Chapter 7. Systems Engineering of Software-Intensive Systems

Key Points

• Systems engineering is a problem analysis technique especially suitable for embedded-systems development.

• Systems engineering helps us understand the requirements imposed on software applications that run within the solution system.

• Requirements flowdown is primarily a matter of ensuring that all system requirements are filled by a subsystem or a set of subsystems collaborating.

• Today, the system design must often be optimized for software costs rather than for hardware costs.

In Chapter 6, we looked at business modeling, a problem analysis technique for IS/IT applications. Business modeling helps us determine what application we should build and where we should run that application, within the context of the computing environment of the company and the departments, buildings , and political and physical constructs of the company itself. In other words, this analysis can help us determine why and where an application should come into existence. In so doing, of course, we make a subtle shift from the problem space to an initial look at the solution space , wherein the functionality that resolves the problem will exist on one or more applications that meet the user 's ultimate need.

In the embedded-systems business, however, the problem domain and the solution domain look entirely different. Instead of departments, people, and processes, the domains consist of connectors and power supplies , racks of equipment, electronic and electrical components , hydraulic and fluidic handling devices, other software systems, mechanical and optics subsystems, and the like. Here, business modeling cannot always provide value. Instead, we must look to a different strategy to help us determine the why and where questions. Here we find ourselves in the realm of the systems engineer .