5
Prototype model
In a prototype model, the developers create a prototype of
the application based on a limited version of the user require-
ments (Fig. 4). It is basically a hollow shell showing some of
the basic features and functionality of the system. A critical
drawback of this model is that, from the users' perspective,
the prototype may be seen as the final product and some of
the original requirements may now seem not to be needed.
However, after using the prototype for a while, some of the
requirements that were not considered necessary may become
desirable or the user may have new requirements that were
not initially considered. Because of this problem, the prototype
may sometimes have to be redesigned to add new functional-
ity; this, in turn, increases the development cost.
Software Engineering (continued)
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Fig. 3: Waterfall model.
Fig. 4: Prototype model.
Waterfall model
The Waterfall model is shown in Fig. 3. In this
model, the requirements are finalized early in the
cycle, allowing for fewer miscommunications and
the completion of the project in a timely man-
ner. On the other hand, this characteristic can also
be seen as a disadvantage because it is difficult
to introduce new requirements at later phases of
the development process. The model does not by
nature lend itself well to progressive enhancement
and incremental planning.
