Supportsoft Glossary

Top-Down Design for Breaking Systems into Components

With a top-down design approach, software engineers implement an entire software system from its most abstract concept down, breaking the entire system down into successively smaller and more detailed pieces. The top-down design process begins with the definition of the overall objectives and major functional capabilities for the entire system. The next step is to break these broad concepts into functional sub-components and to break functional sub-components into module and task levels.

Another important value of using top-down design is clarity of purpose for development teams. It forces developers to consider the entirety of the system's structure before they begin to build components. This is particularly true in the case of complex systems, where taking into account the interrelationships among components (e.g., dependencies, data flows, etc.) is more difficult than in simpler systems.

In addition, the use of a structured top-down design method simplifies project management for a development team. The logical structure provided by top-down design allows teams to assign tasks in a logical manner, to see how the various components fit together, and to be able to check on progress more easily. By supporting these aspects of project management, a structured top-down design approach makes it possible for a final system that is developed to continue to be a coherent system as the system grows and evolves.