Definition
The term internet can be broken down into two words. Inter and Net which implies that there is an interconnection of networks.
Internet is therefore Inter connection of large network (network of networks) that covers the whole world and enables millions of computers to communicate globally.
In 1969, a research body in the USA called Advanced Research Projects Agency (ARPA) set up a computer network that connected four universities and was given the name ARPAnet. This network is viewed as the forerunner of today’s Internet. The aim was to allow sharing of data and information between computers. The aim benefit was that there was fast communication between researchers through electronic mail or E-mail.
Uses of Internet
Disadvantages of the Internet
-It is expensive
-Hacking/ gaining unauthorized entry to Computer system information
-Leads to immortality due to Pornographic
-Leads to passive leisure which can also be lazy behavior
-Some Virus are transmitted through the
Network Topologies
This is the physical organization/ layout of stations and devices in order to form a network.
Types of network topologies
Star
A network cable to a hub switch links every station to the rest of the network. It is most popular and reliable design for networks in one locality.
Bus
All the clients are connected to a common data communication medium (bus). There is no hub to link the devices. They communicate by sending messages to the common bus. This message is circulated to all computers on the network until the destination computer identifies and receives it. The disadvantage is that when the bus fails the entire network is affected.
Ring
Computers are connected in a circular format, one to each other and there is no hub to link them. It works like the bus design where a message is circulated to all computers on the network until the destination computer receives it. If there is a fault on one connection, the entire network is disabled.
Physical distance
A network can also be classified based on the distance between the devices connected. In this regard there are three main types;
*Local area Network (LAN) – connects computers within a short radius in a room, building or compound. It can also have multiple networks
*Metropolitan Area network (MAN) – connects computers within a wider radius but within a city or town .It can also have multiple networks
*Wide Area Network (WAN) – connects computers within a much wider radius beyond a city. It normally has multiple networks
Differences between Internet and Extranet
Intranet – when an organization uses the internet to communicate exclusive data/ information, this is referred to as Intranet
Extranet – an extranet is a private network that uses internet protocols network connectivity and possibly the public telecommunication system to securely share part of business information or operations with supplies, vendor partners, customers or other business.
Benefits of networking
Sharing resources
Improve efficiency
Avoids duplication of efforts
Harmonization of resources
Requirements when networking
Telecommunication facilities
Modems
Internet service providers (ISPs)
Internet software
Cables
Examples of Cables used for networking
Unshielded twisted pair (UTP) cable
Coaxial
Fibre optics
Internet Services
The internet has become very popular in today’s world because of the diverse but very important services that it offers to people. Some of the services provided are;
-The World Wide Web (www)
-Electronic Mail (E mail)
-Electronic commerce (e commerce)
-Electronic learning (e learning)
-Internet Fax
WWW
The World Wide Web can be viewed as a vast virtual space on the internet where information pages called websites are installed. Most local area networks have special computer called a server that stores information and data for others on he same network to access.
In order to connect a network to the internet, the local area network leads an internet server.
This server is usually given the name World Wide Web (www) and has all the information that others on the internet access. Thus said, www is created by a network of internet services called Hypertext Markup Language (HTML) to prepare documents called web pages that are attached and can be accessed on the internet.
Terminologies
URL - URL stands for Uniform Resource Locator. It is a special address given to websites.
http:// - stands for hypertext transfer protocol which is a protocol
TCP – transmission control protocol assists in intercommunication and transmission of data in a network
IP – internet protocol is a made rule of uniquely identifying computers in a network using numbers e.g. 191.162.0.50
Yahoo – is called the domain name of the local area network
Creating an E-mail account
E mail software falls under a special group of application packages called communication software. It is specially designed and developed to help a person to read and send individual text documents on the internet as long as both the sender and receiver have e mail addresses
Like the normal postal address, an e mail directs the computers on the internet on where the server of the e mail message is.
