PROTOTYPING MODEL
Ø The goal of a prototyping –based development process is to counter
the limitation of WFM. Requirement frozen.
Ø Instead of freezing the requirements before any design or coding can proceed, a throwaway prototype
is built to help understand the requirements. This prototype is developed based
on the currently known requirements.
Ø By using this prototype, the client can get an actual feel of the
system, because the intraction with the prototype can enable the client to
better understand the requirements of the desired system. This results in more
stable requirements that change less frequently.
Ø After the prototype has been developed, the end user & clients
are given an opportunity to use the prototype & play with it.
Ø Based on their experience, they provide feedback to the developers
regarding the prototype: What is correct, what needs to be modified, what is
missing, what is not needed.
Ø Based on the feedback, the initial requirements are modified to
produce the final requirements specification, which is then used to develop the
production quality system.
ADVANTAGES
1)
It is well suited for projects
where requirements are hard to determine & the confidence in obtained
requirements is low.
2)
It is an excellent technique
for reducing some types of risks associated with a project.
3)
By using COST CUTTING METHODS,
it is possible to keep the cost of prototype less than a few percent of the
total development cost. COST CUTTING METHODS-Minimal documentation,
Reduce Testing.
DISADVANTAGES
1)
Inferior, temporary design
solutions may become permanent
after a while, when the developers has forgotten that they were only intended to be
temporary.(Result in poor software quality)
2)
Customer may object to
prototyping being thrown away & may
demand “ a few changes” to make it working .(Result in poor s/w quality &
maintainability)
3)
MINIMAL DOCUMENTATION may cause
problem, in prototyping. Design doc, a test plan, a test case specification r
not needed during the development of prototype. REDUCE TESTING
cost cutting measures-but results in low quality product.
èPrototyping is often not used , as
it is feared that development costs may become large. However, in some
situations, the cost of s/w development without prototyping may be more than
with prototyping. There r two major reason for that………..
a)
The experience of developing
the prototyping might reduce the cost of the the later phases when the actual
software development is done.
b)
In many projects the
requirements are constantly changing, particularly when development takes a
long time.
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