QUALITY ATTRIBUTES IN SOFTWARE ARCHITECTURE DESIGN

Quality attributes of large software systems are to a large extent determined the system’s software architecture, i.e. qualities such as performance and modifiability depend at least as much on the overall architecture as on the code level implementation. Our experience shows that there are conflicts between modifiability and performance. The largest conflicts occur when there is a requirement that it should be possible to modify the system by run-time reconfigurations. Consequently, there is a need for providing tradeoffs between modifiability and performance when designing the system’s architecture. Based on experiences from five industrial projects we define eight design guidelines and a small taxonomy for some performance related quality attributes as well as for attributes related to the modifiability of the system. We also incorporate the guidelines in a design method, thus making it clear how and when the guidelines should be used.