There are various software development life cycle (SDLC) models that are used for the development of projects depending on its aims and goals. These models help you navigate through the complex process of software development. We will look into detail of only a select few.
Software Development Life Cycle Models
SDLC is a very important and basic notion of the software development process. SDLC are implemented to make a high quality software product or system. There are many types of these models. But you should choose the one that fits the needs of your project. The project’s timeframe, quality, budget and your expectations from it will make most of that decision for you though.
There are more than 50 recognized SDLC that are in use. They are not perfect. Each of them has their strengths and weaknesses. In this article we have selected only 8 for review.
This article has been put together by Hanna Schnaider, who is an expert in the field. A custom software outsourcing company that has expertise in delivering custom solutions, Fortyseven, will go in detail through what you require and only suggest the model that suit your project the best.
Group of SDLC
If you have been in the software development industry then you may know that there are four groups of SDLC and they are: evolutionary, sequential, formal and informal. These groups are made based on how the SDLC approach the workflow organization. It also depends on what kind of relationship is built between the customer and the development team. The sequential SDLC are easier to manage and implement. Waterfall and V-model are examples of sequential SDLC.
Evolutionary SDLC are rigid and less flexible. Informal SDLC requires low customer involvement. But the formal SDLC require customer involvement in various stages of the software development.
Phases in SDLC
No matter what SDLC you select there are a few stages that each of them go through.
- Implementation and maintenance
Popular 8 Models
As we said earlier there are various types of SDLC models but we are only going to discuss 8 of them.
This models moves in a cascade style when it passes through the multiple phases of software development. Every stage has to give certain deliverables. It is closely monitored by the development team and documented. Next phase cannot start until the first one is completed. The software requirements cannot be re-evaluated while in the process.
The team cannot see or test anything until the whole process is completed. This means that if there fare aults in the system the development team cannot do anything about it until the end. The end result is kind of unpredictable. Testing is hasty and mistakes are expensive to fix in this SDLC.
Each stage in this linear model has a corresponding testing activity to undergo. The workflow in this model is organized, controlled and high quality but that also makes it time consuming and very expensive. Mistakes in requirements can be detected early but their correction in the development phase is still hard to fix and costly. Just like in the waterfall model, requirements can be gathered in the beginning but can’t be changed.
Incremental and Iterative Model
The development process in this model is Lego style. It is split in several iterations. In each iteration new modules are added with little or no change in the previous module. The process of software development either goes parallel or sequential. Parallel development is fast while sequential development is long and expensive.
In iterative model the software transforms and grows in each iteration. The iterations keep adding up on the previous ones but the basic design remains the same. The project is delivered in part so there is no requirement of specifications from the start. Besides changes can be made to these specifications in the development process.
But they cannot be changed radically. The main objectives, especially the ones related to design must remain the same. This model requires involvement of customers if amendments are to be made in the requirements in the development process.
This model revolves around risk assessment. That is why if you want to use this model to the fullest, you should hire experts of risk evaluation. The duration of this model is around 6 months normally. It starts with 4 essential activities which are planning, risk analysis, prototype creation and evaluation of previous activities. It repeats in a spiral cycle, which extends the time frame of the project.
This model requires intensive customer involvement. Customers can give their feedback in the review and exploration process. But their amendments are not acceptable in the development stage.
RUP stands for rational unified process. This model is a combination of iterative and linear frameworks. The software development process is divided in four parts in it, which are inception, construction, elaboration and transition. All of the phases are completed in multiple iterations save for the inception. RUP gives you stable and flexible solutions. But it is not as adaptable and fast as Agile group.
There are few models that fall under the Agile umbrella. Agile requires early customer feedback, strong communication and iterative development. Agile group of models takes up to weeks and gives a full solution. They focus less on detailed documentation and more on testing.
The software is developed quickly but the because of the rigorous testing required it takes more time to transfer it to the support team. Since there is no documented software description it takes more time to identify problems when maintenance is required. But Agile continuously updates, changes, evolves and improves its programs. The following are few of the models that come under the Agile group.
- Extreme programming
This is a very famous Agile model. The iterations which are called as ‘sprints usually last 2 to 4 weeks. They are followed by the through assessment of the previous ‘sprint. You can’t make changes to the activities of a sprint once they have been defined.
The iterations in EP last for 1 to 2 weeks. The team can introduce changes to the iteration if they have not started working with an important part of the software. But it does complicate the delivery of the quality of the software.
When it comes to software development there is no one perfect model. In the years of SDLC evolution various models were developed. These models are made for meeting different development expectations and requirements. Some models are simply too expensive to implement and maintain for some people. Many of these models looks alike and cross in the solutions. The 8 that we mentioned here are among the most popular ones.