Software Engineering

4.3.5 
Software product baselines
The 
requirements baseline
 identifies the required software functional, performance, 
and interface characteristics that must be present for the product development to be 

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FIGURE 4.5
Evolution of the PBS.

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67
4.3 
Complexity control mechanisms
completed. It addresses the verification fundamental to demonstrating the achieve-
ment of those specified requirements. The requirements baseline is comprised of 
the software and computing environment requirement and interface specifications 
that will be used by the software test staff to confirm the product’s completeness 
during acceptance testing. The traditional software requirements baseline has 
been referred to as the functional baseline by the configuration management dis-
cipline. However, this baseline only addresses the software product functionality 
and ignores the functionality provided by the elements of the computing environ-
ment. Because a software product cannot be executed without the properly config-
ured computing environment, the term 
requirements baseline
 has been introduced. 
In essence, the requirements baseline is comprised of the functional baselines of 
the software configuration items (if there are multiple software configuration items) 
and the computing environment.
The 
allocated baseline
 defines the configuration items making up a software 
product and identifies how software functional and performance requirements are 
allocated across lower-level configuration items.
1
 It includes all functional, perfor-
mance, and interface characteristics that are allocated from top-level software con-
figuration items to functional components and units that comprise the functional 
architecture.
The 
product baseline
 describes all of the necessary functional and physical 
characteristics of a software configuration item and the tests necessary to demon-
strate the compliance of the configuration items with its specified requirements. The 
product baseline includes “code-to” specifications for software structural units and 
components that comprise the physical architecture.