Computer Education

World Wide Web
A WEB OF COMPUTERS
HOW THE WEB WORKS
WHO USES THE WEB
HISTORY
FUTURE TRENDS

PROGRAMMING LANGUAGES
Machine Language
Assembly Language
High-Level Languages
FLOW-MATIC
FORTRAN
BASIC

HOW COMPUTERS WORK
Operating System
Computer Memory
Bus
Input Devices
Central Processing Unit
Output Devices

HOW A CPU WORKS
INTRODUCTION
Function
Branching Instructions
Clock Pulses
Fixed-Point and Floating-Point Numbers

HISTORY
Early Computers
Transistor
The Integrated Circuit

FUTURE TRENDS


The amount of information on the Web continues to grow rapidly, as does the number of users around the world and the amount of online commerce. For many businesses, the Web is replacing traditional catalog ordering. In addition, people continue to extend and improve Web technology. Several research efforts are underway to generate new methods that search the Web for information, new methods for restricting access to intellectual property, and new technologies that will permit live Webcasts similar to television broadcasts.

Although most Web pages still use the HTML language, extensions and alternative technologies have been proposed. The Extensible Markup Language (XML) is becoming popular for business-to-business communication. Unlike HTML, in which the meaning of all tags is pre-determined, XML allows companies that use it to define their own tags. For example, a publisher and a bookstore might choose to define their own tags for information about authors, titles, and publication dates for the information they exchange. Similarly, an automaker and a dealership might choose to define their own unique tags for models, body styles, and price. XML definitions are only meaningful to the parties involved. For example, the automaker's software will not understand a book publisherís author tag, and the bookstore's software will not understand the automakerís body style tag.

Other alternative forms are also emerging. The Wireless Markup Language (WML) is designed to be used with small wireless devices such as Web-enabled cell phones. Several scripting languages are available, including ECMA Script (which was originally called JavaScript) and Visual Basic. Scripting is gaining importance as more sites use animation.

Another Web technology expected to gain importance is known as a Content Distribution Network (CDN) or mirroring. A CDN consists of multiple sites around the world that all contain the same information. When a user requests a page, the CDN directs the request to the closest copy. From a user's viewpoint, a CDN results in a faster response. From a company's viewpoint, a CDN is necessary because no single Web site can handle simultaneous requests from several hundred million users. The largest Web sites already use CDN technology.

Higher-speed Internet transmission facilities, known as broadband, are also helping improve response times. Broadband technologies include Asymmetrical Digital Subscriber Line (ADSL), which works over telephone wiring, and cable modems, which work over cable TV wiring. Each technology allows data to flow from an Internet service provider to a user's computer hundreds of times faster than traditional dialup modems.

auuuu.com©