Definitions

Functional Requirements

The fundamental subject matter of the system. Measured by concrete means like data values, decision making logic and algorithms.

Non-Functional Requirements

The behavioural properties that the specified functions must have, such as performance, usability, etc. Non-functional requirements can be assigned a specific measurement.

Project Constraints

Identify how the eventual product must fit into the world. For example, the product might have to interface with, or use some existing hardware, software or business practice, or it might have to fit within a defined budget or be ready by a defined date.

Project Drivers

The business-related forces. For example, the purpose of the product is a project driver, as are all of the stakeholders - each for different reasons.

Project Issues

Define the conditions under which the project will be done.