CS511 Handouts

CS511 HANDOUTS · LESSON# 1 – INTRODUCTION · LESSON# 2 – ECOSYSTEM OF WEB · A Complicated Ecosystem

As visualized in following figure , web development can also be understood as an ecosystem, one that builds on existing technologies (URL, DNS, and Internet), and contributes new protocols and standards (HTTP, HTML, and JavaScript) that facilitate client-server interactions. As this ecosystem matures, new client and server technologies, frameworks, and platforms continue to be developed in support of the web (PHP, jQuery, Bootstrap, etc.).

The model shows web-development as a three-storey building. Each floor depicts several aspects of web development with an illustration. Ground floor shows Servers, Configuration, Networks, and Protocols which are the basic building blocks. Middle floor shows different languages which are a part of web development, like CSS, HTML, PHP, Javascript, databases, APIs, and Tools. Top level shows advanced concepts like Design, Search, Integration, Frameworks, and Security.

A Short History of the Internet

Telephone Network

..Telephone networks provides the basic infrastructure.

Packet Networks ARPANET (Advanced research projects agency networks ) (1969)

..This early ARPANET network was funded and controlled by the United States government, and was used exclusively for academic and scientific purposes. The early network started small, with just a handful of connected university campuses and research institutions and companies in 1969.

X.25 (1974)

..At the same time, alternative networks were created like X.25 in 1974, which allowed (and encouraged) business use.

USENET (1979)

..USENET, built in 1979, had fewer restrictions still, and as a result grew quickly to 550 connected machines by 1981. It focuses on unrestricted access.

TCP/IP (1983)  INTERNET

..To promote the growth and unification of the disparate networks, a suite of protocols was invented to unify the networks. A protocol is the name given to a formal set of publicly available rules that manage data exchange between two points. Communications protocols allow any two computers to talk to one another, so long as they implement the protocol. By 1981, protocols for the Internet were published and ready for use. New networks built in the United States began to adopt the TCP/IP (Transmission Control Protocol/Internet Protocol) communication model.

Internet vs. (World Wide) Web

“Internet is the hardware part - it is a collection of computer networks connected through either copper wires, fiber-optic cables or wireless connections whereas, the World Wide Web can be termed as the software part – it is a collection of web pages connected through hyperlinks and URLs. In short, the World Wide Web is one of the services provided by the Internet. Other services over the Internet include e-mail, chat and file transfer services. All of these services can be provided to consumers for use by businesses or government or by individuals creating their own networks or platforms.”

The Birth of the Web (1990)

The British Tim Berners-Lee (now Sir Tim Berners-Lee), who, along with the Belgian Robert Cailliau, published a proposal in 1990 for a hypertext system while both were working at CERN (European Organization for Nuclear Research) in Switzerland. Shortly thereafter Berners-Lee developed the main features of the web. This early web incorporated the following essential elements that are still the core features of the web today:

A Uniform Resource Locator (URL) to uniquely identify a resource on the WWW. The Hypertext Transfer Protocol (HTTP) to describe how requests and responses operate. A software program (later called web server software) that can respond to HTTP requests. Hypertext Markup Language (HTML) to publish documents. A program (later called a browser) that can make HTTP requests to URLs and that can display the HTML it receives.

Growth of Internet

Number of Internet Hosts increases tremendously between 2000 to 2015 for a figure of 1 billion hosts.