Packaged applications come in all shapes and sizes. SAP, for example, provides modules for accounting, inventory, human resources, manufacturing and many other vital functions. PeopleSoft and Baan provide many of the same types of services and modules. Vendors, such as Lawson Software, JD Edwards and others, some with less than a dozen installations, offer packaged applications. Siebel, a sales-force automation package, is designed to allow sales organizations to function more effectively.
Centralized architecture is the most traditional and, as such, easiest to follow.
It places both data application logic and user interfaces within the same machine, generally a mainframe or large minicomputer that houses a packaged application accessible by dumb terminals. There are a number of advantages to centralized architecture. First, because the data, process logic and user interface all exist together on the same processor, maintenance is much easier than in traditional distributed environments. Second, integration is more easily accomplished within one machine than among several. In an EAI scenario, encapsulated services and data that reside on a central computer can be accessed by a single gateway.