Software Engineering

Requirements
Analysis
1960s – 1970s
1980s
1990s
40%
20%
10%
30%
60%
80%
30%
20%
10%
Preliminary
Design
Detailed
Design
Coding and
Unit Testing
Integration
and Testing
System
Testing
FIGURE 8.4
The allocation of effort to software development phases.

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8.6 
Establish the requirements baseline
change. Each change proposal must be authorized by the project-level change con-
trol board. Change requests involve a change to the software architecture to facili-
tate software implementation, testing, or sustainment activities. Change requests 
must be authorized by the technical-level change control board once the software 
product architecture is baselined.
Each time the requirements are allowed to be modified the impact of the change 
on the operational process, functional and physical architectures, specifications, 
documentation, test plans and procedures, work breakdown structure, and other 
related items needs to assessed. This leads to application features that weren’t origi-
nally planned and increases risk to software application quality or development 
schedule.