The Spiral model is pretty much similar to the incremental model in which more emphasis is placed on risk analysis during the course. In the emerging IT industry, risk factor is part and parcel of the process. Instead of avoiding the risk elements, it is advisable to identify the risk and apparently to build the alternative solution. It is referred as risk analysis. The four phases adopted in the Spiral model are explained in the following diagram:

Identification: In the first phase, that is, the Identification phase, it is essential to find out the purpose of the software along with the measures to be taken. It helps to achieve a software to serve all your requirements.

The key coverages in the first phase are listed as follows:

• Studying and gathering requirements
• Detailed study on the feasibility
• Reviews run by a walkthrough to streamline the requirements
• Understanding the requirements document
• Finalizing the list of requirements
• Reviewing the project to take the decision to continue with the next spiral
• If the decision to continue is taken, plans are drafted for the next phase

The core purpose is to identify the business requirements of the system.

Design: This phase calculates all the possible risks with the possibility to encounter; apparently, it is the process to figure out how you would resolve these risks.

The key coverages in the second phase are listed as follows:

• The potential risks are identified based on the drafted requirements and brain-storming sessions
• On identification of the risks, the mitigation strategy is designed and finalized to roll out
• As an artifact, a document is generated to highlight all the risks and its mitigation plans

The core agenda of this phase is to identify the associated risks.

Build: In this phase, the target software is constructed and tested for its core functionality, reliability, and security aspects.

As the core engineering phase, the key coverages in this phase are listed as follows:

• The actual development and testing of the planned software
• Coding of the product
• Execution of the test cases and test results
• Generation of the test summary report and defect report

It focuses on the process of development and testing the target software.

Evaluation: After the current cycle has completed to produce the first prototype, the cycle is re-planned and repeated. The process proceeds to get into the next prototype 2.

As the final step of evaluation, these two key steps are executed:

• Customer evaluates the produced software to provide their feedback for the approval
• Generating the release document to highlight the implemented features

The main purpose of this phase is to plan for the next iteration, if required.

In software development, the aforementioned four phases are repeatedly passed in multiples of iterations named Spirals. In the baseline spiral, the process starts with the planning phase, requirements are gathered, and risk is assessed. Each subsequent spiral builds on the baseline spiral.