The spiral model, first described by Barry Boehm in , is a risk-driven software development process model which was introduced for dealing with the shortcomings in the traditional waterfall model. A spiral model looks like a spiral with many loops. The exact number of loops of the spiral is unknown and can vary from project to project. This model supports risk handling, and the project is delivered in loops. Each loop of the spiral is called a Phase of the software development process.
The initial phase of the spiral model in the early stages of Waterfall Life Cycle that is needed to develop a software product. The exact number of phases needed to develop the product can be varied by the project manager depending upon the project risks.
As the project manager dynamically determines the number of phases, so the project manager has an important role to develop a product using a spiral model. Agile is an umbrella term for a set of methods and practices based on the values and principles expressed in the Agile Manifesto that is a way of thinking that enables teams and businesses to innovate, quickly respond to changing demand, while mitigating risk.
Organizations can be agile using many of the available frameworks available such as Scrum, Kanban, Lean, Extreme Programming XP and etc. The Agile movement proposes alternatives to traditional project management. Agile approaches are typically used in software development to help businesses respond to unpredictability which refer to a group of software development methodologies based on iterative development, where requirements and solutions evolve through collaboration between self-organizing cross-functional teams.
The primary goal of being Agile is empowered the development team the ability to create and respond to change in order to succeed in an uncertain and turbulent environment. Agile software development approach is typically operated in rapid and small cycles. This results in more frequent incremental releases with each release building on previous functionality. Thorough testing is done to ensure that software quality is maintained. The output of this model is developed software, that may or may not be according to the requirements of the customer.
Advantages of Big-Bang model Big-Bang model is a simple model. It needs little planning. It is simple to manage. It needs just a few resources to be developed. It is useful for students and new comers. Disadvantages of Big-Bang model It is a very high risk model. This model is not suitable for object oriented and complex projects.
Big-Bang is poor model for lengthy and in-progress projects. It identifies the product that must be tested before release. The testing team find the bugs then sends the software back for fixing.
To deliver the fixes developers complete some coding and send the software again for testing. This process is repeated till the bugs are found in it, at an acceptable level. Advantages of Code-and-fix model This model is suitable for small projects. It needs less project planning. Disadvantages of Code-and-fix model It is difficult to accommodate changes. It is not clear what will be delivered and when. It is difficult to assess quality.
It is widely used in government projects and many vital projects in company. The waterfall model is also called as 'Linear sequential model' or 'Classic life cycle model'. In this model, each phase is executed completely before the beginning of the next phase. Hence the phases do not overlap in waterfall model. This model is used for small projects. Furthermore, the User Interface and User Experience are designed in this step.
Taking into account the target users of the software application and the main features, a user-friendly and modern looking User Interface is designed. The product design layouts further serve as a base for the next step in the development cycle. In the next step, which involves coding, the development team would have to come up with a plan for implementing the programming language.
After the phase of product design, the development team moves on to the stage of coding and implementation. Once the development team has the requirement specification and the design documents in hand, the software developers can start programming. Besides coding, the developers also perform unit or module testing in this phase, as to detect potential problems as early as possible in the development phase.
Some companies prefer to outsource the coding activities, and many times also the previous step of Product Design, to a third-party software development company.
An interesting article about things to consider when outsourcing can be found here. After the coding phase, the team can then move on to the next step of development, which is testing. After the step of coding and implementation, the team can then proceed to integration and validation testing.
Software development service teams are in the constant process of releasing different software applications for various purposes, as such this process is necessary as it is important to test the product against all parameters available vigorously.
This phase exposes potential bugs in the product, and if any, these are corrected. As we saw in the previous step, the software developers themselves will perform unit or module testing. To help you decide, here are 5 of the best software development processes with pros and cons for each. In its most basic form, you can think of the Waterfall method as following each step of the SDLC in sequence—you have to finish each one sequentially before moving on. However, in most practical applications the phases overlap slightly, with feedback and information being passed between them.
Due to its rigid structure and big up-front planning time, the Waterfall software development process works best when your goals, requirements, and technology stack are unlikely to radically change during the development process such as during shorter one-off projects. In more practical terms, the Waterfall process is best suited for larger organizations like government agencies that require sign-offs and documentation on all requirements and scope before a project starts. And because of this, unless your scope is tightly written, you might end up committing to the wrong path without knowing it until launch day.
The Agile software development process and its most popular methodology, Scrum opt for an iterative and dynamic approach to development. This allows tighter feedback loops throughout the software development process so you can adapt and react to real customer needs. Thanks to its dynamic and user-focused nature, Agile is the software development process favored by most startups and technology companies testing new products or doing continuous updates to long-standing ones. As it becomes easier to do small releases and gather user feedback, Agile allows companies to move faster and test theories without risking their entire livelihood on a major release their users hate.
Additionally, using Agile and Scrum takes dedication and a solid understanding of the underlying process to pull off properly. The incremental and iterative software development processes are a middle-ground between the structure and upfront planning of the Waterfall process and the flexibility of Agile.
While both follow the idea of creating small bits of software and exposing them to users for feedback, they differ in what you create during each release. Think of it like coming up with an overall plan, building an MVP with only the core functionality, and then adding features based on feedback. In the Iterative software development process, however, each version you release includes a version of all your planned features. Think of it like building a v0.
Both of these add a certain level of flexibility to your software development process without throwing an overall plan out the window, making them ideal for large projects with defined scopes or teams with less risk tolerance. With the incremental process, you get early feedback on your core feature, which can help you validate your business case right away.
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