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.