A typical email would look like this kamau_titus@yahoo.com
* kamau_titus is the username and is normally coined by the user during email account registration
* @ is the symbol for at which actually separates the user name from the rest of the address
* Yahoo.com is the name of the host computer in the network i.e. the computer on which the e mail account is hosted
* The period “.” Is read as dot and is used to separate different parts of the e mail address
* Com identifies the type of institution offering a particular service (s) and is called the domain meaning it is a commercial institution
Domain Types
.edu educational institutions
.gov government institution
.org non-profit making organization
.mil military organization
.co commercial institution
.ac university institutions
Sometimes another two letter extension is added after the domain name to show the country where the site is located e.g. in jsmith@yahoo.co.uk, .uk stands for United Kingdom. Other countries domain names include .ke (Kenya), .ug (Uganda), .tz (Tanzania), .jp (Japan), .au (Australia) etc.
Email facilities
Basically all e mail software packages provide the user with ability to receive messages, display them, reply to the messages, compose new ones and store received messages.
Mails
File attachment
E mail software also enables a person to attach other files like pictures, music & movie clips to an e mail for sharing with friends before sending. The recipient can then download the attached files or simply view them on the screen. A good example where people use attachments is on-line job applications where a person attaches curriculum vitae to an e mail message. To attach a file;
-Start the email software i.e. Microsoft Outlook express
-Click the then new or open a composed e mail
-Specify the recipients address and the subject
-Click the insert menu then file attachment. A dialog box appears where you chose the file you want to attach
-Select the file then click the attach button
-An attachment bar is inserted in the e mail window with a name of the file you chose
-Click send to send the email
You can also attach a file by simply clicking the attach button
Outline meetings
It is possible to hold on-line meetings with people by sending mail to them. For example, on-line interviews may involve a person sending electronic mail composed of interview questions to a recipient who can read and answer back immediately. This method may not be as effective as a face to face interview or discussion but it is very useful in situations where travelling may be impossible or too expensive
Telephone message
Because of integration between mobile telephony and the internet technology, it is possible to send e mail to a mobile handset and a mobile message to e mail account. This mobile computing is made possible by a special internet access protocol called wireless protocol (WAP) and wireless markup language (WML)
Contact management
Most mail programs allow the user to develop an address book which holds contact information like e mail addresses of different people along with other necessary information. The e mail software usually provides a simple way of accessing these contacts when required. To create a new contact;
-Start the e mail software i.e. Microsoft express
-From the tools menu, click address book or simply click the address book button
-From the address book window click File then contact
-Click the Add button and add the contact into the contact list
-Close the contract window then the address book
Electronic Learning (e Learning)
Apart from the fact that academic materials for all levels of education are readily available on the internet (web), the internet has opened the door for those who would like to do distance education programs and home schooling. Learning through interaction with special programs on the computer is called electronic learning (e learning).
Electronic commerce (e commerce)
Companies nowadays use the internet to sell and buy goods and services. This new business strategy where goods and services are sold over the internet is called electronic commerce.
One advantage of e commerce is that a company can access customers all over the world and is not limited by space and time. Hence, small companies that establish websites to auction their goods and services not only reduce operating costs but increase their sales. For example, most vehicle importers buy vehicles directly from international dealers by accessing their websites and placing orders.
However, the major challenges that face e commerce is that people deal with each other without ever meeting physically and there is lack of proper laws to govern such business.
Internet fax
The internet provides you with complete fax facilities from your computer. You can configure fax settings, send and receive faxes, track and monitor fax activity and access achieved faxes. Using fax, you can choose to send and receive faxes with a local fax device attached to your computer, or with a remote fax device connected to fax resources on a network.
