Page 144 - DCAP305_PRINCIPLES_OF_SOFTWARE_ENGINEERING

Principles of Software Engineering

Notes A structure chart is also used to diagram associated elements that comprise a run stream or thread.
It is often developed as hierarchical, but other representations are allowable. The representation
must describe the breakdown of the configuration system into subsystems and the lowest
manageable level. An accurate and complete structure chart is the key to the determination of
the configuration items, and a visual representation of the configuration system and the internal
interfaces among its CIs. During the configuration control process, the structure chart is used to
identify CIs and their associated artifacts that a proposed change may impact.

Structure chart construction
A structure chart can be developed starting with the creating of a structure, which places the
root of an upside-down tree which forms the structure chart. The next step is to conceptualize
the main sub-tasks that must be performed by the program to solve the problem. Next, the
programmer focuses on each sub-task individually, and conceptualizes how each can be broken
down into even smaller tasks. Eventually, the program is broken down to a point where the
leaves of the tree represent simple methods that can be coded with just a few program statements.
In practice, first it is checked if a Structure Chart has been developed already. If so an expert
needs to review it to ensure it represents the current structure and if not, updates the chart
where needed. (See Figure 6.9)

Figure 6.9: Structure Chart Construction

SME
CM Rep Review &
Is Structure Yes Update
START Chart Structure END
Available?
Chart
No
SME SME SME SME
Create Analyze Subdivide CS Document
Structure Configuration into SS, LSS Subdivisions
Chart System & Cls as Blocks

SME SME SME CM Rep
Analyze the Select Compare SME Is item Yes Designate
Structure a Item to CI a CI? as a CI
Chart Block Attributes
No

CM CM
Rep Yes CM Rep SME CM Rep CM Rep Rep
More Remove No Is item Yes Designate Remove Document
No Blocks Block Part of as a Box in CS CM
? from SC a CI? Component Outline Worksheet
END

6.10 Data Flow Diagrams

Data flow diagrams (also called data flow graphs) are usually used during problem analysis.
Data flow diagrams (DFDs) are quite general and are not incomplete to problem analysis for
software requirements specification. They were in use long before the software engineering

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