5 Types of Software Development Life Cycle Model

Software Development Life Cycle Model is also known as SDLC. It refers to the process of developing, coding, testing, debugging and deploying the software to the consumer. The operation of SDLC is maintained by the software developer under the supervision of the project team lead within the organisation.

The term Life Cycle indicates that the process is continuous; it is redesigned to improve the quality and expectations of the software. The life cycle model is followed to successfully deploy the software. It is set on par with the industry approach.  

Need for SDLC model

The ultimate goal of the SDLC is to create software which gives a better user interface to the consumer with the flexible features required by the end users and with a minimal budget. The life cycle goes through several iterations to re-design to satisfy the end user's expectation and need. 

The Model is chosen concerning the product and project. The model is structured to save time and give a clear idea of the phase to make it cost-effective.

General Phases

The SDLC model comprises various phases. The general phases of the SDLC model are requirement analysis, design, code, test and deployment. 

  1. Requirement analysis: It is the initial step for any development of software. The client/customer gives their requirement for the product to the developer team. The team collects all the necessary details for the development of the software. They analyse and document the collected details for future reference. 

  2. Designing and code: After the first phase, the team moves to the designing stage. Here, the team designs the interface of the software. Based on the requirement of the customer, the team writes code for the functioning of the product.

  3. Test: After the designing phase, where the team has to design a code for the product, it moves to the implementation part. Here the team checks for the error/malfunction of the product. If the product is error-free, it moves to the next phase or else, the team checks for the error and it's sent back to the designing team where they revise the collected data from the requirement analysis of the user, for a better understanding.

  4. Deployment: After completing all the phases, the product is now ready for supplying to the customer i.e, making it available in the market. In this phase, the customer buys, and gives feedback for the product - product efficiency, working and if there is any scope for improvement.

Types of the lifecycle model

The Life Cycle model is split into several types to meet up to the expectation and demands of the client.

1. Waterfall model:

It is a linear sequential process; flowing steadily downwards like a waterfall. 

How it works - The second phase begins only after the completion of the first phase. i.e, all the phases are independent of each other.

When to use - It is used only when the requirements are well-known, clear and fixed. This model is preferred for short projects and when the product definition is stable.

Phases -

Requirement Analysis➡ Design➡ Implement➡ Verification➡ Deployment➡ Maintenance

Advantages -

  • Easy to understand and structured approach.
  • Documentation is required for each phase                         

Disadvantages - 

  • Documentations are long, detailed and boring to read.

2. Spiral model:

It is an important model in SDLC. It has a sequence of activities.

How it works - Each activity is dependent on another activity.

When to use - A big budget project or when the requirement is complex and a long-term project. i.e, when the customer requirement is clear.

Phases -

System Feasibility ➡Requirement Definition➡System design➡  System testing 

Advantages -

  • Reduces the high amount of risk
  • More no documentation approval is not required

Disadvantages - 

  • Expensive
  • It is not suited for a small project

3. V model:

It is known as the verification and validation model. It is a sequential process.

How it works: After completing the first phase, the second phase starts. After each phase's completion, testing takes place.

When to use - It is preferred when the client's requirement is for a small medium-sized project. When the requirement is clear, fixed and defined previously.

Simple technical resources are used.

Phases

Advantages -

  • Easy to understand and apply
  • Works well for a smaller project
  • Saves time

Disadvantages - 

  • Requirement changes are not supported
  • Expensive

4. Incremental model: This model is iterative. 

How it works - It will be released phase by phase. It releases a partial part of the system and gradually the functionality is added based on the demands and needs of the customer.

When to use - Requirements are not fixed or it gets increased with time. Examples include Ola, Uber, and Amazon. Also when there is a need to get a product to market early.

Phases - 

Requirement

↙ ↓ ↘  (Iterations)

Design and Development

Testing

Implementation

Advantages -

  • Generates working of software quickly and early delivery.
  • More flexible
  • During smaller iterations, it is easier to test and rectify errors.

Disadvantages-

  • Expensive
  • Need a clear and complete definition before commencing it.

5. Agile process:

Testing and coding are done in an incremental and iterative approach. It includes the core values of adaptability.

How it works - Breaking the project into several iterations. The phase which has the highest priority will be developed first. It will continually update the requirement if the customer requires changes.

When to use - When there is no fixed requirement or demands requirement changes. To save money and time.

Phases - 

Requirement ➡ Design ➡Development ➡ testing➡  Deployment

Advantages -

  • Customer satisfaction and continuous delivery
  • Accepts changes in the requirement
  • Cost-effective

Disadvantages - 

  • designing and documentation are not properly maintained
  • Not ideal for a long-term project

Written By: Durrah Ismail Nasir

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