Usability and software architecture

The role of software architecture with respect to usability has evolved over the past 20 years. The architectures of the 1980s and early 1990s assumed that usability was primarily a property of the presentation of information. Therefore, simply separating the presentation from the dialogue and application made it easy to modify that presentation after user testing. A more popular belief in the 1990s was that usability concerns greatly affected system functionality as well as the presentation. This emphasis took attention away from architectural support (beyond separation). Achieving the correct functionality for a given system became paramount. It is our observation that even if presentation and functionality of a system are well designed, the usability of a system can be greatly compromised if the underlying architecture does not support human concerns beyond modifiability. This paper will present a new role for software architecture in usability, preliminary research and practice stemming from this role and a research agenda for the future.