Internet and World Wide Web

WEEK 7-8: INTERNET AND WORLD WIDE WEB

Network is a set of devices (often referred to as nodes) connected by communication links in order to communicate and share resources.

Computer networks may be classified according to the scale:-

1.       Local area network (LAN)

2.       Metropolitan area network (MAN)

3.       Wide area network (WAN)

Local area network (LAN)

LAN connects networking devices with in short span of area, i.e. small offices, home, nternet cafes etc.

Spanned inside a building and operated under single administrative system

It uses TCP/IP network protocol for communication between computers

LAN provides a useful way of sharing the resources between end users. The resources such as printers, file servers, scanners, and internet are easily sharable among computers

LAN can be wired,wireless, or in both forms at once.

          

Metropolitan area network (MAN)

MAN generally expands throughout a city such as cable TV network

Metro Ethernet is a service which is provided by ISPs

This service enables its users to expand their Local Area Networks.

For example, MAN can help an organization to connect all of its offices in a city.

MAN works in between Local Area Network and Wide Area Network

MAN provides uplink for LANs to WANs or internet

 

Wide area network (WAN)

WAN connection between computers over large geographical areas that may comprise a country, a continent, or even the whole world

Dedicated transoceanic cabling or satellite uplinks may be used to connect this type of global network

These networks provide connectivity to MANs and LANs

The Internet itself is the biggest example of WAN

What is Internet

It is a Global network of computers, (servers or clients) to exchange information.

It is a "network of networks" that includes millions of  private and public, academic, business, and government networks (local or Global), linked by copper wires, wireless connections, and other technologies  

Intranet

Internal company network that uses Internet standards (HTML, HTTP & TCP/IP protocols) & software.

Accessed only by authorized persons, especially members or employees of the organization  

Extra-net

Extranet is an Intranet for outside authorized users using same internet technology. 

Website

Is a collection of an electronic pages that stores the information of a certain organization.

Type of website

Static : This is type of website that all user can see and interact with the same content in it.example www.suza.ac.tz

Dynamic:This is type of website that any user interact with different content in it.example Zalongwa.

WEB BROWSER
A web browser (commonly referred to as a browser) is a software application for retrieving, presenting and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier (URI/URL) that may be a web page, image, video or other piece of content. Hyperlinks present in resources enable users easily to navigate their browsers to related resources.
Although browsers are primarily intended to use the World Wide Web, they can also be used to access information provided by web servers in private networks or files in file systems.
The major web browsers are Firefox, Google Chrome, Internet Explorer/Microsoft Edge, Opera, and Safari.

Mozilla Firefox vs Internet Explorer

Everyone who’s been on the Internet knows what Internet Explorer is. Internet browsers are an essential part in fully utilizing the Internet to the fullest. But, there are also other options and one of them is Mozilla’s Firefox. There is a big difference though when it comes to popularity as Internet Explorer is still the most used browser in the world with Firefox as a distant second.
The main reason behind the popularity of Internet Explorer is its availability. It comes bundled with every version of Windows and users can simply update to new versions when they become available. Because Windows is the biggest operating system for personal computers, Internet Explorer already has such a huge advantage. Firefox comes preinstalled with certain Linux distributions but these are used on quite a small percentage of computers. If you want Firefox on Windows, you need to download an installer; commonly through Internet Explorer.
1. Internet Explorer is the most popular browser while Firefox is only second
2. Internet Explorer is bundled with Windows while Firefox is not
3. Internet Explorer is available only on Windows while Firefox is available for other operating systems
4. Internet Explorer is slow than Firefox
5. Internet Explorer is less secure than Firefox

Home Page

When you launch a Web browser, it automatically opens a new window with a default home page--usually Google.com or Bing.com--loaded and ready to go. You can set the home page to any website you prefer, however. Here's how to change the home page in Microsoft Internet Explorer, Google Chrome, and Mozilla Firefox

Change Your Internet Explorer Home Page

1. Click Tools, Internet options. Windows Vista/7 users may need to press the Alt key for the menu to appear

2. The Internet Options window will open. Click the General tab, and type in the address of the website you want as your start page under the 'Home page' heading.

3. Click Apply, OK to close the window.

Change Your Google Chrome Home Page

1. Click the wrench icon in the top-right corner of the browser.

2. Select Options

3. In the 'On startup' section, select Open the home page.

4. In the 'Home page' section, choose Open this page and type in the address of the website you would like as your start page.

