EIS InfoBook Multi-[name] description, undated

NYC 9/11 Public Portal Document

output is desirable for viewing by a large number of people, then it can be stored directly in the data server. It thus becomes available to any browser to look at through the application server. The level of effort and return on investment often is unwarranted to convert the sensor processing program and the analytical model to a three-tier architecture when, and this is the most important point, a very small number of people actually make use of this highly technical application.

Three-tier client/server is most effective in “disconnected" applications. This means that the client user spends a significant amount of time working with or looking at the data received rather than constantly interacting with a succession of newly received data. The requirement to have “real-time" visibility, access, and update for all the data in one’s operation at all times really reduces the value of investing in three-tier client/server. The rule to recall is that networks are always slower than computers. Adding communication layers (which one does in three-tier client/server) rarely improves "speed."

Internet/lntranet Multi-Architecture

The composite of all of the different architectures that EIS International supports is shown on Figure 5. In this multi-architecture system, individual computers using low bandwidth communications share information through communication servers with local area networks that have LAN databases and/or traditional two-tier client/server databases. The users may employ, for analytical purposes, a data warehouse. Across the top of the illustration are sites with very “thin" clients using only a browser to access an application server which then proceeds to access z3—^ any of the other servers. At the far top right is the combined browser and application site (our 0-0 combined three-tier and two-tier client/server site) which will ,.P. .P. provide the robust as well as data- sensitive maximization of

Figure 5 computing power and network capabilities.

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