Web UNIT 1

UNIT 1: Introduction to the Internet

The Internet

  • Definition: An interconnected network that connects people globally.

  • Structure: Composed of independently operated networks with no central control.

  • Connectivity: Emphasizes end-to-end connectivity across all systems.

  • Physical Layer: Uses underground wires to facilitate communication between computers.

  • Servers: Special computers directly connected to the Internet.

    • Store web pages as files on hard drives.

    • Each server has a unique IP address for identification.

History of the Internet

  • Founders: Developed by Bob Kahn and Vint Cerf during the 1970s.

  • Early Experiment: Originated from ARPANET - intended for secure communication for the U.S. Defense.

  • Public Access: The World Wide Web (WWW) was opened to the public on August 6, 1991.

How the Internet Works

  • Clients vs. Servers: Computers (clients) access the Internet via an Internet Service Provider.

  • Data Transmission: Information is broken into packets and then reassembled.

    • Routing: Handled by routers, which determine the best path for data packets.

    • Protocols: Transfer Control Protocol (TCP) ensures no packets are lost during transmission.

  • Message Transfer Steps:

    1. Computer1 sends a message to Computer2's IP.

    2. The message is subdivided into packets.

    3. Packets undergo transfer through the TCP.

    4. Packets arrive and are reassembled at Computer2.

Tim Berners-Lee: Father of the Internet

  • Contributions: Developed the WWW, HTTP (HyperText Transfer Protocol), HTML, and URLs between 1989-1991.

  • Background: Born in London, graduated in Physics from Oxford University in 1976.

  • Current Role: Director of the World Wide Web Consortium.

  • Co-founders Recognition: Vint Cerf is also heralded as an 'internet daddy'.

Uses of the Internet

  • E-mail: Electronic messaging service.

  • Web Chat: Real-time messaging applications.

  • World Wide Web (WWW): The primary information exchange service.

  • E-commerce: Facilitates online business transactions.

  • Internet Telephony & Video Conferencing: Allows real-time voice and video communication.

Advantages of the Internet

  • Information Access: Vast resources for research.

  • Entertainment: Online gaming, music, and streaming services.

  • News Updates: Real-time news on various subjects.

  • Online Shopping: E-commerce provides convenience.

Disadvantages of the Internet

  • Health Risks: Potential for addiction among youth.

  • Privacy Concerns: Risks of hacking and data breaches.

  • Reduced Interpersonal Interaction: Preference for online transactions limits face-to-face interactions.

What is the World Wide Web?

  • Definition: A collection of web pages stored on web servers and accessed via the Internet.

  • Content Types: Comprises text, images, audio, and video.

  • Access Mechanism: Utilizes web browsers and links (hyperlinks).

  • Web Page Addressing: Each web page has a unique URL.

Difference Between Internet and World Wide Web

  • Internet: A global network of computers facilitating communication, email, and chat.

  • World Wide Web: A service that runs on the Internet, consisting of numerous websites and web pages accessed through browsers.

Web 2.0

  • Definition: Introduced by Darcy DiNucci in 1999, emphasizes user-generated content and interoperability.

  • Characteristics:

    • Enhanced user interaction and collaboration.

    • Use of AJAX and JavaScript for dynamic content.

Web Browsers

  • Definition: Software for accessing the Web (e.g., Chrome, Firefox, Safari).

  • Purpose: To interpret HTML and display web pages.

  • Popular Web Browsers: Include Internet Explorer, Google Chrome, Mozilla Firefox, Safari, and many others.

Web Server Types

  • Definition: Computers that host and serve web pages.

  • Common Web Servers: Apache, IIS, lighttpd, Jigsaw, and Sun Java System Web Server.

Web Protocols

  • HTTP: Standard for web page transfers.

  • HTTPS: Secure version of HTTP to protect sensitive data.

  • FTP: For transferring files via the Internet.

Conclusion

  • Understanding basic concepts of the Internet, its workings, the technologies that support it, and its advantages and disadvantages is critical in navigating the modern digital landscape.