SDLC Incremental Model: Usage, Advantages, and Disadvantages

What is Incremental Model?

The Incremental Model is a software development process in which requirements are broken down into multiple standalone modules of the software development cycle.  Incremental development is done in steps from analysis design, implementation, testing/verification, maintenance.

Each iteration passes through the requirements, design, coding and testing phases. And each subsequent release of the system adds function to the previous release until all designed functionality has been implemented.

The system is put into production when the first increment is delivered. The first increment is often a core product where the basic requirements are addressed, and supplementary features are added in the next increments. Once the core product is analyzed by the client, there is plan development for the next increment.

Characteristics of an Incremental module includes

•System development is broken down into many mini development projects

•Partial systems are successively built to produce a final total system

•Highest priority requirement is tackled first

•Once the requirement is developed, requirement for that increment are frozen

Incremental Phases

Requirement Analysis

Requirement and specification of the software are collected.

Design

Some high-end function are designed during this stage.

Code

Coding of software is done during this stage.

Test

Once the system is deployed, it goes through the testing phase.

When to use Incremental models?

•Requirements of the system are clearly understood

•When demand for an early release of a product arises

•When software engineering team are not very well skilled or trained

•When high-risk features and goals are involved

•Such methodology is more in use for web application and product based companies

Advantages and Disadvantages of Incremental Model

Advantages

•The software will be generated quickly during the software life cycle

•It is flexible and less expensive to change requirements and scope

•Throughout the development stages changes can be done

•This model is less costly compared to others

•A customer can respond to each building

•Errors are easy to be identified

Disadvantages

•It requires a good planning designing

•Problems might cause due to system architecture as such not all requirements collected up front for the entire software lifecycle

•Each iteration phase is rigid and does not overlap each other

•Rectifying a problem in one unit requires correction in all the units and consumes a lot of time

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