Como a Internet chega na minha casa? - @Curso em Vídeo HTML5 e CSS3

Introduction to Web Development

Welcome and Course Overview

• The video welcomes viewers to a web development course focusing on HTML and CSS.

• A special message from Hostnet, the sponsor of the course, is introduced, highlighting their long-standing support for the channel.

Hostnet Services

• An overview of Hostnet's services is provided, including hosting and domain registration.

• The course will cover creating websites and deploying them online, noting that free options are limited.

• As students progress in their skills, they may require professional hosting services offered by Hostnet.

The History of the Internet

Origins During the Cold War

• The instructor aims to make a potentially dull topic engaging while discussing the internet's origins during a challenging historical period: the Cold War.

• The internet was developed as a response to military needs during this time of geopolitical tension between the United States and the Soviet Union.

Technological Competition

• Following World War II, both superpowers emerged strong but entered into a mental battle rather than direct conflict.

• In 1969, the Soviet Union launched Sputnik, marking a significant technological milestone that alarmed U.S. officials.

Development of ARPANET

Response to Technological Threat

• Sputnik's launch led to fears in America about Soviet technological superiority; thus, an agency called DARPA was established for military technology research.

• DARPA aimed to create backup systems for military data due to concerns over potential attacks on military bases.

Initial Network Creation

History of Computer Networking

Early Computers and Communication Challenges

• In the early 1970s, several universities had different types of computers, including SDS Sigma at UC Berkeley, SDS 90 at Stanford, IBM-360/75 in Los Angeles, and a military DEC PDP-10.

• The project aimed to establish communication between these computers for data backup and information exchange; however, they faced significant compatibility issues due to differing languages.

• Each computer brand used its own language, making it impossible for them to communicate directly (e.g., IBM could not talk to DEC or SDS).

Development of Network Protocols

• To address communication barriers, researchers developed the Network Control Protocol (NCP), which served as a common language for different systems.

• The analogy used was that if four people spoke different languages but all knew English, they could communicate effectively using English as a common language.

• NCP was primitive and inefficient; when one computer transmitted data, it halted the entire network until transmission was complete.

Growth of Networking Infrastructure

• By 1970, the network had expanded significantly with more points connected. However, by 1972 it became impractical to use NCP due to the growing number of connections.

• Researchers Robert Kahn and Vinton Cerf created the Transmission Control Protocol (TCP), which allowed multiple transmissions without halting the network.

Emergence of TCP/IP

• As networks grew larger, identifying machines became problematic. This led to the development of Internet Protocol (IP), allowing unique identification for each machine on a network.

• The combination of TCP and IP protocols formed what is now known as TCP/IP. This foundational protocol has evolved over time; currently in version six as of 2020.

Expansion Beyond Military Use

• By 1977, international communications were established with satellite links connecting universities across continents (e.g., US and London).

• As ARPANET grew beyond military control with various users from academia and small businesses emerging on the network.

Separation into Distinct Networks

• The military decided to separate their operations into MILNET while scientific institutions continued under NSFNET (National Science Foundation Network).

• Commercial networks also emerged during this period leading to interconnectivity among isolated networks seeking collaboration.

Birth of the Internet Concept

• The term "internetworking" was coined referring to interconnected networks that eventually simplified into "Internet."

• The modern internet evolved from ARPANET's initial framework designed during wartime for secure communications.

How Are Continents Connected?

The Nature of Connections

• The current state of global connectivity is characterized by continents being interconnected without issues, primarily through underwater cables rather than satellite communications.

• The internet is described as a vast network composed of multiple smaller networks, emphasizing its complexity and the origins of its terminology.

Data Transfer Mechanisms

• Various systems facilitate communication beyond coastal areas, including satellite systems and cellular networks, which are essential for data transfer inland.

• A scenario is presented where two computers (point A and point B) communicate; point A represents the user's computer while point B represents the server hosting content.

Client-Server Interaction

• When accessing media online (e.g., YouTube), the user's computer acts as a client requesting files from servers that store these resources.

• An example illustrates how a user requests an image from a server, highlighting the process involved in retrieving digital content over the internet.

Understanding TCP/IP Protocol

• The TCP/IP protocol plays a crucial role in breaking down large messages into smaller packets for efficient transmission across different routes.

