Overview

Software architecture for business systems is like the girding of a large building. It satisfies characteristics needed by the occupant, shapes the overall structure, and defines the boundaries of individual rooms. Unlike buildings, however, large scale business systems have contradictory characteristics which can only be met with different structures. It’s as if we’re constructing a city, not just a single building. This paper defines some primary architecture characteristics of business systems, and, based on user requirements to meet these characteristics, proposes four engineering models for architectural patterns which together define an overall software architecture. First, this paper describes seven primary characteristics of business systems. Different business functions within a system have contradictory user requirements for each of these characteristics. The contradiction and tension in these user requirements become forces for the individual engineering model architecture patterns. Then, this paper presents four engineering model patterns which together meet the main requirements of these characteristics. The engineering models are: Online, Messaging, Batch and Stream IO. Online provides quick response to user interaction, using unpredictable access paths across all the complexity of the business model. Messaging, although possibly initiated by user interaction, provides complex processing with delayed responses using more predictable access paths. Batch is scheduled, has no user interaction, and provides processes which ar