ActiveX. A loosely defined set of technologies developed by Microsoft for sharing information among different applications. ActiveX is an outgrowth of two other Microsoft technologies called OLE (Object Linking and Embedding) and COM (Component Object Model). As a moniker, ActiveX can be very confusing because it applies to a whole set of COM-based technologies. Most people, however, think only of ActiveX controls, which represent a specific way of implementing ActiveX technologies. Affiliate programs. Affiliate programs allow Web sites who provide links to your site to receive payments or reciprocal advertising in exchange for promoting your Web site.
Audio/Video streaming. Audio/video streaming allows you to provide visitors to your site with a real-time sound or video experience.
Backbone. The network of connections and high-speed lines that forms the infrastructure of the Internet. An important consideration in choosing a Web site host is that host's proximity to the backbone. The less intermediate network distance between your provider and the backbone, the faster and more reliable your Web site will be.
Bandwidth. The amount of data that can be sent through a network connection, measured in bits per second (bps).
Banner ad. Banner ads are one of the primary methods of advertising on the Internet. They are usually small graphics with a very brief advertising message.
Bulletin board. A computerized version of the bulletin boards found in stores and other public places, where people can leave messages and advertise things they want to buy or sell.
Cache. Pronounced cash, a special high-speed storage mechanism. It can be either a reserved section of main memory or an independent high-speed storage device. Two types of caching are commonly used in personal computers: memory caching and disk caching. A memory cache, sometimes called a cache store or RAM cache, is a portion of memory made of high-speed static RAM (SRAM) instead of the slower and cheaper dynamic RAM (DRAM) used for main memory. Memory caching is effective because most programs access the same data or instructions over and over. By keeping as much of this information as possible in SRAM, the computer avoids accessing the slower DRAM. Some memory caches are built into the architecture of microprocessors. The Intel 80486 microprocessor, for example, contains an 8K memory cache, and the Pentium has a 16K cache. Such internal caches are often called Level 1 (L1) caches. Most modern PCs also come with external cache memory, called Level 2 (L2) caches. These caches sit between the CPU and the DRAM. Like L1 caches, L2 caches are composed of SRAM but they are much larger. Disk caching works under the same principle as memory caching, but instead of using high-speed SRAM, a disk cache uses conventional main memory. The most recently accessed data from the disk (as well as adjacent sectors) is stored in a memory buffer. When a program needs to access data from the disk, it first checks the disk cache to see if the data is there. Disk caching can dramatically improve the performance of applications, because accessing a byte of data in RAM can be thousands of times faster than accessing a byte on a hard disk. When data is found in the cache, it is called a cache hit, and the effectiveness of a cache is judged by its hit rate. Many cache systems use a technique known as smart caching, in which the system can recognize certain types of frequently used data. The strategies for determining which information should be kept in the cache constitute some of the more interesting problems in computer science.
CGI scripts. Programs that run on a Web server, in response to input from a browser. CGI scripts link the server and a program running on the system; for example, CGI scripts are used with interactive forms.
Chat room. A real-time electronic forum; a virtual room where visitors can meet others and share ideas on a particular subject. There are chat rooms on the Internet, Bulletin Board Services, and other online services.
Client-side. Occurring on the client side of a client-server system. For example, on the World Wide Web, JavaScript scripts are client-side because they are executed by your browser (the client). In contrast, CGI scripts are server-side because they run on the Web server. Java applets can be either server-side or client-side depending on which computer (the server or the client) executes them.
Common Gateway Interface (CGI). A set of rules that describe how a Web server communicates with another piece of software on the same machine, and how the other piece of software talks to the Web server. Usually, a CGI program is a small routine that takes data from a Web server and does something with it, like putting the content of a form into an email message, or turning the data into a database query.
DNS. Short for Domain Name System (or Service or Server), an Internet service that translates domain names into IP addresses. Because domain names are alphabetic, they're easier to remember. The Internet however, is really based on IP addresses. Every time you use a domain name, therefore, a DNS service must translate the name into the corresponding IP address. For example, the domain name www.example.com might translate to 198.105.232.4.
Domain name. A name that identifies one or more IP addresses. For example, the domain name microsoft.com represents about a dozen IP addresses. Domain names are used in URLs to identify particular Web pages. For example, in the URL http://www.pcwebopedia.com/index.html, the domain name is pcwebopedia.com. Because the Internet is based on IP addresses, not domain names, every Web server requires a Domain Name System (DNS) server to translate domain names into IP addresses. Domain name registration. Most Web designers will offer to register your chosen domain name for you. Alternatively, you can choose to register your domain name directly through InterNIC. Regardless of the method you choose there is a standard charge of $70 for registration.
DHTML. A combination of HTML enhancements, style sheets, and scripts that allow for animation, interactions, and dynamic updating of Web pages. Netscape Navigator and Internet Explorer have implemented Dynamic HTML with proprietary methods, but are expected to implement the W3C's Dynamic Object Model (DOM) in future versions.
E-commerce. Electronic commerce is the exchange of goods or services via the Internet. E-zine: Electronic magaZINE) A magazine or newsletter published online.
