World Wide Web

The World Wide Web is a system of interlinked hypertext documents accessed via the Internet The World Wide Web is a system of interlinked hypertext documents accessed via the Internet With a web browser, one can view Web pages that may contain text, images, videos, and other multimedia and navigate between them using hyperlinks. With a web browser, one can view Web pages that may contain text, images, videos, and other multimedia and navigate between them using hyperlinks.

World Wide Web These documents are hypertext documents which can contain built-in applications, links to databases, text, pictures, sounds, graphics, animations and movies. These documents are hypertext documents which can contain built-in applications, links to databases, text, pictures, sounds, graphics, animations and movies.

World Wide Web (www) These documents are written in a Web authoring language. These documents are written in a Web authoring language. The simplest language is called HTML (HyperText Markup Language). The documents are therefore saved as HTML type (index.html) The simplest language is called HTML (HyperText Markup Language). The documents are therefore saved as HTML type (index.html) The World Wide Web also uses a set of rules (protocol) that govern how documents written in HTML are displayed. This protocol is the HyperText Transfer Protocol (HTTP) The World Wide Web also uses a set of rules (protocol) that govern how documents written in HTML are displayed. This protocol is the HyperText Transfer Protocol (HTTP)

Browsers A turning point for the World Wide Web began with the introduction of the Mosaic web browser in 1993, a graphical browser developed by a team at the National Center for Supercomputing Applications at the University of Illinois at Urbana- Champaign. A turning point for the World Wide Web began with the introduction of the Mosaic web browser in 1993, a graphical browser developed by a team at the National Center for Supercomputing Applications at the University of Illinois at Urbana- Champaign. This allowed the distribution of images and the standard text-only format from previous browsers. This allowed the distribution of images and the standard text-only format from previous browsers.

Protocols The computers that run and are attached to the internet must follow a set of rules of communication so they can exchange information. The computers that run and are attached to the internet must follow a set of rules of communication so they can exchange information. These rules are called protocols, which essentially set the standard for computer communication. These rules are called protocols, which essentially set the standard for computer communication. Protocols may be found in software and/or hardware. Protocols may be found in software and/or hardware.

URLs URL Definition: URL Definition: A URL (Uniform Resource Locator) is defined as the absolute address of a web page or web resource on the Internet. A URL (Uniform Resource Locator) is defined as the absolute address of a web page or web resource on the Internet.

URLs URLs can be divided into three main parts URLs can be divided into three main parts PROTOCOL + DOMAIN NAME + PATH or FILEPROTOCOL + DOMAIN NAME + PATH or FILE Example:Example: In this example we have the following: In this example we have the following: Protocol: HTTP Protocol: HTTP Domain Name: globeandmail.com (the www is assumed) Domain Name: globeandmail.com (the www is assumed) Path or File: index.html Path or File: index.html

Domain Name System

Domain Name What is a Domain Name: What is a Domain Name: strings of letters and numbers (separated by periods) that are used to name organizations and computers and addresses on the internetstrings of letters and numbers (separated by periods) that are used to name organizations and computers and addresses on the internet a unique, case-insensitive, name, consisting of a string made up of alphanumeric characters and dashes separated by periods.a unique, case-insensitive, name, consisting of a string made up of alphanumeric characters and dashes separated by periods.

Domain Names The Domain Name System maps to IP numbers and other information; an identifier of a computer or site on the Internet. The Domain Name System maps to IP numbers and other information; an identifier of a computer or site on the Internet. IP Address are unique number (like telephone numbers) that are assigned to computers or devices on the network or internet. IP Address are unique number (like telephone numbers) that are assigned to computers or devices on the network or internet. The Domain Name System transfers the Domain Name to the correct IP Address so that the Domain Name can be found on the internet The Domain Name System transfers the Domain Name to the correct IP Address so that the Domain Name can be found on the internet

Domain Name System Within a domain name, there are various levels. Within a domain name, there are various levels. Example 1: 1: com is the Top Level com is the Top Level globeandmail is the Second Level globeandmail is the Second Level Example2: com is the Top Level com is the Top Level globeandmail is the Second Level globeandmail is the Second Level invest is the subdomain invest is the subdomain

Subdomains Subdomains are created by the owner of a domain to create more address on the one address. Subdomains are created by the owner of a domain to create more address on the one address. For example, may want separate sections for For example, may want separate sections forwww.globeandmail.com Autos, Investing, Entertainment and sportsAutos, Investing, Entertainment and sports Rather than having for different domains, they will create subdomains as: Rather than having for different domains, they will create subdomains as: autos.globeandmail.com, investing.globeandmail.com and so on.autos.globeandmail.com, investing.globeandmail.com and so on.

Common Protocols TCP/IP – used to connect to a network, the Transmission Control Protocol/Internet Protocol is used for packet distribution, to acquire an Internet Protocol Address (IP Address) TCP/IP – used to connect to a network, the Transmission Control Protocol/Internet Protocol is used for packet distribution, to acquire an Internet Protocol Address (IP Address) HTTP – the Hyper Text Transfer Protocol is a request/response protocol between the client and the server in requesting web documents HTTP – the Hyper Text Transfer Protocol is a request/response protocol between the client and the server in requesting web documents

Common Protocols FTP – the File Transfer Protocol is used to exchange (send and receive) documents over a network and to manipulate documents residing on a server FTP – the File Transfer Protocol is used to exchange (send and receive) documents over a network and to manipulate documents residing on a server SMTP – Simple Mail Transfer Protocol is used to set the guidelines that computers must follow to send and receive s SMTP – Simple Mail Transfer Protocol is used to set the guidelines that computers must follow to send and receive s