Introduction

Today businesses are faced with the challenge of a global economy. Users expect applications to be reliable and have a consistent interface regardless of what platform a client is running on. This demand for cross-platform applications and platform independence has arisen from the universality of HTML and the expansion of the Internet. The Internet has proven to be the great equalizer with its concept of universally accessible data.

Applications are not the same as HTML pages. They are written to work on specific operating systems to provide specific functions. When a business wants to share out those applications the same way that an HTML page is shared universally, there arrives the dilemma they can t do it. Unless they use Windows 2000 Terminal Services with Citrix MetaFrame.

Welcome to independent computing!

Understanding Mid-Tier Architecture

Citrix developed the concept of a mid-tier architecture for application sharing. Mid-tier architecture combines the strengths of the mainframe computing architecture and the distributed computing architecture.

The mainframe was the first type of computer. As you can see in Figure 14.1, the mainframe model supports remote terminals. Traditionally called dumb terminals because they contained no independent processing capabilities, mainframe terminals today are actually considered smart because of their built-in screen display instruction sets. Terminals rely on the central mainframe for all processing requirements and are used only for input/output. The terminals are simply a screen and a keyboard. As the user enters information through keystrokes, that data is sent to the mainframe which processes the data and...