search menu icon-carat-right cmu-wordmark

Pointing the Way Toward a Software Architecture Discipline


In studies dating back to 1978, data showed that the cost of development and modification of the user interface contributed over 50 percent of the total cost of software ownership. Attempts to reduce the cost of developing defense systems clearly had to include reduction in the cost of developing and maintaining the user interface.

The high cost of developing and modifying the user interface led to user interface management systems (UIMSs), a class of system intended to reduce this cost. Serpent was a UIMS that approached the problem of reducing the total ownership cost of the user interface by separating the user interface and functional portions of a system, allowing for modifications to the user interface with minimal impact on the remainder of the system.

Through its work on Serpent, the SEI contributed to a greater understanding by a generation of user interface researchers about the impact of software engineering architectural decisions on the ease of modifying the user interface. This work introduced an important concept to the discipline of software architecture that emerged in the 1990s.

Featured in