SYSTEM DEVELOPMENT LIFE CYCLE MODELS

SYSTEM DEVELOPMENT LIFE CYCLE MODELS.

WATERFALL MODEL. Waterfall-model. The waterfall model is a linear, sequential approach to the software development life cycle (SDLC) that is popular in software engineering and product development..

ADVANTAGES AND DISADVANTAGES OF WATERFALL MODEL.

ADVANTAGES. Before the next phase of development, each phase must be completed. Suited for smaller projects where requirements are well defined. They should perform quality assurance test (Verification and Validation) before completing each stage. Elaborate documentation is done at every phase of the software’s development cycle. Project is completely dependent on project team with minimum client intervention..

DISADVANTAGES. Error can be fixed only during the phase. It is not desirable for complex project where requirement changes frequently. Testing period comes quite late in the developmental process. Documentation occupies a lot of time of developers and testers. Clients valuable feedback cannot be included with ongoing development phase..

ITERATIVE MODEL. The iterative model is a software development approach that breaks down projects into smaller, manageable chunks called iterations..

ADVANTAGES AND DISADVANTAGES OF ITERATIVE MODEL.

ADVANTAGES. It is easily adaptable to the ever changing needs of the project as well as the client. It is more cost effective to change the scope or requirements in Iterative model. Testing and debugging during smaller iteration is easy. Risks are identified and resolved during iteration; and each iteration is an easily managed. One can get reliable user feedback, when presenting sketches and blueprints of the product to users for their feedback..

DISADVANTAGES. More management attention is required. It is not suitable for smaller projects. Highly skilled resources are required for skill analysis. Project progress is highly dependent upon the risk analysis phase. Defining increments may require definition of the complete system..

INCREMENTAL MODEL. Incremental Model is a process of software development where requirements are broken down into multiple standalone modules of software development cycle..

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. 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 It is costlier than waterfall model..

SPIRAL MODEL. Spiral Model is a risk-driven software development process model. It is a combination of waterfall model and iterative model..

ADVANTAGES AND DISADVANTAGES OF SPIRAL MODEL.

ADVANTAGES. Additional functionality or changes can be done at a later stage. Cost estimation becomes easy as the prototype building is done in small fragments. Continuous or repeated development helps in risk management. Development is fast and features are added in a systematic way in Spiral development. There is always a space for customer feedback..

DISADVANTAGES. Risk of not meeting the schedule or budget. Spiral development works best for large projects only also demands risk assessment expertise. For its smooth operation spiral model protocol needs to be followed strictly. Documentation is more as it has intermediate phases. Spiral software development is not advisable for smaller project, it might cost them a lot..

PROTOTYPE MODEL. Prototyping Model is a software development model in which prototype is built, tested, and reworked until an acceptable prototype is achieved. It also creates base to produce the final system or software..

ADVANTAGES AND DISADVANTAGES OF PROTOTYPE MODEL.

ADVANTAGES. Users are actively involved in development. Therefore, errors can be detected in the initial stage of the software development process. Missing functionality can be identified, which helps to reduce the risk of failure as Prototyping is also considered as a risk reduction activity. The prototype helps to gain a better understanding of the customer’s needs. Prototypes may offer early training for future users of the software system. No need for specialized experts to build the model..

DISADVANTAGES. Prototyping is a slow and time taking process. There may be far too many variations in software requirements when each time the prototype is evaluated by the customer. The cost of developing a prototype is a total waste as the prototype is ultimately thrown away. It is very difficult for software developers to accommodate all the changes demanded by the clients. The client may lose interest in the final product when he or she is not happy with the initial prototype..

AGILE MODEL. The Agile Model is an incremental and iterative process of software development. It defines each iteration’s number, duration, and scope in advance..

ADVANTAGES AND DISADVANTAGES OF AGILE MODEL.

ADVANTAGES. Changes are acceptable at any time. You can reduce the overall development time by utilizing this Agile Model. Updated versions of functioning software are released every week. The final product is developed and available for use within a few weeks. Communication with clients is on a one-on-one basis..

DISADVANTAGES. There is a higher risk of sustainability, maintainability, and extensibility. In some corporations, self-organization and intensive collaboration may not be compatible with their corporate culture. Documentation and design are not given much attention. Without clear information from the customer, the development team can be misled. Not a suitable method for handling complex dependencies..

RAD MODEL. RAD Model (Rapid Application Development model) is a software development process based on prototyping without any specific planning..

ADVANTAGES AND DISADVANTAGES OF RAD MODEL.

ADVANTAGES. [image] • It is adaptable and flexible to changes. • It is useful when you have to reduce the overall project risk. • It is easier to transfer deliverables as scripts, high-level abstractions and intermediate codes are used. • Each phase in RAD delivers highest priority functionality to client. • With less people, productivity can be increased in short.

DISADVANTAGES. It can’t be used for smaller projects. Not all application is compatible with RAD. When technical risk is high, it is not suitable. If developers are not committed to delivering software on time, RAD projects can fail. Requires highly skilled designers or developers..