Computers as Components, 3rd Edition

7.3 Requirements Analysis

Before designing a system, we need to know what we are designing. The terms “requirements” and “specifications” are used in a variety of ways—some people use them as synonyms, while others use them as distinct phases. We use them to mean related but distinct steps in the design process. Requirements are informal descriptions of what the customer wants, while specifications are more detailed, precise, and consistent descriptions of the system that can be used to create the architecture. Both requirements and specifications are, however, directed to the outward behavior of the system, not its internal structure.

The overall goal of creating a requirements document is effective communication between the customers and the ...