The online world - learning aim B

The online world - learning aim B

1. The Internet

   • Internet
     • A worldwide computer network that used protocols to transmit and exchange data
   • Network
     • A group of computers cennected together and are able to communicate between eachother
   • Protocol
     • A set or rules that allows one system to connect with another
   • Internet Infrastructure
     • Connecting Backbone
       • Server
         • Router
           • Client
             • A computer that uses serveces provided by the server
           • Directs data packages to the correct destination/device
         • A computer/program that runs the needs of connected computers (LAN)
       • Large connecting routes (cables) between large and local networks
   • Types of Connection
     • Wireless
       • any network where is not pysical connection between sender and reciever
         • Portable devices, Multiple devices
           • Speed depends on location, Less secure
     • Broadband
       • Connection using Ethernet cables or connections to their network
         • Connection Reliablity, Can be faster
           • Not flexable
     • Dial-up
       • Connecting to a device via modem and public telephone network
         • Uses already exsisting wires and services
           • Very Slow, Errors, Cannot use phone at the same time
   • Badwidth and Transmission Rates
     • Bandwidth
       • A copacity a network has of how much can be carried and how fast
         • Speed of connection
     • Trasmission Rate
       • Measure of the number of bits transfered in a time scale
         • Bits per second or bit/s
     • Bit
       • Smallest peice of data
       • Bit/s
         • Number of peices of data transfereed per second

2. WWW

   • World Wide Web
     • Content is stored on web pages and connected to eachother via hyperlinks
       • The websites are connected to web servers that are connected to the internet
         • Computers connected to the web web browsers (eg. Google Chrome, Firefox)
           • The Web Browsers read the documents called HTML and translate it to the webpage as you see it
   • HTML
     • Hyperlink Markup Language
     • HTML is 'computer langauge' used to cerate web pages
       • You can create your own website using HTML
         • Allot of softwares exsist to use 'wizards'to create the code automatically
           • Whithin code you will have elements, they begin and end with tags
     • HTML examples
       • <html></html>
       • <body></body>
       • <h1>This is a heading</h1>
       • <p>This is a paragraph</p>
       • <i>This is italics</i>
       • <b>This is bold</b>
   • URL
     • Uniform Resorce Locator
     • a string of characters that identifies a specific web page
       • http://
         • www.google.co.uk/
       • https://
         • www.youtube.com/
           • watch?v=WaUzu-iksi8
       • Protocol
         • domain name
           • Path
   • Search Engines
     • Websites used to search for other webistes
       • When you search for websites you search the search engines database of recorded websites
         • You can specify your searches to fine websites, images videos, news ect.

3. Email

   • The sender and reciever do not have to be online at the same time
   • When someone sends an email is is stored on an email server until the recipient logs on, then it is forwarded to them
     • This is known as the store and forward system
   • Advantages
     • Address Book
       • Attachment
         • Multiple Recipients
           • Basically Free
             • Sends instantly (reciveing time deprends)
               • No age limit
                 • Available on multiple deices
                   • Anywhere where there is interntet
   • Disadvantages
     • Only know you have an email if you check manually
       • Security (can be hacked)
         • Reliablility
           • Uncolisited Bulk Email
             • Spam
               • Not garateed your email will be read
                 • Don't know if/when someone has recived it
                   • Viruses easily spred by opening emails
                     • Needs internet to recive
   • Features
     • To..
       • CC..
         • BCC
           • Blind Carbon Copy
             • Can't see other recipients
         • Carbon Copy
       • Main Recipient
   • Protocols
     • SMPT
       • POP3
         • IMAP
           • Internet Message Acess Protocol
           • Used to recive emails but keeps them on the web server
         • Post Office Protocol 3
         • Used to recive emails and download them onto your computer
       • Simple Mail Transfer Protocol
       • Used to send emails across IP networks (servers)

4. Data Exchange

   • All methods of passing data between devices, components and users, over a network
   • VOIP
     • Voice Over Internet Protocol
     • Sending voice and/or video over the internet
     • You need a microphone, speakers internet and for video also a webcam
     • It uses a peice of software that encodes and decodes data, sometimes known as a codec program
       • It digitizes an analogue voice signal and turns it into internet packets which it then decodes at the other end
   • Wireless Networks
     • Data is exchanged without cables or wires
     • Wireless connection uses radiowaves or infared
     • To connect to a wireless network your device needs a wireless interface card
       • The card is used to transmit data to and from the network