Other Internet Services
*News media on the net – all major media house post their daily news on the internet for heir clientele to access information about an event. Can be sent right round the globe within a very short time
*Health information on the net – the internet provider latest medical news and research findings for practitioners and scholars
*Music and entertainment on the net – it is possible to listen to music on the web and to watch video clips if your computer is multimedia machine
*Chatting on the net – people can sign into a chat room and exchange ideas freely through discussion. Chat rooms are a common feature and usually put together people of common interest to exchange ideas. For example, if you sign into a chartroom for politics, then you can exchange political views with otherwise unknown internet friends who can read your typed comments as you view theirs. Try accessing www.try.com to see listings of chat topics that you can participate in on-line. However, you need to be careful in selecting the people to chat with on the web because some people who use the chat rooms have intentions of harming others.
Accessing the Internet
There are many applications that enable a person to access the internet. Such applications are called web browsers. Some of them have text interface .Perhaps the most common browsers in the world today are Netscape navigator, Mozilla Firefox and the internet explorer.
Therefore before accessing the internet, a person must start the browser software. There are some parts which appear in the internet explorer window
-The title bar
-The menu bar
-The toolbar with standardized
-The address bar
-The status bar
-Internet pages displayed here
-The toolbar and address bar
-The back button returns the browser to the immediate former web page
-The next button moves the browser to the next web page in case a person had clicked
-The stop button tells the browser to stop searching/ loading a website
-The refresh button tells the browser to try accessing a website address again after failure
-The search button enables a person to search for words on the website
-Clicking the favorites button displays all web address in the favorites folder
-The history button displays the website addresses that were visited in the recent past
-The mail button enables a person to view and send mail & web pages to links
-The print button enables a person to print the web pages
-The GO button tells the browser to load the current web page whose address is in the address bar
-The addresses bar allows the user to type the address of a web site to be accessed
-The home button moves the user to the first page of the website
Log In/ Sign In
To access a website type the full address of the website in the address bar then press the enter key on the keyboard. If the internet connection is working properly, the browser will start connecting to the requested website or URL. Notice that the status bar will be reading something like “connecting to site www.yahoo.com …
Some websites allow free access to al their pages by all visitors. However, others require people to be members hence a new visitor has to register (Sign Up) by filling some online forms. The registration process gives the visitor a user name and password that can be used to sign in or log in on the website for each successive visit. This is very common for email account providers like at www.mail.yahoo.com
Websites that give users a chance to log in are better especially if the services offered need some degree of privacy and customizing for individual customers e.g. it would be a gross mistake to have everybody accessing the other’s e mail account.
Surf/ browse
Surfing or browsing is the process of accessing internet resources like web pages and websites. This is done by either typing the URL addresses of a site in the address bar of the browser or by the following special links that lead to web pages called hyperlinks.
Hyperlinks and search engines
A hyperlink is a text or picture on an electronic document, especially web page that causes other web pages to open when the link is clicked. A hyperlink can be identified by the fact that the mouse pointer changes to look like a palm having four folded fingers with index finger not folded but pointing outwards.
The internet is a big forest of web pages and websites. Searching for particular materials or resources can be a nightmare because of the massive volumes of available documents and resources. To make the work a bit easy, special websites that maintain lists of hyperlinks are available. These websites are called search engines. They have special programs called robots or spiders that traverse the web from one hyperlink to the next and when they find new material they add them to their indexes or databases.
The user searches for a word by typing a few keywords in the search field of the engine then clicking the search button. The engine searches its database for links to the information requested and displays a list of links from which the user can now access information by clicking them to open web pages. Search engines include;
Downloading/ saving/ Printing web content
After searching & finding information on the internet, you may want to save the following information locally on your computer for future reference. The process of transferring information from a remote computer to a local storage is called downloading. To download a file, following procedure is followed;
-Right click the hyperlink to the file
-On the shortcut menu, click the save target as command
-After some searching the browser displays the save as dialog box. Specify the folder or drive where the file is to be saved then type a unique name for the file, in the name box
-Click the save button and the download progress dialog box appears on the screen. Unless otherwise selected, the download dialog box will notify the user at the end of the download process
-Open the file in its application to view it
N.B// If you download a file whose application is not currently installed on the computer, then you may not be able to view its contents. For example, if you download a file that was created in Ms Word then you only open it in the same application.
