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What is the Internet?
- The Internet is a global Wide Area Network (WAN).
- A Network is a group of interconnected devices.
- A Wide Area Network (WAN) is a network that covers a large area.
- A Local Area Network (LAN) is a network that covers a small area.
What are the main advantages of the Internet?
- Communication : Electronic mail (Email) and social media.
- Education : search engines and webpages.
- Entertainment : online games and online media.
- Online services : online shopping and online banking.
What are the main disadvantages of the Internet?
- Threat to personal information : possible loss of name, address, credit card number,...
- Spamming : unwanted Emails that serve no purpose.
- Cybercrime : malware, ransomware, stealing of identities,...
- Virus attacks : cause a system to crash and may delete important data.
History of the Internet
- In the 1950s, the United States Defense Department formed the Advanced Research Projects Agency (ARPA) with the purpose of developing technology.
- ARPA’s scientists could not easily communicate or share information, so they created a network of computers, which they called ARPAnet.
- In the 1970s, the TCP/IP protocol was developed, this protocol allowed the separate networks to communicate with each other.
- The joining of these networks created a huge WAN which came to be known as the Internet.
The World Wide Web (WWW)
What is the World Wide Web (WWW)?
- The World Wide Web (WWW) is a collection of different websites that can be accessed through a web browser.
- A website is a group of web pages hosted on one web server.
- A web server is an Internet server that serves web pages to the web browser.
- A web browser is an application that displays web pages.
What is the difference between the World Wide Web (WWW) and the Internet?
- The Internet is a global WAN, and the WWW is an Internet service.
How the World Wide Web (WWW) works?
- When a user makes a request over the Internet, the web browser sends this request to a web server, and the web server accepts and responds to it by storing and transferring web pages to the web browser.
How are web pages transferred from servers to clients?
- Any resource connected to the WWW is identified by its Uniform Resource Locator (URL).
- A Uniform Resource Locator (URL) is the address of a WWW page.
- Example : http://www.example.com/...
- When the URL of a web page is identified, a protocol called Hyper Text Transfer Protocol (HTTP) sends a command to the web server.
- Hyper Text Transfer Protocol (HTTP) is a protocol which enables communication between web clients and web servers.
- Once the web server has transmitted the requested page, the web page can be displayed with Hyper Text Markup Language (HTML).
- Hypertext Markup Language (HTML) is the standard language for creating and displaying web pages.
History of the World Wide Web (WWW)
- In 1990, the WWW was invented by Tim Berners-Lee.
- He created three technologies (HTML, URL and HTTP), which allowed to use the Internet to link one document directly to another.
What is needed to connect to the Internet?
- Internet Service Provider (ISP) : a business that provides a connection to the Internet.
- Modem : a piece of hardware that allows a device to connect to the Internet over a telephone line.
- Router : a piece of hardware that allows several devices to connect to a single Internet connection.
Common methods of Internet connection
- Dial-up : an Internet connection which uses a telephone line and requires a landline.
- Digital Subscriber Line (DSL) : an Internet connection which uses a telephone line, but doesn’t require a landline.
- Cable TV : a wired Internet connection which uses Cable TV lines.
- Wi-Fi : a wireless Internet connection which uses radio waves.
- Satellite : a wireless Internet connection which uses satellites orbiting the Earth.
- 3G and 4G : wireless Internet connections which use cellular networks.
What is cloud computing?
- Cloud computing is the process of storing and using services online, rather than storing them locally on a device.
What are the main advantages of cloud computing?
- File storage : access files, documents and Emails from any device.
- File sharing : share files with several people at the same time.
- Backing up : protect your files.
What are the main disadvantages of cloud computing?
- Copyright : possible loss of legal rights.
- Security : vulnerability to security attacks.
- Storage : limited storage.