Software Engineering

170
CHAPTER 9 
Software Requirements Management
time, throughput, and resource utilization levels that meet specified performance 
objectives. Software performance is dependent on the characteristics of the comput-
ing environment. Computing environment characteristics that must be considered 
during software architecture definition include, but are not limited to, the following:
1. 
Execution time
2. 
Memory utilization
a.
  Primary memory (random-access memory, RAM) consumption
b.
  Virtual memory (secondary storage) consumption
3. 
Swap time (virtual memory management read and write latency)
4. 
Data storage latency (the time it takes to access a particular location in storage)
5. 
Data storage throughput (the rate at which information can be read from or writ-
ten to the storage)
6. 
Interrupt latency (the time between the generation of an interrupt by a device 
and the servicing of the device)
9.3.3 
Structural unit synthesis
Design synthesis is the software engineering practice that establishes the structural 
units of the design solution or physical architecture. Structural units represent the 
building blocks of the software product and are specified to facilitate software imple-
mentation (coding and testing). Structural units are derived by combining similar 
functional units and resolving differences among the functional specifications. This 
results in an integrated specification for each structural unit. During software imple-
mentation, the majority of the coding is accomplished at the unit level of development.
9.3.4 
Structural component synthesis
Structural components are determined by identifying structural units that need to 
be integrated to provide intermediary structural assemblies. Structural components 
represent the incremental assembly, integration, and testing of the software prod-
uct providing successive levels of functionality. Structural components establish the 
strategy for software component integration and testing to be accomplished during 
software implementation.
Structural components are specified by identifying the functional and perfor-
mance characteristics that arise as a result of the integration of lower-level struc-
tural components or units. During software implementation, structural components 
may require additional code to be generated to administer execution control logic. 
This will result in the recognition of internal and external interfaces that must be 
exercised during component integration and testing.
9.4 
Requirement traceability
Software product requirements must be traceable throughout the functional and 
physical architectures to facilitate stakeholder change proposals, design change 

---

171
9.4 
Requirement traceability
requests, and product configuration audits. These architectural perspectives (func-
tional and physical architectures) establish the software 
product
 design (referred 
to as the 
architectural design
), which is distinctly different from the structural unit 
programmatic design devised during software implementation. During software 
implementation, each structural unit specification is transformed into an explicit 
design utilizing computing language–specific constructs. This programmatic design 
is utilized to implement software units in computing language instructions that are