Page #6 (Introduction -)

	Introduction -
	Visual Basic Developers Guide to ASP and IIS
	A. Russell Jones

Copyright 1999 SYBEX Inc.

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	What Should You Expect to Get Out of It?

	In the same way that building client-server applications required a different model than building applications for stand-alone computers, building applications for the Web requires yet another model. In some ways, we've gone full circle from the mainframe days, when a "smart" mainframe computer supplied data and formatting to dumb terminals. As the terminals became PCs and got smarter, program designers decentralized the model. They moved processing away from the central computer and onto the client, but the data (which companies needed to share among many people) remained centralized.

	Unfortunately, the decentralized, fat-client model had its own set of problems. Clients aren't all the same, so programs often had to be rewritten multiple times so they would run on different client hardware configurations. When Windows became the dominant client platform, it eased this situation a bit by providing a common way for clients to talk to networks and peripherals. However, enough differences remained to make the client-server program a difficult model to maintain.

	The Web repopularized the idea of a smart central processing unit—the Web server, connected to remote terminals. The remote terminals, though, are now PCs that—unlike the old dumb terminals—are powerful enough to be efficient at processing graphical displays. The central processing unit no longer needs to be an expensive mainframe; instead, it can be a relatively inexpensive PC server, or better still, a collection of servers linked together to provide information upon request.

	In essence, the key to a successful Web application lies in storing information on the server in such a way that retrieving that information and getting it to the client is a smooth and fast operation. If it is not, the server will eventually bog down with unfulfilled requests, the clients will be left waiting, and your application will be unsuccessful. In this book, I'll provide a model that will enable you to build applications that scale from workgroup to enterprise without significant changes in the applications' structure. I'll also help you take advantage of another change in the programming paradigm—one that is not new, but that takes on additional importance in the interconnected world of Web programming—component-based programming.