5. The settings apply immediately. You may close the settings tab now.

Change Your Mozilla Firefox Home Page

1. Click the Firefox menu at the top-left portion of the browser.

2. Click the Options menu, and then Options.

3. The Options window will open. Go to the Startup section and select When Firefox starts: Show my home page.

4. In the Home Page field, type in the website address you want to use as your home page.

5. Click OK.

URL - Uniform Resource Locator

URL is the abbreviation of Uniform Resource Locator. It is the global address of documents and other resources on the World Wide Web. For example, www.webopedia.com is a URL. A URL is one type of Uniform Resource Identifier (URI); the generic term for all types of names and addresses that refer to objects on the World Wide Web.

PARTS OF A URL

The first part of the URL is called a protocol identifier and it indicates what protocol to use, and the second part is called a resource name and it specifies the IP address or the domain name where the resource is located. The protocol identifier and the resource name are separated by a colon and two forward slashes.

For example, the two URLs below point to two different files at the domain webopedia.com. The first specifies an executable file that should be fetched using the FTP protocol; the second specifies a Web page that should be fetched using the HTTP protocol:

ftp://www.webopedia.com/stuff.exe 
http://www.webopedia.com/index.html

INTERNET SERVICES

History of the world wide web 

The World Wide Web ("www" or simply the "web") is a global information medium which users can read and write via computers connected to the internet. The term is often mistakenly used as a synonym for the internet itself, but the web is a service that operates over the internet, just as e-mail also does. The history of the internet dates back significantly further than that of the world wide web.

Email 

Electronic mail, or email, is a method of exchanging digital messages between people using digital devices such as computers, tablets and mobile phones. Email first entered substantial use in the 1960s and by the mid-1970s had taken the form now recognised as email. Email operates across computer networks, which in the 2010s is primarily the Internet. Some early email systems required the author and the recipient to both be online at the same time, in common with instant messaging. Today's email systems are based on a store-and-forward model. Email servers accept, forward, deliver, and store messages. Neither the users nor their computers are required to be online simultaneously; they need to connect only briefly, typically to a mail server or a webmail interface, for as long as it takes to send or receive messages.

Originally an ASCII text-only communications medium, Internet email was extended by Multipurpose Internet Mail Extensions (MIME) to carry text in other character sets and multimedia content attachments. International email, with internationalized email addresses using UTF-8, has been standardized, but as of 2016 it has not been widely adopted.

The history of modern Internet email services reaches back to the early ARPANET, with standards for encoding email messages published as early as 1973 (RFC 561). An email message sent in the early 1970s looks very similar to a basic email sent today. Email played an important part in creating the Internet,and the conversion from ARPANET to the Internet in the early 1980s produced the core of the current services.

 Social network

A social network is a social structure made up of a set of social actors (such as individuals or organizations), sets of dyadic ties, and other social interactions between actors. The social network perspective provides a set of methods for analyzing the structure of whole social entities as well as a variety of theories explaining the patterns observed in these structures. The study of these structures uses social network analysis to identify local and global patterns, locate influential entities, and examine network dynamics.

Social networks and the analysis of them is an inherently interdisciplinary academic field which emerged from social psychology, sociology, statistics, and graph theory. Georg Simmel authored early structural theories in sociology emphasizing the dynamics of triads and "web of group affiliations". Jacob Moreno is credited with developing the first sociograms in the 1930s to study interpersonal relationships. These approaches were mathematically formalized in the 1950s and theories and methods of social networks became pervasive in the social and behavioral sciences by the 1980s. Social network analysis is now one of the major paradigms in contemporary sociology, and is also employed in a number of other social and formal sciences. Together with other complex networks, it forms part of the nascent field of network science.

 Surfing the Internet

Surfing the Internet' is not to be confused with the phrase 'browsing the Internet' which refers to exploring the web with a clear-cut objective but without any planned search strategies. Searching the web refers to exploring the Internet with a definite in both strategy and objective.

Surfing the Internet has been likened to the ironic term 'channel surfing', which is used to describe randomly changing TV channels. Its only relation to actual surfboarding has to do with the notion of 'going with flow' when surfing.

Web search engine

A web search engine is a software system that is designed to search for information on the World Wide Web. The search results are generally presented in a line of results often referred to as search engine results pages (SERPs). The information may be a mix of web pages, images, and other types of files. Some search engines also mine data available in databases or open directories. Unlike web directories, which are maintained only by human editors, search engines also maintain real-time information by running an algorithm on a web crawler.