Software Engineering

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12.2 
Structural design considerations
simulations, or engineering problem-solving techniques. Software prototyping has 
evolved into a scandalous practice that subverts formal software engineering prac-
tices in favor of incremental product development strategies. Current software pro-
totyping strategies involve four primary forms of prototyping
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 :
1. 
Rapid prototyping
—creating a working model of various parts of the software 
product at a very early stage, after a relatively short investigation. The approach 
used in constructing the prototype is usually quite informal, the most important 
factor being the speed with which the prototype is completed. The model then 
becomes the starting point from which users can reexamine their expectations 
and clarify their requirements. When this has been achieved, the prototype 
model is thrown away, and the system is formally developed based on the 
refined requirements.
2. 
Evolutionary prototyping
—creating a very robust prototype in a structured man-
ner and constantly refine it. The evolutionary prototype forms the foundation of 
the software product. This permits the software team to modify and extend the 
prototype in a manner that could not be conceived during the requirements and 
design activities. Evolutionary prototypes may be deployed and evolved through 
use in its intended operational environment. The software product is never “fin-
ished” and is “matured” as the operational environment changes.
3. 
Incremental prototyping
—the final product is built as separate prototypes that 
are integrated into an overall product configuration.
4. 
Extreme prototyping
—Extreme prototyping is used for developing web appli-
cations. It establishes a series of three incremental software builds. The first 
phase is a static prototype that consists of HTML pages to portray the page 
layout design. In the second phase, the HTML pages are dynamic to permit 
website navigation. In the third phase, the transaction processing functionality is 
implemented.
The misconception surrounding these software prototyping strategies is the sug-
gestion that this resembles engineering. While software prototypes serve a useful 
purpose in conventional software development approaches, the software industry has 
embraced an amateurish, evolutionary prototyping approach to software product design 
and development. This prolongs customer engagements as the product is evolved over 
time, results in failed or cancelled projects due to cost overruns and extensive schedule 
delays, and provides job security for many unqualified, undisciplined software special-
ists. Using, or perhaps misusing, prototyping has its disadvantages:
●
 
Faulty assumptions.
 The focus on a limited prototype can distract software ana-
lysts from addressing the complete scope of the problem space. This can lead 
to overlooking alternative design solutions, preparation of incomplete specifica-
tions, and a general lack of appreciation by the analysts for the complexity of 
the software problem space.
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See 
http://en.wikipedia.org/wiki/Software_prototyping#Types_of_prototyping

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