ITERATIVE ENHANCEMENT or EVOLUTIONARY MODEL
Ø This model counters the limitation of WFM that requirements be
completely specified before the rest of the development can proceed & tries
to combine the benefits of both prototyping & WFM.
Ø One effective use of this type of model is for product development.
Ø The s/w should be developed in increments, each increment adding
some functional capability to the system until the full system is implemented.
Ø At each step (iteration), extensions & design modification can
be made.
Ø Each iteration passes through the requirements, design,
implementation & testing process.
Ø A working version of s/w is produced during the first iteration, so
u have working s/w early on during the s/w development life cycle.
Ø Subsequent iterations build on the initial s/w produced during the
first iteration.
Ø First a version is released that contains some capability. Based on
feedback from users & experience with this version, a list of additional desirable’s
features & capabilities is generated. These features form the basis of
enhancement of the s/w & are included in the next version.
The first
version contains some core capabilities & then more are added to later
versions.
ADVANTAGES
1)
Generates working s/w quickly
& early during the s/w life cycle.
2)
More flexible –less costly to
change scope & requirements.
3)
Easier to test & debug in
each increments than testing entire system as in WFM.
4)
Easier to manage risk becoz
risky pieces r identified & handled during its iterations.
5)
Each iteration is an easily
managed milestone.
DISADVANTAGES
1)
In generating business
contract- how will the cost of additional features be determined &
negotiated, particularly becoz the client organization is likely to be tied to
the original vendor who developed the first version.
2)
Problems may arise pertaining
to system architecture becoz not all requirements are gathered up front for the
entire s/w life cycle.
3)
Each phase of an iteration is
rigid & do not overlap each other.
0 comments: