EXTRANET

Extranet is a controlled private network that allows access to partners, vendors and suppliers or an authorized set of customers – normally to a subset of the information accessible from an organization's intranet. 


An extranet is similar to a DMZ in that it provides access to needed services for authorised parties, without granting access to an organization's entire network. 

An extranet is a private network organization.

Advantages of Extranet:

• Exchange large volumes of data using Electronic Data Interchange (EDI)

• Share product catalogs exclusively with trade partners

• Collaborate with other companies on joint development efforts

• Jointly develop and use training programs with other companies

• Provide or access services provided by one company to a group of other companies, such as an online banking application managed by one company on behalf of affiliated banks

Disadvantages of Extranet:

• Extranets can be expensive to implement and maintain within an organization (e.g., hardware, software, employee training costs), if hosted internally rather than by an application service provider.

• Security of extranets can be a concern when hosting valuable or proprietary information.

INTRANET

Intranet is a private network accessible only to an organisation's staff. 

Generally a wide range of information and services from the organization's internal IT systems are available that would not be available to the public from the Internet. 

A company-wide intranet can constitute an important focal point of internal communication and collaboration, and provide a single starting point to access internal and external resources. 

In its simplest form an intranet is established with the technologies for local area networks (LANs) and wide area networks (WANs).

The benefits of Intranet are:

• Workforce productivity
• Time
• Communication
• Web publishing 
• Business operations and management
• Cost-effective
• Enhance collaboration
• Cross-platform capability
• Built for one audience
• Promote common corporate culture
• Immediate updates
• Supports a distributed computing architecture

INTERNET

Internet is the global system of interconnected computer networks that use the Internet protocol suite (TCP/IP) to link devices worldwide. 

It is a network of networks that consists of private, public, academic, business, and government networks of local to global scope, linked by a broad array of electronic, wireless, and optical networking technologies. 

The Internet carries an unlimited range of information resources and services, such as the inter-linked hypertext documents and applications of the World Wide Web (WWW), electronic mail, telephony, and file sharing.

World Wide Web

This NeXT Computer was used by Tim Berners-Lee at CERN and became the world's first Web server.

Many people use the terms Internet and World Wide Web, or just the Web, interchangeably, but the two terms are not synonymous. 

The World Wide Web is the primary application program that billions of people use on the Internet, and it has changed their lives immeasurably.However, the Internet provides many other services. 

The Web is a global set of documents, images and other resources, logically interrelated by hyperlinks and referenced with Uniform Resource Identifiers (URIs). URIs symbolically identify services, servers, and other databases, and the documents and resources that they can provide. 

Hypertext Transfer Protocol (HTTP) is the main access protocol of the World Wide Web. 

Web services also use HTTP to allow software systems to communicate in order to share and exchange business logic and data.

World Wide Web browser software, such as Microsoft's Internet Explorer/Edge, Mozilla Firefox, Opera, Apple's Safari, and Google Chrome, lets users navigate from one web page to another via hyperlinks embedded in the documents. 

These documents may also contain any combination of computer data, including graphics, sounds, text, video, multimedia and interactive content that runs while the user is interacting with the page. 

Client-side software can include animations, games, office applications and scientific demonstrations. Through keyword-driven Internet research using search engines like Yahoo!, Bing and Google, users worldwide have easy, instant access to a vast and diverse amount of online information. 

Compared to printed media, books, encyclopedias and traditional libraries, the World Wide Web has enabled the decentralization of information on a large scale.

COMPUTER SOFTWARE

• Computer software is a set of instructions for a computer to perform specific operations. 

• You need both hardware and software for a computer system to work.

• Software is capable of performing many tasks, as opposed to hardware which can only perform mechanical tasks that they are designed for. 

• Software provides the means for accomplishing many different tasks with the same basic hardware. 

Practical computer systems divide software systems into two major classes:

• System software: Helps run the computer hardware and computer system itself. System software includes operating systems, device drivers, diagnostic tools and more. System software is almost always pre-installed on your computer.

• Application software: Allows users to accomplish one or more tasks. It includes word processing, web browsing and almost any other task for which you might install software. (Some application software is pre-installed on most computer systems.)

  Software	Examples
  Antivirus	AVG, Housecall, McAfee, Norton
  Audio / Music program	iTunes, WinAmp
  Database	Access, MySQL, SQL
  Device drivers	Computer drivers
  E-mail	Outlook, Thunderbird
  Game	Madden NFL Football, Quake, World of Warcraft
  Internet browser	Firefox, Google Chrome, Internet Explorer
  Movie player	VLC, Windows Media Player
  Operating system	Android, iOS, Linux, macOS, Windows
  Photo / Graphics program	Adobe PhotoShop, CorelDRAW
  Presentation	PowerPoint
  Programming language	C++, HTML, Java, Perl, Visual Basic (VB)
  Simulation	Flight simulator, SimCity
  Spreadsheet	Excel
  Utility	Compression, Disk Cleanup, Encryption, Registry cleaner, Screen saver
  Word processor	Word

COMPUTER HARDWARE

DEFINITIONS

• A computer system consists of two major elements: hardware and software. 

• Computer hardware is the collection of all the parts you can physically touch. 

Example of hardware components are:

• the computer case
• keyboard
• monitor

  

  Hardware Component: Desktop Computer, mouse, motherboard and keyboard

  

  Basic Internal Hardware in Motherboard

  
  

  

  Hardware Component: Laptop