There are several closely related methods for doing structured analysis and design including Yourdon/DeMarco and Ward/Mellor. The Hatley Pirbhai approach adds architecture and state models to specifically target real-time, multi-tasking systems. Here are some popular books on structured analysis and design: MacA&D and WinA&D fully support structured analysis and design as briefly summarized here: Show data flow in the system using process models (DFDs) and text specifications Show control information with control flows in the process model Use state models to highlight events, sequential and combinations actions and modes Show calling structure between functions with structure models Show communication between threads of execution (Tasks or ISRs) using the task model Return to Design Methods