Chapter 15 - High assurance software architecture and design

Abstract

When a software is constructed, it needs to be carefully architected and designed to get benefitted from the inherent features of software quality. In addition to hardware, which is usually taken as the primary source for improving performance, design and architecture has high impact on the performance of a software application. Software design impact various aspects of software quality including reusability, maintainability, flexibility, reliability, and efficiency. Software architecture ensures the presence of quality in a software application by implementing structures like design principles and patterns and by avoiding antipatterns while applying these constructs. Design principles outline the most common scientifically derived approach for constructing a flexible and robust design. Use of design principles provide established guidelines to construct quality solutions. Design patterns relies on proven object-oriented design approaches to construct reliable and reusable solutions for the associated design problems in a system. One of the key purposes of most of the design patterns is to create a simple solution which is extendible and loosely coupled. Hence the design produced as a result of applying design patterns, eventually reduce the inter dependencies between program components and makes them easier to extend and maintain. Antipatterns identify the improper application design which leads to increased development time and can become a bottleneck in the performance of the application. They provide a legitimate way to document the problem scenarios along with their solutions which assist the designers to watch out similar situations in order to avoid bugs and other design constraints that hinders performance. Studies indicate improvements in quality factors using design and architectural refinements. Accordingly, for the application that lacks these quality attributes, it can be redesigned or refactored to incorporate these features of software quality.