Pilot: The actual production system is installed at a single or limited number
of users. Pilot basically means that the product is actually rolled out to limited
users for real work.
Gradual Implementation: In this implementation we ship the entire product
to the limited users or all users at the customer end. Here, the developers
get instant feedback from the recipients which allow them to make changes
before the product is available. But the downside is that developers and testers
maintain more than one version at one time.
Phased Implementation: In this implementation the product is rolled out
to all users in incrementally. That means each successive rollout has some
added functionality. So as new functionality comes in, new installations
occur and the customer tests them progressively. The benefit of this kind of
rollout is that customers can start using the functionality and provide valuable
feedback progressively. The only issue here is that with each rollout and added
functionality the integration becomes more complicated.
Parallel Implementation: In these types of rollouts the existing application
is run side by side with the new application. If there are any issues with the
new application we again move back to the old application. One of the biggest
problems with parallel implementation is we need extra hardware, software,
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