Software Engineering

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CHAPTER 10 
Formulating the Functional Architecture
convoluted. This will require extensive user training and may dissuade potential 
customers from adopting the software product as an institutional standard. 
Design complexity directly translates into code intricacy and obscurity. 
Software sustainment costs will increase in proportion to the complexity of the 
design. The functional architecture provides the initial design paradigm where 
complexity can be regulated.
The objective of functional analysis and allocation is to formulate a complete, 
consistent, and verified functional architecture that conforms to the specified soft-
ware requirements. The software architecture must identify every data processing 
task, including failure detection, remediation actions, and consequential degraded 
modes of operation. The functional architecture is complete when every functional 
component, unit, and interface has been specified. Functional units and interfaces 
are the “building blocks” used to derive the physical architecture for the software 
product. The physical architecture identifies and specifies the structural software 
elements that will be elaborated (designed, coded, integrated, and tested) during 
software implementation. Chapter 12 describes the physical architecture and how it 
is derived from the functional architecture.