Hypermedia

Most Web navigation is done by clicking text-basedlinks that open new pages in a Web browser. These links, which are often blue and underlined, are referred to as hypertext, since they allow the user to jump from page to page. Hypermedia is an extension of hypertext that allows images, movies, and Flashanimations to be linked to other content.

The most common type of hypermedia is an image link. Photos or graphics on the Web are often linked to other pages. For example, clicking a small "thumbnail" image may open a larger version of the picture in a new window. Clicking a promotional graphic may direct you to an advertiser's website. Flash animations and videos can also be turned into hyperlinks by embedding one or more links that appear during playback.

You can tell if an image or video is a hyperlink by moving the cursor over it. If the cursor changes into a small hand, that means the image or video is linked to another page. Clicking the text, image, or video will open up a new location in your Web browser. Therefore, you should only click a hypertext or hypermedia link when you are ready to leave the current page. If you want to open the link in a new window, you can usually right click the link and select "Open Link in New Window."

Hypertext

Hypertext is text that links to other information. By clicking on a link in a hypertext document, a user can quickly jump to different content. Though hypertext is usually associated with Web pages, the technology has been around since the 1960s. Software programs that include dictionaries and encyclopedias have long used hypertext in their definitions so that readers can quickly find out more about specific words or topics. Apple Computer's HyperCard program also used hypertext, which allowed users to create multi-linked databases. Today, the Web is where hypertext reigns, where nearly every page includes links to other pages and both text and images can be used as links to more content.

Fiber-Optic Cable

his is a cable made up of super-thin filaments of glass or other transparent materials that can carry beams of light. Because a fiber-optic cable is light-based, data can be sent through it at the speed of light. Using a laser transmitter that encodes frequency signals into pulses of light, ones and zeros are sent through the cable. The receiving end of the transmission translates the light signals back into data which can be read by a computer.

Because fiber-optics are based entirely on beams of light, they are less susceptible to noise and interference than than other data-transfer mediums such as copper wires or telephone lines. However, the cables are fragile and are usually placed underground, which makes them difficult and expensive to install. Some fiber-optic cables are installed above ground, but if they break, they often need to be completely replaced, which is not cheap. While copper wires can be spliced and mended as many times as needed, it is much harder to fix glass fiber-optic cables.

URL

Stands for "Uniform Resource Locator." A URL is the address of a specific Web site or file on the Internet. It cannot have spaces or certain other characters and uses forward slashes to denote different directories. Some examples of URLs are http://www.cnet.com/, http://web.mit.edu/, and ftp://info.apple.com/. As you can see, not all URLs begin with "http". The first part of a URL indicates what kind of resource it is addressing. Here is a list of the different resource prefixes:

• http - a hypertext directory or document (such as a Web page)
• ftp - a directory of files or an actual file available to download
• gopher - a gopher document or menu
• telnet - a Unix-based computer system that you can log into
• news - a newsgroup
• WAIS - a database or document on a Wide Area Information Search database
• file - a file located on your hard drive or some other local drive

The second part of a URL (after the "://") contains the address of the computer being located as well as the path to the file. For example, in "http://www.cnet.com/Content/Reports/index.html," "www.cnet.com" is the address or domain name of the host computer and "/Content/Reports/index.html" is the path to the file. When a address ends with a slash and not something like ".html" or ".php," the Web server typically defaults to a file in the current directory named "index.html," "index.htm," or "index.php." So, if you type in "http://www.apple.com/" and "http://www.apple.com/index.html," you should get the same page. Go ahead and try it if you have nothing better to do.

Blog

Short for "Web Log," this term refers to a list of journal entries posted on a Web page. Anybody who knows how to create and publish a Web page can publish their own blog. Some Web hosts have made it even easier by creating an interface where users can simply type a text entry and hit "publish" to publish their blog.

Because of the simplicity of creating a blog, many people (often young kids and adults) have found a new presence on the Web. Instead of writing confidential entries in a book that no one is supposed to see, people now can share their personal feelings and experiences with thousands of people around the world. Blogs are typically updated daily, monthly, or anywhere in between. "Blog" may also be used as a verb, as in "Wow, Matt sure blogged a lot last week."

Applet

This a Java program that can be embedded in a Web page. The difference between a standard Java application and a Java applet is that an applet can't access system resources on the local computer. System files and serial devices (modems, printers, scanners, etc.) cannot be called or used by the applet. This is for security reasons -- nobody wants their system wiped out by a malicious applet on some wacko's Web site. Applets have helped make the Web more dynamic and entertaining and have given a helpful boost to the Java programming language

Bit

The computer term "bit" comes from the phrase "Binary DigIT," which is different than that thing you put around a horse's mouth. A bit is a single digit number in base-2 (a zero or a one) and is the smallest unit of computer data. A full page of text is composed of about 16,000 bits.

It is important not to confuse bits with bytes. Both are used to measure amounts of data, but it takes eight bits to make one byte. The most common area where bits are used intstead of bytes is in measuring bandwidth (in bits per second). Why? Probably because it makes your Internet connection sound faster than it really is.