To print a file, open it in the application in which it was created then send it to the printer for printing. You can also print a web page directly from the browser window by clicking file then print.
Modem
A modem is an acronym made of two words, Modulators and de-modulator which is a device used to convert computers over the internet.
Mo-dulation - is converting analogue signal to digital signal (encoding)
Dem – modulation is converting digital signals to analog signals (de-coding)
Analog signals move by air
Digital signals move by cable
Rules of Emailing
-User must have a unique ID to the mailing server
-User must have a password minimum of 6 characters
-All email addresses must be in small letters
-Email addresses must not contain punctuation symbols
Internet security
Ensures data is transmitted safely over the internet using packet switching. A packet is a data carrier.
Parts of a packet
Internet ownership
No one person or country owns the internet. Literally, millions of governments, corporations, universities, commercial companies and citizens own the internet jointly. What this means is hat no one can control it in its entirety. In the USA there is a group called the National Science Foundation (NSF) that overlooks methods of improving the internets performance. The NSF is supported by a group called the internet engineering task force (IETF) committee. This committee has to conform to guidelines that are set by the Internet Architecture Board (IAB).
Data security and controls
Computer information systems are becoming more and ore important in daily life. Governments, private enterprises and individuals have found the need to protect data & information that is in their custody against unauthorized access, disclosure or damage.
Data and information security
*Protection of data & information against unauthorized access or modification
*Denial of data & information to unauthorized users
*Provision of data and information to authorized users
Data security also includes all the measures that will be taken to detect, document and counter the threats to data and information.
Data and information privacy
Private data or information is that which belongs to an individual & muss not be accessed by or disclosed to any other person unless with direct permission from the owner. Data or information held by a government or organization about people is confidential data. This data and information may be seen by many authorized persons without the knowledge of the owner. However, it should be used for commercial gain or any other unofficial purpose without the owner being informed. This data must also be protected against unauthorized access or disclosure
Unauthorized access
Data and information is always under constant threat from people who may want to access it without permission. Such persons will usually have a bad intention either to commit fraud, steal the information & destroy or corrupt the data. Unauthorized access may take the following forms;
Eavesdropping – tapping into communication channels to get information
Surveillance (monitoring) – this is where a person may keep a profile of all computer activities done by another person or people
Industrial espionage – spying on your competitor to get information that you can use to counter or finish the competitor
Control measures against unauthorized access
-Enforce data & information access control policies on all employees
-Encrypt the data & information transmission
-Keep the computer room closed when nobody is using it
-Reinforce the weak access points like doors & windows with metallic grills & burglar proof alarms
-Enforce network security measures
-Use file passwords to deter any persons who get to the electronic files
Control measures against computer errors & accidents
Control against theft
-Employ guards to keep watch over data & information centers and backups
-Burglar proof the computer room
-Reinforce weak access pints like windows, doors & roofing
-Create backups in locations away from the main computing center
Computer crimes
Detection & protection against computer crimes
Audit trial – a careful study of an information system by experts in order to establish or find out all the weaknesses in the system that could lead to security threats and weak access points for criminals
Data encryption – this is the mixed data to be read, understood and reconstructed by the sender and receiver
Firewalls – device or software that filters the data and information exchanged between different networks by enforcing the host networks access control policy
Log files- special system files that keep a record log of events on the use of the computers and resources of the information system
Laws governing protection of information
Although most countries do not have laws that govern data and information handling, the awakening has started and the laws are being developed. The right to privacy is expected by all people. Foe example the data protection law may have the following provisions;
*Data be not transferred to other countries without the owners permission
*Data and information should be kept secure against loss or exposure
*Data and information should be kept longer than necessary
*Data and information should be accurate and up to date
*Data and information be collected, used and kept for specifies lawful purposes
Therefore, the countries are encouraged to develop a data and information handling legal framework that will protect people’s data and information.