A software program that displays banners or pop-up windows containing commercial advertising. Adware typically appears on your monitor when you view a web site, preview a software program prior to purchase or use "sponsored" software that is available for free, but with the ads embedded in it. The justification for adware is that it helps recover programming development costs and holds down prices for users. Some adware, however, does more than display ads; it can track your navigation of the Internet and pass the information on to others without your knowledge. Used in this way, adware falls into a category of malicious software called spyware.

American Standard Code for Information Interchange (ASCII)

A computer language developed by the American National Standards Institute to define how computers write and read data. ASCII (pronounced ASKee) is commonly used to save text files that don't contain complicated formatting. It consists of a 128 characters -- letters, numbers, punctuation, and control codes (such as a character that marks the end of a line). Each letter or other character is represented by a number: an uppercase "A," for example, is represented by the number 65; a lowercase "z," by 122. Most computer operating systems use the ASCII standard, except for Windows NT, which uses the larger and newer Unicode standard.


Anchors are the same as hyperlinks (also called hypertext links)—the underlined words or phrases you click when viewing a web site in order to jump to another spot within the site or to a completely different site. The word "anchor" is used less often than "hyperlink," but it does maintain the seafaring theme of navigating and surfing the Internet.

Anonymous File Transfer Protocol (Anonymous FTP)

Part of the Internet's appeal is the huge variety of information (in the form of individual "files") that can be accessed on your personal computer. FTP is the near-universal computer program that makes this happen by connecting your computer with another computer (a server). The server delivers, or "serves," the appropriate file. Anonymous FTP is a form of FTP that allows anyone to download files from a properly configured server. This lets a user without a password-protected FTP account to access files by entering the username, "anonymous," along with his or her own email address as a password.

Application (Applet)

These terms all refer to simple, single-function programs that are often included along with a larger software product. Programs such as Windows Calculator, File Manager, and Notepad are examples.

Asynchronous Transfer Mode (ATM)

No, it's not the bank machine that spits out cash; this ATM is a computer protocol used for transmitting data. Specifically, it's a standard packet switching protocol -- meaning that it moves data via routes shared with other traffic, as opposed to circuit switching, which moves data between computers on designated "private" lines. The ATM protocol uses 53-byte cells, each consisting of a 5-byte address header and 48 bytes of related data. These short, standardized cells are processed very quickly at data transmission speeds over 600 mbps. ATM can support many uses, including voice, graphics, data, and full-motion video. It also allows telephone and cable TV companies to dynamically assign bandwidth to individual customers.

Any file -- a text document, photograph, graphic image, audio or video file -- that is transmitted along with an email message. Attachments are linked to your email in a way that allows them to remain as separate entities with all their characteristics intact; you can save them on your personal computer. Many email packages use MIME encoding to attach files.

Audio/Video Interleave (AVI)

When you see a video clip on your PC, there's a good chance that it's an AVI file. AVI is the file format used by Microsoft's Video for Windows, one of three video technologies used on personal computers. (The others are MPEG and QuickTime.) In AVI, picture and sound elements are interleaved -- arranged so that audio and video files are stored in alternating chunks -- which enhances their performance. The result: the video and audio match up.