ABSTRACT
This chapter explores a more "creative" task domain, in which the user is not given specific instructions to follow, but must use the system to solve a problem. It explores human-computer interaction on a task that is not an instruction-following task: the computer-aided design of a VLSI circuit-layout. The design of a VLSI circuit is a complex problem, whose solution depends on finding an appropriate decomposition of a large circuit into sub-circuits. The experimental session is clearly partitioned into phases lasting several minutes each. In each phase, unit tasks are organized around one of the major subproblems of the VLSI circuit-layout problem. The case study of computer-aided circuit design suggests that the goals, operators, methods, and selection rules for the methods (GOMS) theory can be extended to semi-creative, human-computer interaction tasks that are not explicitly given, but are generated by the user.