Flash. Animation software for Windows and the Mac from Macromedia. It is used to develop interactive graphics for Web sites as well as desktop presentations and games. Flash sequences on the Web are displayed by a Web browser plug-in and offline presentations are run by a Flash player that can be included on a floppy or CD-ROM.
FTP. Short for File Transfer Protocol, the protocol for exchanging files over the Internet. FTP works in the same way as HTTP for transferring Web pages from a server to a user's browser and SMTP for transferring electronic mail across the Internet in that, like these technologies, FTP uses the Internet's TCP/IP protocols to enable data transfer. FTP is most commonly used to download a file from a server using the Internet or to upload a file to a server (e.g., uploading a Web page file to a server).
GIF. (Graphics Interchange Format) A bit mapped graphics file format. It supports 8-bit color (256 colors) and compresses the files well. This translates into faster load times GIFs include a color table that includes the most representative 256 colors used. For example, a picture of the forest would include mostly greens. This method provides excellent realism in an 8-bit image.
Guestbook. A guestbook allows visitors to your site to give you their contact information (e.g. name, email or postal address, telephone number, business). You may be able to use this information to send email or direct marketing newsletters or simply collect marketing information about your customers.
HTML. (Hypertext Markup Language) The document format used on the World Wide Web. Web pages are built with HTML tags, or codes, embedded in the text. HTML defines the page layout, fonts and graphic elements as well as the hypertext links to other documents on the Web. Each link contains the URL, or address, of a Web page residing on the same server or any server worldwide, hence "World Wide" Web.
Hyperlink. A jump from text or from an image map to a page or other type of file on the World Wide Web. In World Wide Web pages, hyperlinks are the primary way to navigate between pages and among websites.
Internet. A global network connecting millions of computers. More than 100 countries are linked into exchanges of data, news and opinions. Unlike online services, which are centrally controlled, the Internet is decentralized by design. Each Internet computer, called a host, is independent. Its operators can choose which Internet services to use and which local services to make available to the global Internet community. Remarkably, this anarchy by design works exceedingly well. There are a variety of ways to access the Internet. Most online services, such as America Online, offer access to some Internet services. It is also possible to gain access through a commercial Internet Service Provider (ISP). The Internet is not synonymous with World Wide Web.
IP Address. (Internet Protocol Address) The standard way of identifying a computer that is connected to the Internet, much the way a telephone number identifies a telephone on a telephone network. The IP address is four numbers separated by periods, and each number is less than 256, for example, 192.200.44.69. Your system administrator or Internet service provider will assign your machine an IP address.
ISP. Short for Internet Service Provider, a company that provides access to the Internet. For a monthly fee, the service provider gives you a software package, username, password and access phone number. Equipped with a modem, you can then log on to the Internet and browse the World Wide Web, and send and receive e-mail.
Java. A high-level programming language developed by Sun Microsystems. Java was originally called OAK, and was designed for handheld devices and set-top boxes. Oak was unsuccessful so in 1995 Sun changed the name to Java and modified the language to take advantage of the burgeoning World Wide Web. Java is an object-oriented language similar to C++, but simplified to eliminate language features that cause common programming errors. Java source code files (files with a .java extension) are compiled into a format called byte code (files with a .class extension), which can then be executed by a Java interpreter. Compiled Java code can run on most computers because Java interpreters and runtime environments, known as Java Virtual Machines (VMs), exist for most operating systems, including UNIX, the Macintosh OS, and Windows. Byte code can also be converted directly into machine language instructions by a just-in-time compiler (JIT). Java is a general purpose programming language with a number of features that make the language well suited for use on the World Wide Web. Small Java applications are called Java applets and can be downloaded from a Web server and run on your computer by a Java-compatible Web browser, such as Netscape Navigator or Microsoft Internet Explorer.
JavaScript. A popular scripting language that is widely supported in Web browsers and other Web tools. It is easier to use than Java, but not as powerful and deals mainly with the elements on the Web page. On the client, JavaScript is maintained as source code embedded into an HTML document. On the server, it is compiled into byte code (intermediate language), similar to Java programs.
JPEG. (Joint Photographic Experts Group) Primarily used for still photographs. Pronounced "jay-peg." An ISO/ITU standard for compressing still images that is popular due to its high compression capability. Using discrete cosine transform, it provides lossy compression (you lose some data from the original image) with ratios up to 100:1 and higher. Again, this translates into faster load times.
Meta Tags. An HTML tag that identifies the contents of a Web page. Using a format, Meta tags contain such things as a general description of the page, keywords for search engines and copyright information.
NTSC. Short for National Television System Committee. The NTSC is responsible for setting television and video standards in the United States (in Europe and the rest of the world, the dominant television standards are PAL and SECAM). The NTSC standard for television defines a composite video signal with a refresh rate of 60 half-frames (interlaced) per second. Each frame contains 525 lines and can contain 16 million different colors. The NTSC standard is incompatible with most computer video standards, which generally use RGB video signals. However, you can insert special video adapters into your computer that convert NTSC signals into computer video signals and vice versa.
