Specification and Measurement Derived from System Operations Non Functional Requirements

Abran, A., Al-Sarayreh, K.T.

An operation is typically described initially as a non functional requirement at the system level. Systems engineers must subsequently apportion these system re-quirements very carefully as either software or hardware requirements to conform to the operations requirements of the system. A number of concepts are provided in the ECSS and IEEE standards to describe the various types of candidate operations requirements at the system, software, and hardware levels. This paper organizes these concepts into a generic standards-based reference model of the requirements at the software level for system operations. The structure of this reference model is based on the generic model of software requirements proposed in the COSMIC – ISO 19761 model, thereby allowing the measurement of the func-tional size of such operations requirements implemented through software.