concept of computer communication
6
Concept of computer communication
Data
Telephone Line
7
Stage of communication
Where each stage take place ?
  • Encoding
  • Transmission
  • Decoding

Sending device
Receiving device
8
Encoding
  • Information (e.g. data, text, voice or video)
    from the sending device is converted into signals
    which the communication medium can carry

9
Transmission
  • The signals are transmitted through the medium to
    the receiving device

Signal transmitted by telephone line
Sending device
Receiving device
10
Decoding
  • The signals are converted back into the
    information in its original form in the receiving
    device

11
Computer Network
Server
12
This is the end of Concept of Computer
Communication
Back to Table of Content
Next Section
13
The need for networking
14
Sharing of resources
15
Sharing of resources
Connected
Connected
16
Sharing of resources
  • Sharing data, programs and hardware
  • Data and software can be centrally stored in a
    computer acting as the file server and accessed
    by any computer in the network
  • An expensive laser printer can be connected to a
    computer which serves as a print server and
    processing printing jobs from other computers

17
Communicate with one another
IBM PS/2
Mac
18
Communicate with one another
  • Different types of computers store data files
    using different internal representation methods
  • A network operation system can automatically
    convert the files into the required
    representations before they are transferred

19
Centralized control and Better security
The network supervisor
better security measures
centralized control over all facilities and
resources
20
Centralized control and Better security
  • The network supervisor can have a centralized
    control over the use of all facilities and
    resources
  • including all data, programs, disk spaces and
    other hardware
  • better security measures can be applied

21
Easier software management
Server
Install new software
Use new software
Use new software
Use new software
22
Easier software management
  • When a new applications is developed and
    installed in the server, workstation can
    immediately use it from any computer
  • upgrading or changing software is simpler because
    it is now stored in the single file server but
    not distributed among different computers

23
Flexibility of location
Server
24
Flexibility of location
  • Any computer on the network can be used to access
    the centralized database or the software and data
    in the file server
  • it is fairly easy to add a workstation anywhere,
    relocate a computer to another site, to add a new
    printer or any other resources

25
This is the end of The Need for Networking
Back to Table of Content
Next Section
26
Types of networks
27
Local Area Network
- Within a room, floor or building
FAST!
28
Metropolitan Area Network
- Within a large city - Optical fibers as media
29
Wide Area Network
- link small networks in different geographic area
30
This is the end of Types of Networks
Back to Table of Content
Next Section
31
Network topology
  • It refers to the way by which the network
    hardware (called nodes) are arranged and the
    means if data flow.

32
Star architecture
Host
Node
33
Star architecture
Host
Node
34
Star architecture
Host
Node
35
Star architecture
  • Host fails,
  • whole network breaks down
  • Node fails,
  • network not affected
  • Configuration is simple

36
Ring architecture
I know u love me, but I hate u !
Oh, not for me, I will pass the message
All Computer are nodes
37
Ring architecture
????
Oh, I cant transfer your message!!
38
Ring architecture
  • All computers are
  • Nodes
  • If any node fails,
  • whole network break down

39
Bus architecture
Not my message, I wont pick up
What! The deadline has changed??
Not my message, I wont pick up
Its my message, I will pick it up
Node
BUS
Not my message, I wont pick up
You have to hand in your homework today!
40
Bus architecture
Not my message, I wont pick up
What! The deadline has changed??
Its my message, I will pick it up
Node
What will happen?
BUS
Not my message, I wont pick up
You have to hand in your homework today!
41
Bus architecture
  • All Nodes connected to
  • BUS
  • If any node fails,
  • network not affected

42
This is the end of Network Topology
Back to Table of Content
Next Section
43
Means of communication
44
Two ways of transmission data
  • 1. Direct mode transmission

Signals are transmitted to a particular receiver
45
2. Broadcast mode transmission
46
Direct mode transmission
  • 1. Twisted wires

47
2. Coaxial cable
48
  • 3. Optical fibre
  • Very expensive transmission medium
  • Not subject to electrical disturbance
  • Suited for long distances communication in high
    data rate

- Light passes along the coated fine cylindrical
glass tubing by reflection
49
Broadcast mode transmission
Satellite transmission
Ground station receive the data and beam to the
satellite by microwave
Satellite will re-transmit data to another ground
station
50
This is the end of Means of Communication
Back to Table of Content
Next Section
51
Use of world wide web(WWW)
The Internet
52
What is Web Browser ?
Web Browser is a software to 1. Traverse the
links in the Web 2. Communicate with
servers 3. Retrieve data
53
Two popular Web Browsers
1. Netscape
2. Internet Explorer
54
Use of Web Browser
55
(No Transcript)
56
  • You can see some shortcut key on the browser like
    this

57
  • Address of Web Site is called URL(Uniform
    Resource Locator)
  • e.g. http//www.singtao.com

http//www.singtao.com
58
  • After that, you can browse the home page that you
    wanted.

59
Suggestions of Interesting Web Sites
  • Newspapers
  • Singtao Daily News
  • http//www.singtao.com/
  • Apple Daily News
  • http//apple.daily.com.hk/

60
  • Christmas Card Web Site
  • http//www.comp.hkbu.edu.hk/c6000171/xmas
  • http//www.casema.net/pico/kerst/
  • Meteor shower
  • http//www.glink.net.hk/sohk/leonid/enter.htm

61
  • Games
  • Cow boy http//www.shinenet.com.tw/fashion/game92/
    index.html

62
  • Matching Games
  • http//personal.cityu.edu.hk/96013494/matching/

63
  • Game
  • http//personal.cityu.edu.hk/96013494/fool/fool.
    htm

64
  • Comics
  • ????
  • http//home.hkstar.com/fucp/fujiko/doraemon/dora
    .htm

65
This is the end of Use of World Wide Web
Back to Table of Content
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