PHP. Self-referentially short for PHP: Hypertext Preprocessor, an open source, server-side, HTML embedded scripting language used to create dynamic Web pages. In an HTML document, PHP script (similar syntax to that of Perl or C ) is enclosed within special PHP tags. Because PHP is embedded within tags, the author can jump between HTML and PHP (similar to ASP and Cold Fusion) instead of having to rely on heavy amounts of code to output HTML. And, because PHP is executed on the server, the client cannot view the PHP code. PHP can perform any task that any CGI program can do, but its strength lies in its compatibility with many types of databases. Also, PHP can talk across networks using IMAP, SNMP, NNTP, POP3, or HTTP.
POP3. (Post Office Protocol 3) A standard mail server commonly used on the Internet. It provides a message store that holds incoming e-mail until users log on and downloads it. POP3 is a simple system with little selectivity. All pending messages and attachments are downloaded at the same time.
Portal. A Web "super site" that provides a variety of services including online advertising, Web searching, news, white and yellow pages directories, free e-mail, discussion groups, online shopping and links to other sites. If local, these portals offer community events and information.
QuickTime. Multimedia extensions to the Macintosh starting with System 7 that add sound and video capabilities. Apple also provides a QuickTime for Windows version for Windows - based PCs.
Resolution. The degree of sharpness of a displayed or printed character or image. On screen, resolution is expressed as a matrix of dots. For example, the VGA resolution of 640x480 means 640 dots (pixels) across each of the 480 lines. Sometimes the number of colors is added to the spec; for example, 640x480x16 or 640x480x256. The same resolution looks sharper on a small screen than a larger one.
Rich Media. Information that consists of any combination of graphics, audio, video, and animation, which is more storage and bandwidth intensive than ordinary text.
Rich Text Format (RTF). A standard for specifying the formatting of documents. Some documents formatting languages using RTF include Hypertext Markup Language.
Security functions. Securing areas of your Web site can allow visitors to your site to submit credit card payments online or access sensitive information (e.g. account information).
Search Engines. Software that searches for data based on some criteria. Although search engines have been around for decades, they have been brought to the forefront since the World Wide Web exploded onto the scene.
Server-side. Occurring on the server side of a client-server system. For example, on the World Wide Web, CGI scripts are server-side applications because they run on the Web server. In contrast, JavaScript scripts are client-side because they are executed by your browser (the client). Java applets can be either server-side or client-side depending on which computer (the server or the client) executes them.
Shopping cart. Shopping carts serve two functions: to manage your Web-based inventory and to help you design a browser interface for displaying your product or service line.
Streaming Video. Video transmission over a data network. The term implies a one-way transmission to the viewer, in which both the client and server software cooperate for uninterrupted motion. The client side buffers a few seconds of video data before it starts sending it to the screen, which compensates for momentary delays in packet delivery. Videoconferencing, on the other hand, requires real-time two-way transmission for effective results.
Thumbnail. A miniature display of a page to be printed. Thumbnails enable you to see the layout of many pages on the screen at once. Generally, thumbnails are too small to show the actual text, so greeking is used to indicate how the text will look.
URL. Uniform Resource Locator (formerly Universal Resource Locator). An Internet address which tells a browser where to find an Internet resource. For example, the URL for Boyd Design Studio is http://www.BoydDesignStudio.com/.
Web Browser. The program that serves as your front end to the World Wide Web on the Internet. In order to view a site, you type its address (URL) into the browser's Location field; for example, www.computerlanguage.com, and the home page of that site is downloaded to you. The home page is an index to other pages on that site that you can jump to by clicking a "click here" message or an icon. Links on that site may take you to other related sites.
Web Page. A single document in a World Wide website written using the HTML language. XML. (EXtensible Markup Language) An open standard for describing data from the W3C. It uses a similar tag structure as HTML; however, whereas HTML defines how elements are displayed, XML defines what those elements contain. HTML uses predefined tags, but XML allows tags to be defined by the developer of the page. Thus, virtually any data items, such as product, sales rep, and amount due, can be identified, allowing Web pages to function like database records. It is expected to become the dominant format for electronic data interchange.
Web Server. A Web server is a computer that is permanently connected to the Web and runs special software that allows it to provide information to Web users. There are hundreds of thousands of such servers connected to the Web. Only by creating your own Web server with your files on it, or by placing your files on someone else's server, can your site really become part of the Web.
World Wide Web. A system of Internet servers that support specially formatted documents. The documents are formatted in a markup language called HTML (Hypertext Markup Language) that supports links to other documents, as well as graphics, audio, and video files. This means you can jump from one document to another simply by clicking on hot spots. Not all Internet servers are part of the World Wide Web. There are several applications called Web browsers that make it easy to access the World Wide Web; Two of the most popular being Netscape Navigator and Microsoft's Internet Explorer. World Wide Web is not synonymous with the Internet.
WYSIWYG. Pronounced "wiz-zee-wig". An acronym for "what you see is what you get'. A WYSIWYG application is one that enables you to see on the display screen exactly what will appear when the document is printed. This differs, for example, from word processors that are incapable of displaying different fonts and graphics on the display screen even though the formatting codes have been inserted into the file. WYSIWYG is especially popular for desktop publishing and Web design.