UNIT 3. Communication, networks and internet

Communication This growth in communication technology has revolutionized the way that businesses work and keep in touch with staff and customers.

Different communications SMS Smoke signals Flares Telephone Running Letters Drums Facial expression Facebook Myspace Skype s Sonar Oovoo ICQ Online gameplay MSN Languages Bird letters Grail Sign language Talking Fax Radio

Networks At home, your computer might be connected to its own printer and scanner. This works well as you are the only person who will be using them. Much of the time though, they probably aren't being used and just lie idle. A computer which isn't connected to a network is known as a ‘stand-alone.’ In a school or an office, it would cost a lot of money for every computer to have its own printer and for the majority of the time, like your printer at home, it wouldn't be used. By joining computers together to form a network, the are able to share one printer. This means that more money can be spent buying a better quality printer and that the printer is being used much more of the time. As well as sharing hardware, a network allows computers or users to share software and data. A computer connected to a network is known as a ‘work-station.’

Types of computer network Local area network (LAN) Wide area network (WAN) The internet Intranet Extranet VPN (virtual private network)

Differences Stand alone is a computer that can not connect with another in any way While work stations can connect to a network that connects many computers together.

How can you tell whether a computer is networked to other computers? Usually a networked computer will allow you to send messages to a fiend who is working on another computer. You will probably see messages telling you that you are entering a networked system when you logon. Sometimes you will have the choice to use a selection of printers. If you have a file server you are also likely to have some space on the servers disk reserved for you to save your work.

A file server This is a powerful computer that runs the network operating systems and allows resources to be shared over the network by other devices and computers (called clients) connecting to it These devices should include printers, disk drivers, CD-ROM drives, modems. Cameras, fax machine etc. File server should be kept in a cool room, dust free, and secured.

A print server Coordinates printing on the network

Advantages of LANs Software and data files can be shared Users can work together on a single shared document Users can communicate; for example, using instant messaging or Users can stream media, so that they can view video and play audio on any computer or other device attached to the network.

Advantages of LANs Users can be access the network from any other workstation or device Cheaper to buy one copy of a software application and pay a license fee for several computers than to buy individual licenses Users can share hardware devices Users can share internet connection Users’ access right can be controlled centrally Can do maintenance work on computers from a central location

Types on LAN Client-/server networks Peer-to-peer network

Client/server network One or more computers are designated as the server Client computers are those available to you to use

Peer-to-peer Allows every computer to communicate directly with every other computer in the network A user can access data from any computer on the network This type if LAN is limited to about 10 machines, after which the performance drops and the system becomes slow They are used mainly in small businesses and departments

Cabled LAN vs. wireless LAN All computers and other peripheral devices on the network are attached to cables that transmit data between them. A network cable is required Uses a wireless link to connect to the network Has three sets of components wireless points, wireless interface cards, routers, slower transmission speed that a cabled LAN

Internet The internet in a WAN A network of bank cash dispensers is a WAN A school network is usually a LAN LANs are often connected to WANs, for example a school network could be connected to the internet WANs can be connected together using the internet, leased lines or satellite links.

What is the internet? The internet is an international network of networks that connects people worldwide. It consists of:  WWW- world wide web  Forums where people can seek help and advice about a topic  Research databases used by universities and large companies  USENET – discussion groups about a specific subject from a latest boy band to favorite pets  and instant messaging systems

Continue Note that no one ‘owns’ the internet Each part of it is made up of individual networks that someone has put together and then linked to the internet However, each network has to obey the internet standards in order to connect. And there are a groups set up by the U.S government.

Connecting to the internet - ISP An ISP (internet service provided) sells internet access to companies and individuals. It provides web servers which connect to the internet. An ISP will provide it’s customers with a wide range of services…  Bandwidth options  services  Web hosting  Online and telephone assistance.

Connecting to the internet - ISP Dial up or narrow band  Is when the computer dials a phones number to connect you to your ISP using a telephone line. Broadband  A single cable that can provide cable TV, telephone and internet services  Available over a telephone line or cable, or mobil telephone network

Connecting to the internet - hardware A computer An internal or external modem or similar device Satellites, fiber-optic cables or radio waves

Connecting to the internet - software TCP/IP (transmission control protocol / internet protocol)  A set of protocols used to transfer data from one computer to another over the internet  A protocol is a set of rules that defines how computers interact or communicate with each other  Most modern operating systems implement the TCP/IP standard.

Connecting to the internet - software Browser software allows users to view and use the web pages on the internet  The address bar  A navigation bar  A bookmark/ favorites option  A search engine  A history button  Browser setting and internet options e.g. filtering

Connecting to the internet - others Web addresses or URLs URL – uniform resource locator

Connecting to the internet - others Internet address  Every device on the internet has a unique address that identifies it. This address is a number called the IP address  The IP address could be static (it remains the same every time you connect to the internet) or dynamic ( a temporary address that changes every time you connect to the internet)

WWW The world wide web is a multimedia service that runs on the internet The web consists of hypertext and hypermedia documents This documents contain hyperlinks to other documents located on the same computer or on another computer in any part of the world All the information that can be accessed via the internet is often called cyberspace.

URL table.doc

Save files and their names Ms word: timetable.docx Ms excel: timetable.xlsx Ms PowerPoint: timetable.pptx Ms access: timetable.ink A text editor: timetable.txt A zipped file: timetable.zip A webpage: timeline.html A pdf file: timetable.pdf

What can you do in the internet and on the web? View web pages Use a search engine to find pages you want Send and receive s Use online shopping (e-commerce) Online banking (e-commerce) Bet online Customer support Software download and distribute Access and discuss information via mailing lists, bulletin boards and new groups chat online Video conferencing Web broadcasting Set up your own website or blog or wiki Use social networking sites to communicate with a closed circle of friends

Cons and pros and impact of these on society Choose 2: Online shopping Online banking Social networking Web broadcasting

Online shopping

The good:  Fast and generally secure  Sometimes you receive discounts on products from the company  Access from any computer with internet  Shops available worldwide 24/7 The bad:  Personal security  Delivery fees  Product might get broken on delivery

Online shopping Online shopping has made our society a lazy It made people sit at home and shop for things instead of going to the shops to get to buy it The shopping has made actual shops, make much less money forcing them to also open online shopping sites to bring back the customers. Has made people waste less gas to go to the shops

Social networking

Social networking good vs. bad The good:  It doesn't cost anything to use it  It gives you easy connection to all your friends, past and new  Its very easy to use and help connect with others The bad:  Lack of anonymity  People can scam you online  People can harass and bully each other online  It is very time consuming communicating with all your friends

Social networking and affecting our sociaty It made everyone connect with old long lost friends It made connecting with people around the world easy Made our society even more lazy