WWWW and The Internet Detailed Notes

Introduction to WWW and The Internet

• The Internet: An international network of connected computers designed to share information.

• World Wide Web (WWW): A subset of the internet consisting of interconnected documents and resources accessed via web browsers.

The Web and Internet

• Components of the Web:

  • URLs: Uniform Resource Locators that uniquely identify resources on the WWW.

  • HTTP: Defines how requests and responses operate between clients and servers.

  • Web Server Software: Responds to HTTP requests, serving web pages.

  • HTML: Hypertext Markup Language used to publish documents.

  • Browsers: Programs that make HTTP requests and display HTML content.

History of the Internet and the Web

• Milestones:

  • ARPANET (1969): First operational packet-switching network.

  • Domain Name System (1980s): A hierarchical naming system.

  • Tim Berners-Lee proposes the Web (1989) and publishes the first web page (1990).

  • Introduction of graphical browsers (e.g., Mosaic, 1993).

  • Launch of webmail services like HoTMaiL (1996).

  • Google search engine launched (1998).

How the Web Works

• Client-Server Architecture:

  • Clients make service requests, servers respond with the requested services.

Web Servers

• Definition: Hardware and software that utilizes HTTP and other protocols to respond to client requests.

• Functions:

  • Store, process, and deliver web pages to users.

• Examples: Microsoft IIS, Apache, Nginx.

Database Servers

• Function: Provides database services including storing and retrieving data via a Database Management System (DBMS).

• Interaction: Responds to requests from web servers or applications to perform data operations.

Communication Networks

• The internet consists of physical cables (copper and fiber optic) and relies on wireless connections like Wi-Fi.

Communication Protocols

• Definition: Standard mechanisms enabling different systems to communicate over a network.

• Key Protocols:

  • TCP/IP: Ensures reliable data transmission.

  • UDP: Allows faster, less reliable data transfer, often used in live broadcasts.

  • HTTP/HTTPS: Transfers web pages; HTTPS adds security measures.

Internet Protocol (IP) Address

• Public IP: Accessible over the internet, assigned by an ISP.

• Private IP: Used within a local network.

• Versions: IPv4 (32-bit) and IPv6 (128-bit).

Domain Name System (DNS)

• Function: Translates readable domain names into numerical IP addresses for accessing resources.

• Structure: Hierarchical and decentralized naming system.

Uniform Resource Locator (URL)

• Structure: Comprises scheme, authority, port, path, parameters, and anchor.

Domain Registrars

• Role: Manage domain name reservations on the internet.

• Functions: Include registration, renewal, transfer, WHOIS management, and DNS management.

Web Pages and Websites

• Web Page: Document written in HTML, which can include various types of content.

• Website: A collection of interconnected web pages; can be static (fixed content) or dynamic (real-time generated content).

Web Browsers

• Definition: Software that interprets and displays web pages, using HTTP to render content accessible to users.

• Popular Browsers: Chrome, Edge, Safari.

Responsive Web Design (RWD)

• Definition: A design approach that ensures compatibility across device sizes through adaptable layouts.

Frontend Development

• Focus: Concerns design aspects visible in the browser using HTML, CSS, JavaScript.

Backend Development

• Focus: Server-side applications, databases, and server software management.