The Internet Phenomenon

When discussing the Internet, most folks limit themselves to the World Wide Web. However, there are many components that make up the Internet. For purposes of this book, I will discuss the three primary components most useful to DB2 professionals: the World Wide Web, Usenet Newsgroups, and mailing lists.

The World Wide Web

The World Wide Web (WWW) uses a graphical interface and hypertext protocol to display information in a point and click environment. Using a Web browser (such as Netscape Navigator or Microsoft Internet Explorer), you can navigate through the Internet, accessing Web pages and FTP and gopher sites. A vast array of multimedia information (text, audio, video, and more) can be accessed using the WWW.

Having secured access to a Web browser, the first thing to do is to access a Web page. Web sites on the Internet provide a simple address that lets users access their site. That address, known as a URL (or Uniform Resource Locator), can be fed into a Web browser, thereby providing access to the site. The address is always preceded by the following:

 http:// 

HTTP stands for HyperText Transfer Protocol, a communication protocol that understands that any document it retrieves contains information about future links referenced by the user . Of course, other Internet resources, such as gopher or ftp, can be accessed using a Web browser. For example, instead of typing http , the user can also specify the following:

ftp://	To access an FTP site
file://	To access a local (or networked) data file
gopher://	To access a gopher site
mailto://	To send mail
news://	To access Usenet Newsgroups

A Web page is a combination of text and graphics that provides hypertext links to other documents and services. The hypertext links are coded in the standard language known as HTML. An example showing my home page is depicted in Figure 17.1. The URL for this Web site is http://www.craigsmullins.com.

If you look closely, you can see the URL depicted in the address box in Figure 17.1.

A page is the basic unit of every Web site. A Web page contains text, links, and images, but can also contain forms, frames , and tables.

Text on most Web pages is formatted into multiple, layered headers and accompanying body text to help organize the information on the page. A link, sometimes referred to as a hyperlink, takes you to another page or to a graphic or other related file. Links can be textual or graphical. Textual links are underlined and in color . When you roll the cursor over a link it will change from an arrow to a pointing finger.

Forms are Web pages that have been organized using input boxes, pull-down lists, and radio buttons to enable easy data entry by users. Typically, forms are used to accept a user's demographic information or to enter credit card information when buying products over the Web. Frames allow several windows to be shown on a single Web page. The most common use is to display a Table of Contents in one frame while the user navigates through the Web site in another frame. Tables display information in formatted rows and columns .

Figure 17.1. The Craig S. Mullins home page. (http://www.craigsmullins.com)

After a Web page is accessed, hypertext links can be pointed to and clicked on leading the user through layers of information. The Web browser allows the user to navigate through pages and pages of useful information. The information can be printed, saved to disk, or simply browsed.

Usenet Newsgroups

A very fertile source of information on the Internet is found in various Usenet Newsgroups. Usenet, an abbreviation for User Network, is a large collection of discussion groups called newsgroups. Each newsgroup is a collection of articles pertaining to a single, predetermined topic. Newsgroup names usually reflect their focus. For example, comp.databases.ibm-db2 contains discussions about the DB2 family of products.

Using News Reader software, any Internet user can access a newsgroup and read the information contained therein. There are more than 30,000 different newsgroups available ”more than enough to satisfy anyone 's curiosity . Refer to Figure 17.2 for an example using the Forte Agent newsgroup reader to view messages posted to comp.databases.ibm-db2 .

Figure 17.2. A Newsgroup reader.

Mailing Lists

Mailing Lists are a sort of community bulletin board. You can think of mailing lists as equivalent to a mass mailing. There are thousands of mailing lists available on the Internet, and they operate using a list server. A list server is a program that automates the mailing list subscription requests and messages. The two most common list servers are Listserv and Majordomo. Listserv is also a common synonym for mailing list, but it is actually the name of a particular list server program.

Simply by subscribing to a mailing list, information is sent directly to your email in-box. After subscribing to a mailing list, articles will begin to arrive in your email box from a remote computer called a list server. The information that you will receive varies ”from news releases, to announcements, to questions, to answers. this information is very similar to the information contained in a CompuServe forum, except that it comes directly to you via email. Users can also respond to LISTSERV messages. Responses are sent back to the list server as email, and the list server sends the response out to all other members of the mailing list.

To subscribe to a mailing list, simply send an email to the appropriate subscription address requesting a subscription.

Using the Internet with DB2

There are two main reasons for DB2 professionals to use the Internet:

• To develop applications that allow for Web-based access to DB2 data

• To search for DB2 product, technical, and training information

Now take a look at ways of doing both of these.