RUP Use Cases, the use case authors can write detailed use cases highlighting the above
multiple iterative prototyping loops…Subsequent build/release cycles for the same
product with enhanced features and benefits can bypass the iterative prototyping loops,
for example.
4.0 Existing and Emerging Software Metrics
Whereas organizations large and small have traditionally used FPA œ Function Point
Analysis, FPA variants like COSMIC œ Common Software Measurement International
Consortium take —Functional Sizing“ to the next level. Functional Sizing as a measure of
software is akin to the metric system for measuring length.
Even though countries like US have stuck to the older FPS system, the metric system is
nothing but a variant of the older FPS system. Similarly, COSMIC is an evolution of
FPA. Both approaches are discussed in detail as a prelude to weaving relevant concepts
into a software measurement worksheet later in this handbook.
Further, COCOMO II as yet another estimation methodology is described briefly, since it
seems to be useful in iterative software development projects, once the first iteration is
complete.
4.1 FPA - Function Point Analysis
Function points measure the size of the information processing system in terms of its
requirements. Since requirements are subject to change, FPA is at best, an estimate.
Nevertheless, it is an important first step in the challenging attempt to size any
information system. Also, it is better than measuring software in terms of mere size:
lines of source code, lines of documentation, number of classes, number of database
tables, etc --- because these size measures can be taken up after the software has
been built, not before!
Defining the system boundary is the first step in any FPA exercise. This helps identify the
relevant parameters œ internal and external. The System Boundary is an abstract interface
which exists between the application or software component being analyzed / estimated
and the overall computer / system environment in which it exists. The software
application being analyzed processes the information within the System Boundary.
On the one hand, information moves into the software application / component from
users / actors and from other applications / software components across the System
Boundary. On the other, the application / software component will produce information