• Packets may arrive out of order or via various paths; however, they are reassembled at their destination to reconstruct the original message accurately.

Visualizing Data Transmission

• Users may experience delays when loading heavy images due to packet arrival times; this phenomenon reflects how data is transmitted over the internet.

• A recommendation is made to watch a documentary that visually explains how data travels through networks and undersea cables, enhancing understanding of internet mechanics.

Exploring Underwater Cables and Data Centers

Insights from Recommended Documentary

• Viewers are encouraged to check out an informative video that discusses how data is organized into bits and bytes during transmission.

• The documentary features simulations showing email sending processes and visualizes data pathways through various infrastructures like data centers.

Infrastructure Overview

• It highlights visits to underwater cable installations, showcasing fiber optic technology used for global connectivity.

• Notable scenes include representations of potential disruptions (like marine life interacting with cables), illustrating vulnerabilities in infrastructure.

Conclusion on Learning Resources

Understanding the Evolution of the Internet

Introduction to Communication Channels

• The speaker introduces a Telegram channel as an effective way to stay updated with course content, likening it to WhatsApp but more efficient for notifications.

• Emphasizes the importance of staying informed about new video releases and course updates through this platform.

The Early Days of the Internet

• Describes the primitive state of the internet in its early days, characterized by a black screen with green text and basic navigation protocols like Gopher.

• Highlights that users navigated using keyboard commands rather than a mouse, illustrating how different browsing was compared to modern standards.

Graphics and Protocol Development

• Discusses how images were downloaded separately in early web experiences, contrasting it with today's integrated multimedia approach.

• Mentions that Gopher protocol allowed users to access text-based links using keyboard arrows, showcasing early internet navigation methods.

Tim Berners-Lee's Contributions

• Introduces Tim Berners-Lee's pivotal role in developing web technology in 1993, including his work on hypertext links which evolved into HTTP.

• Explains that HTTP (Hypertext Transfer Protocol) became foundational for web communication and is still used today.

HTML and World Wide Web Creation

• Details Berners-Lee's creation of HTML (Hypertext Markup Language), which allows for structured documents on the web through markup tags.

• Clarifies that "World Wide Web" refers to a system built upon these technologies, enabling interconnected documents across networks.

Browsers: The Gateway to Accessing Information

• Discusses the development of browsers, specifically Mosaic as one of the first compatible browsers created by Marc Andreessen.

• Notes that this browser facilitated access to HTML content and played a crucial role in popularizing web usage.

Distinguishing Between Internet and World Wide Web

• Differentiates between 'Internet' as a vast network connecting various servers and 'World Wide Web' as a subset focused on HTTP services.

• Explains specialized servers within the internet such as FTP for file transfers and SMTP/POP3/IMAP for email communications.

Conclusion: Understanding WWW Structure

• Concludes by reiterating that WWW is essentially a sub-network within the broader internet framework dedicated to serving HTTP requests.

Understanding HTTP and HTML in Web Development

The Role of HTTP and HTML

• Internet sub-networks can communicate using various protocols, including HTTP for FTP servers and email access. This highlights the versatility of web technologies.

• HTTP is specialized for hypertext, which is crucial for web development focused on creating hypertext content. Understanding this protocol is foundational to the discipline.

• The construction and delivery of HTML documents are essential topics; the next lesson will cover how HTML reaches a user's machine from a server.

Evolution of the Internet

• The internet has evolved significantly since its inception, showcasing dynamic capabilities that were not present in earlier versions.

• Users can now engage with multimedia content such as videos, images, and social media directly through their browsers, illustrating the advancements made possible by Tim Berners-Lee's contributions.

Importance of World Wide Web

• The emergence of the World Wide Web around 1993/1994 was pivotal in transforming the internet into what it is today. It enabled rich content creation and sharing.

• Learning about HTML and CSS is essential for producing modern web content; viewers are encouraged to actively participate in learning through practical exercises.

Practical Learning Approach

• Viewers should keep a notebook handy during lessons to jot down important information and practice coding as instructed throughout the video series.

• Future lessons will explain how clients interact with servers to retrieve HTML documents, emphasizing how these documents transform into visual websites.