The Internet is a network of interconnected computers. The term Protocol refers to the mode of communication. Such as FTP, WWW, E-mail etc. These are all various protocols. The World Wide Web (WWW or "the Web") is just one of the protocols.

The Internet in many forms: PCs, Web TV, Cell phones& PDAs

Various authoring tools: free tools on the web

Role of media:
Radio -> TV -> Web
Such as with NBC over the years.

Uses of multimedia:

Types of sites:

Graphics Designer - Makes decisions about the visual elements on a page. The images, colors, layout, etc. Knowledge of Photoshop or an image editor is a must for a graphics designer. Download speed is an issue when dealing with media elements.

Interface Designer - Decides how the page works. Designs buttons, links, navigation, etc. Usually the graphics designer also does the interface design.

Information Designer - Makes the charts and diagrams when making a site. They help in the overall concept of the site.

HTML production - Turning the content into a web page. Knowledge of HTML tags is useful (especially for debugging a page).

Programmers - They typically do scripting and interactive material for a site.

Multimedia - Sounds, video, images. Macromedia Flash lets you make rich interactive content for your site. We'll learn how to use images, sounds, video on a web site. With Flash, we'll make some animation and interactive enhancements for a site.

HTML is the language of the web. HyperText Markup Language. Pages are written in plain text, with various commands (called tags) that the web browser will use to format the text, images, or other elements on a page.

Style Sheets - They let you define your own kind of tag, or modify an existing tag. They are useful for defining page properties. For example, in Cascading Style Sheets, if you wanted all your pages with a uniform background. You would setup a background CSS property for the background and store this in a file. All your pages would refer to this file. Now if you decided to the change the backgrounds on all these pages, you just reference 1 file and the pages instantly update.

DHTML - The D stands for Dynamic. This lets you modify a page's properties without the need to reload the page. If you ever saw an image floating down a page, such as a snow flake drifting on a page, DHTML allows that to be done. Typically a script is changing some property of an image to make this happen.

Javascript - This is a special language for a browser to do calculations and various manipulations to a page. This is not the same as Java.

Java is a programming language. Java allows you to create Java Applets for use on a site. These are little programs that run in your web browser.

CGI Programming - Common Gateway Interface. These are programs that run on a server. They interact with a client (typically your web browser). They allow for pages to be built on the fly. Such as a web counter is a CGI script that creates an image of the current visitor count. We will talk about CGI later on in the term and we'll learn how to make a form on a page mail information to the owner of a site.

XML (eXtensible Markup Language) - You can place data in a page with tags. So for example a phone number could have a <phonenum> tag. Different applications can pick out the parts that they need. For example a page can have a person's name & phone number. Depending on the application that views it, it knows what type of data it has. So for example, a program can dial the number.

Pages on the Web are linked. So one page can refer to another page. This term for linked information is called Hypertext. When you see a web page starting with HTTP:// this specifies to use the Hypertext Transfer Protocol.

A server serves information. So a web server (HTTP server) serves web pages. A client requests the information from the server. In the web, a web browser (such as Netscape or Internet Explorer) request the information. Any computer can be a server, just as long as it can meet the demands.

Every computer on the Internet has an IP address (Internet Protocol). You can see the IP address of your computer. This number is the reference to your computer. If you were to run a server on it, other people could connect to you.

See graphically where in the world a computer is.

However IP addresses are sort of complicated to remember. To help with this, you enter in the name of a site. Such as www.yahoo.com instead of 216.109.118.77 . A Domain Name System lets you enter in a sites name and then looks up the IP address. Ultimately all sites are references by IPs.

URL (Uniform Resource Location) is the address to a page on a site.
Lets look at the following URL:
http://www.lawrencegoetz.com/programs/free.html

http:// - this is the protocol
www.lawrencegoetz.com - this is the domain name of the site.
programs - this is directory
free.html - this is the file name that is being requested

Domain names are read from right to left.

com is the domain type
lawrencegoetz is the organization name
www is the machine name

http://www.lawrencegoetz.com/
In this case there is no directory or file name requested. The server sees the / at the end of the URL. So it looks for files in the root (main) directory. It will load a default file. Typically this file is called index.html or index.htm. However some servers use default.html, default.htm, and other standards.

A page is actual plain text. It's the browser that reads the tags to formatting of text, insert images, etc. If you have a web page that contains an image, you need to upload the image too. The page may look like one whole document, however the items in the page are not embedded but are referenced by the page.

When a web page contains an image, the image tag generally tells the browser how large the image is. This helps the web page display faster. This is because the text can be layed out to fit near the image. If the browser doesn't know the image size, it will need to start downloading the image, before the remainder of the page can display.

TCP/IP standard for Transmission Control Protocol over Internet Protocol. TCP allows various computers to talk over the Internet. IP specifies how the data is routed. For example Email or a web page is transferred and split into IP packets. The advantages are that they have error recovery by requesting the packets over again. The packets can take various routes over the network, and can appear out of sequence. Headers give control information. Such as packet number, source, destination, etc.

Packet Switching - This reassembles the packets into the correct order to form the data that was sent.

TCPDump and packet sniffing

Antivirus and firewalls
ports and connections
block port 80 stops web

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