Information system architecture
What is System Architecture and Why Do We Care?
If we were setting out to build a home, we would first lay out the floor plans, grouping each room by function and placing structural items within each room according to their best utility. This is not an arbitrary process – it is architecture. Moving from home design to IT system design does not change the process. Grouping data and processes into information systems creates the rooms of the system architecture. Arranging the data and processes for the best utility is the result of deploying an architecture. Many of the attributes of building architecture are applicable to system architecture. Form, function, best use of resources and materials, human interaction, reuse of design, longevity of the design decisions, robustness of the resulting entities are all attributes of well designed buildings and well designed computer systems. 
In general, architecture is a set of rules that defines a unified and coherent structure consisting of constituent parts and connections that establish how those parts fit and work together. Architecture may be conceptualized from a specific perspective focusing on an aspect or view of its subject. These architectural perspectives themselves can become components in a higher–level architecture serving to integrate and unify them into a higher–level structure.
The architecture must define the rules, guidelines, or constraints for creating conformant implementations of the system. While this architecture does not specify the details on any implementation, it does establish guidelines that must be observed in making implementation choices. These conditions are particularly important for component architectures that embody extensibility features to allow additional capabilities to be added to previously specified parts.  This is the case where Data Management is the initial deployment activity followed by more complex system components.
By adopting a system architecture motivation as the basis for the IT Strategy, several benefits result:
Business processes are streamlined – a fundamental benefit to building enterprise information architecture is the discovery and elimination of redundancy in the business processes themselves. In effect, it can drive the reengineering the business processes it is designed to support. This occurs during the construction of the information architecture. By revealing the different organizational views of the
same processes and data, any redundancies can be documented and dealt with. The fundamental approach to building the information architecture is to focus on data. process and their interaction.
Systems information complexity is reduced – the architectural framework reduces information system complexity by identifying and eliminating redundancy in data and software. The resulting enterprise information architecture will have significantly fewer applications and databases as well as a resulting reduction in intersystem links. This simplification also leads to significantly reduced costs. Some of those recovered costs can and should be reinvested into further information system improvements. This reinvestment activity becomes the raison d’йtat for the enterprise–wide system deployment.
Enterprise–wide integration is enabled through data sharing and consolidation – the information architecture identifies the points to deploy standards for shared data. For example, most Kimball business units hold a wealth of data about products, customers, and manufacturing processes. However, this information is locked within the confines of the business unit specific applications. The information architecture forces compatibility for shared enterprise data. This compatible information can be stripped out of operational systems, merged to provide an enterprise view, and stored in data repositories. In addition, data standards streamline the operational architecture by eliminating the need to translate or move data between systems. A well–designed architecture not only streamlines the internal information value chain, but it can provide the infrastructure necessary to link information value chains between business units or allow effortless substitution of information value chains.
Rapid evolution to new technologies is enabled – client / server and object–oriented technology revolves around the understanding of data and the processes that create and access this data. Since the enterprise information architecture is structured around data and process and not redundant organizational views of the same thing, the application of client / server and object–oriented technologies is much cleaner. Attempting to move to these new technologies without an enterprise information architecture will result in the eventual rework of the newly deployed system.
 A Timeless way of Building. C. Alexander, Oxford University Press, 1979.
 “How Architecture Wins Technology Wars,” C. Morris and C. Ferguson, Harvard Business Review. March–April 1993, pp. 86–96.