Software Engineering

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CHAPTER 10 
Formulating the Functional Architecture
10.1 
Motivation for the functional architecture
The functional architecture provides a working view of the software product with 
no physical or structural features. It is derived from the operational or business 
model from which the software requirements were specified. At the uppermost 
layer it identifies the principal software functions that interact with external entities 
to describe the software response to external stimuli. The principal functions are 
decomposed to provide additional details concerning the data processing services 
that the software product must provide. 
Figure 10.1
 addresses the role of the func-
tional architecture as the initial step in the translation of software requirements into 
a design for the software product.
The functional architecture expresses the purpose or use of the software product 
for which it is to be structurally designed. While the operational model describes 
the role of the software product in executing a business or operational process, the 
functional architecture explains the data processing actions the software product 
must perform. The functional architecture must ultimately be decomposed into ele-
mentary functions that yield a single result when invoked. Elementary functions are 
labeled functional units and must be specified to support the structural design of the 
software product.
FIGURE 10.1
Role of the functional architecture.

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