Introduction
Incremental build is a software development approach in which
requirements are segregated into multiple standalone
modules/builds to be taken up during the software development
life cycle (SDLC). The idea is to divide cycles into small
manageable modules, which have to successfully pass-through
requirements, design, coding, and tests.
Each release is an increment towards another iteration until
the whole functionality is complete and ready to be delivered
to the customer. The increments are planned according to the
requirements to be met, beginning with the basic ones and
gradually moving on to add features until the process reaches
the end of increments. Hence, the term ‘incremental build
model’, where builds are incremented after successful release
to the next cycle.
Let us now look at the various stages of the Incremental
Model.
Phases in Incremental Model
The phases of the incremental model are broadly categorized
into four levels, each of which has to pass through requisite
validations to move to the next phase.
-
Requirements Analysis: The requirements analysis phase is the one where the
product and system requirements are analyzed. This phase
lays the foundation upon which the subsequent phases rely.
This phase gathers the requirements and checks for their
feasibility to implement in the given environment, before
moving on to the next increment.
-
Design and Development: This phase deals with the design and development of system
functionalities. Once the increments proceed to further
levels, the model developed and designed in this phase is
referred to.
-
Testing: Each functionality is tested for performance as well as
additional functionalities. The purpose is to test the
behavior of each task. Implementation: This is the final
stage where code is written to implement the designed
functionality.
-
Implementation: This is the final stage where code is written to implement
the designed functionality.
To simply understand, to complete a product which is divided
into four modules, say Module 1, Module 2, Module 3, and
module 4, first Module 1 will go through all the phases of the
incremental model discussed above. Then the next module,
Module 2, will pass through the four phases, then Module 3,
and so on until all modules are ready to be integrated as one
suite of complete software. One module once completed, is
deployed to the production environment, after successful
testing.
Types of Incremental Models
The incremental models can be of the following types:
-
Stage Delivery model: In this model, the product being developed is incrementally
delivered to the customer. Each build is developed with a
purpose to solve and thus ensures that the functionalities
are delivered without waiting for the completion of the
entire software. The software is delivered in successive
stages throughout the project life cycle.
-
Parallel Development model: Such a development methodology refers to a process where
different changes have to be made on related code bases. For
instance, a developer team may be working on some feature
update on the released version/module of the product,
whereas a product maintenance team might be required to work
on a security patch update, and so on. So, in this case,
both the teams are working in parallel on the same code
base, which is merged later into a single release of the
product.
Advantages of Incremental Model
Some prominent advantages of the incremental model are listed
below:
-
An incremental approach makes it easy to understand the code,
and therefore errors are much easier to track.
-
Flexibility to change as per any change in the requirements.
- Less expensive than other models.
-
The customer has the flexibility to provide their feedback in
case there is a need for any change for any of the builds.
-
Due to a smaller number of modules in a single iteration, it
becomes easy to handle probable risks.
- Initial module deliveries are faster.
-
Due to smaller builds in every iteration, it is easier to
perform rigorous testing.
Disadvantages of Incremental Model
Now that we have listed the various advantages of the
incremental approach, let us move on to understanding some of
its disadvantages. These are:
-
The incremental model definitely requires robust planning in
place, as to how to go about each iteration.
-
Each iteration in itself is quite rigid and cannot overlap
with each other.
- The incremental model definitely incurs higher costs.
-
Throughout the various iterations, it could be possible that
we may encounter some unforeseen system hurdles which cannot
be predicted at the very onset of the model development.
Why Incremental Model?
By now we have gathered a very detailed insight into what is an
incremental model and how it can be perceived. Software
development models have revolutionized over the past few decades
as per the requirements of the prevailing market trends. Every
model’s inception can be attributed to the software development
requirements it met before it came into existence as a
full-fledged model. Hence, there could often be some questions
pertaining to why one should go for an incremental model. We
summarize a few takeaway points that should help the readers to
get a better understanding as to why and in what circumstances
one should go for an incremental build.
-
Whenever the set of requirements are concise in nature or we
can say very clearly understood, in such a case incremental
model can be the best resort.
-
The incremental model can be a solution when there is a need
to deliver a product earlier and faster.
-
When a newer technology is being put to use, the incremental
model can help the team go step by step, minimizing the
chances of producing erroneous results, as builds can be
analyzed in increments.
-
There could be situations when there is a dearth of skilled
resources, maybe due to less experience or lack of knowledge
and expertise in the desired technology. Such situations can
be handled well with an incremental build model by the
amalgamation of various resources at various stages.
-
In cases where there could be chances of features of
requirements that are difficult or risky in nature, going with
short and steady increments could be highly beneficial.
Conclusion:
Among a plethora of software development models, it is
strongly recommended to perform a careful analysis of the
product in question. The models have evolved to solve a
purpose and therefore it is very necessary to develop a clear
understanding of its applications for a fruitful
implementation.
