European Computer Driving Licence

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European ComputerDriving Licence

• Module 1 Concepts of IT
• Chapter 1.4 Information Networks

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Local Area Network

• Computers which are linked by cabling in the same
  room or building
• A server controls the network and stores data
  which is used by other users on the network
  (clients),

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Networks

• Advantages
• Printers, scanners etc can be shared
• Work is stored on the server and can be accessed
  from any of the client computers
• Users can communicate and exchange data
• Software is loaded once onto the server rather
  than on individual computers

• Disadvantages
• Security measures are needed to stop users
  accessing programs and data
• Can be complicated to set up and requires support
  from skilled technicians
• Faults affecting the server will affect the
  client computers

4
Wide Area Networks

• A WAN connects computers in different
  geographical areas
• These are connected via the telephone system
• Used by multinational companies to communicate
  between different countries
• The worlds largest WAN is the Internet!

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The Telephone Network in Computing

• A modem is required for a computer to communicate
  over telephone lines
• Data is converted from digital to analogue and
  then back again
• The speed at which data is transmitted and/or
  received is measured in bits per second
• The current standard is 56,000 bits per second

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Public Switched Telephone Network

• PSTN for short!
• The international telephone system used for
  making day-to-day telephone calls
• It is the main reason why computers have become
  so popular in recent years!

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Integrated Services Digital Network

• ISDN for short
• Has a greater range of frequencies than PSTN
• At least as twice as fast as PSTN
• Typical transfer rate of 128,000 bits per second
• Data is transmitted simultaneously
• Special connection and modem required

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Asymmetric Digital Subscriber Line

• ADSL for short
• Uses telephone lines to transmit data at very
  fast speeds (512,000 bits per second)
• ADSL modem and splitters required to separate
  telephone signal from the ADSL signal
• You can still make telephone calls when surfing
  the web!

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The Internet

• Huge network of computers connected together
  (including yours)
• Minimum requirements are a 486 processor with
  Windows 95, modem, an account with an Internet
  Service Provider (ISP) and a telephone line
• The ISP provides access to the Internet through
  their servers
• Many ISPs do not charge as users will normally
  pay for the access via their telephone bills
• Many ISPs offer flat-rate access at fixed cost
  (e.g. AOL)

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E-Commerce

• Growth of the Internet in the last few years has
  been phenomenal
• Virtually any organisation has their own web site
• Virtually anything can be bought or sold over the
  Internet
• All banks offer online banking you can access
  your bank account 24/7
• The Internet is available 365 days a year it
  never closes!

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Purchasing Over The Internet

• You have to enter your name, address and
  credit/debit card details to purchase
  goods/services
• Most sites will offer a secure site which will
  scramble your details so it cant be intercepted
  by thieves
• Secure sites will start with the prefix https//
  - look out for the padlock symbol at the bottom
  of your screen

• You have the same consumer rights as buying from
  a shop

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Purchasing Over The Internet

• Advantages
• You can shop 24 hours a day, 7 days a week
• You can shop from the comfort of your own home
• You can surf the web to find the best bargains
• Many dealers will offer discounted prices for
  shopping online

• Disadvantages
• You cannot see or try goods before purchasing
• You may have to pay extra for delivery
• You cannot speak to a person for sales advice
• There is some degree of risk giving out your
  debit/credit card details over the Internet

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Alternative Payment Methods

• You can use online services to send money, as
  opposed to sending cheques
• NOCHEX (www.nochex.co.uk) lets you send and
  receive money from anyone with an email address
  and a debit card
• Paypal (www.paypal.com) offers a similar service

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E-mail

• By far the most popular use of the Internet
• E-mail messages arrive almost instantaneously,
  anywhere in the world
• The same message can be sent to more than one
  person at the same time
• It is very easy to reply to and forward e-mail
  messages

• Documents or photos can be sent as attachments
• E-mail software is required or you can access
  webmail providers online (e.g. Hotmail, Yahoo,
  Lycos etc)

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Intranets and Extranets

• Intranet is similar to the Internet but is
  internal to an organisation
• Users access the Intranet through a user name and
  password
• Enables users to share information and
  communicate via electronic messaging

• An Extranet can be accessed from outside the
  Intranet by authorised users via a user name and
  password