Software Development Models – The Beginner’s Guide
Demand for software is on the rise, despite the blow dealt by the pandemic. Thus, actual and forecast data for global spending on software from Statista suggest a bright future for software companies. Indeed, global spending on enterprise software reached $425 billion U.S. in 2020. To meet this demand, software companies use different software development models. We will explain seven such models and their impact on the speed and cost of delivery. First, let us explain what software development model means. Such a model is a set of tools, processes, and methodologies selected to develop the project based on project goals. It aims at boosting productivity while reducing operating costs. Thus, the software development model you choose can make or break your project. Next, we will go through the software development life cycle (SDLC) stages and their impact on your choice of software development models.
An Overview of the Software Development Lifecycle
The software development lifecycle covers all the stages of producing a software solution. In short, it goes from requirement analysis to deployment and support and depends on the model you choose. We will briefly present these phases next.
At this stage, the software and business experts gather the information needed to define the business objectives for the product. Then, they prepare the software specifications, which is a document with the main functional requirements for the software. All the resulting information helps develop a product aligned with the client’s business objectives.
Architecture and Design
The software development team produces a document that indicates how to develop the product. The document covers frameworks, platforms, and delivery estimates. Then, the development team shares the documentation and a high-level visual representation of the product with all the parties involved in the development process.
This stage is the core of the software development process. The development team writes the code according to the requirements and does plenty of fine-tuning. In short, the development stage produces the software requested by the client.
At this stage, the software engineers check the code and make sure the various modules of the software work together as intended. Software testing is a continuous process, especially in the Agile model. It may include different types of functional and non-functional testing. For example, integration, system, and sanity testing belong to the former category, while performance and usability testing to the latter.
In short, professional software development companies test all the product aspects in what is known as continuous testing.
At this stage, the software development company rolls out the application, making it available on the market. Deployment happens after the final testing and approval of the project by the delivery team and the client. Simply put, software deployment includes all the activities that make a software solution available to the users.
Maintenance and Support
Most software applications require ongoing maintenance to keep their relevance for the users and remain competitive. For this purpose, software companies monitor, upgrade and optimize the software. Furthermore, they fix bugs detected after deployment. In short, software maintenance ensures the software meets the evolving customer needs.
The Importance of Following the Software Development Process
By following the process outlined before, companies can keep the software project on schedule and within budget. First, by doing that, they make sure the project stays on track. The process makes defining clear objectives and monitoring them easy. Furthermore, it helps managers and clients with resource planning and allocation. In addition, the process emphasizes productivity. Thus, software development models like Agile allow companies to make the most of each specialist and resource allocated to the project. The same goes for DevOps practices, which significantly increased productivity for 59 percent of the IT organizations that adopted them.
Finally, following the development process by the book can have a strong impact on development time and improve management. Team members and the client will work well together. Furthermore, applying the right development model to the project can lead to a six-fold reduction in development time.
Brief Presentation of the Software Development Models
The Waterfall Model for Software Development
The Waterfall model was the first structured approach proposed for software development services. The model allows no overlap between different stages of the process. Thus, the team must complete each stage before starting the next one. As its name suggests, the Waterfall approach takes the stages in order, from analysis to development and testing to maintenance. Furthermore, it has clear goals, milestones, and deliverables for each stage. Moving to the next stage is only possible after meeting the goals for the current one and with written approval. The rigidity of this software development model makes any adjustments difficult and costly. Simply put, the team can fix any errors only in the maintenance stage, regardless of when they found them. With unclear or complicated requirements, the Waterfall model is quite risky. Thus, the model can work well for small projects with few requirements.
The visual representation of the waterfall model presents a major disadvantage. The sequence of stages and activities it shows suggests that developers must take the stages in the given sequence without returning to previous stages. Thus, quality suffers. To address this issue, the V-Model connects the development and testing stages. Also known as the Validation and Verification model, the V-Model resembles Waterfall, except for planning the testing early in the process. Thus, each stage in development has its corresponding testing activity. Verification includes requirement analysis, system design, architecture or high-level design, and coding. When the coding is over, the validation starts, and the model pivots and ascends to form a “V” shape. This part includes unit, integration, system, and user acceptance testing.
The Iterative Model for Software Development
The Spiral Model
The spiral model provides support for risk handling. Graphically, the model looks like a multi-looped spiral, with each spiral representing an iteration. Each iteration includes four stages, shown graphically in separate quadrants. First, the team sets objectives and identifies alternative solutions at the start of every phase. For that, it relies on the requirements it gathers from the customer. Then, they propose alternative solutions for that phase. In the second stage, the team evaluates the possible solutions. Then, they identify the risks for each solution, mitigate them, and build the prototype for the best solution. Mitigating the unknown risks of the project is best achieved with a prototype. In the third quadrant, the team develops and tests the next product version. Last, the customer reviews the software’s current version, and then the team starts planning the next phase.
The Prototyping Model for Software Development
Prototyping means developing incomplete but functional versions of a software program. A prototype is a basic representation of the product and allows customers to test their ideas with little investment. The goal of the prototyping software development model is to build, test, and refine a prototype until achieving an acceptable result. Furthermore, it creates the basis for full-scale software or system. This model is iterative, based on trial and error, and requires a strong involvement of the client. In short, the prototyping model can significantly reduce the number of iterations in the software development cycle. Besides, it works best when the project team has very few details about the product at the project’s onset. The prototyping model includes:
- requirement gathering and analysis,
- quick design,
- building a prototype,
- initial user evaluation,
- refining the prototype and
- product implementation and maintenance.
The Agile Scrum Software Development Model
Agile Scrum is an incremental model for software development. It focuses on customer involvement, feedback, and adjustments. In short, the Agile Scrum methodology combines the Agile mindset with the Scrum framework to deliver the highest value to stakeholders. While Agile stands for incremental, Scrum breaks projects into small parts called “sprints.” Scrum replaced the traditional phases of software projects with sprints and releases. Unlike non-iterative models, which build the entire product in a single process, Scrum produces a fully functional system at the end of each sprint. Thus, the Agile Scrum project management system is an incremental approach consisting of two- to four-week sprints. In each sprint, the team builds the key features of a potentially deliverable product. Sprint after sprint, the development team adds features to the product and incorporates customer feedback. Agile Scrum works great for complex projects and changing environments.
The Kanban Model
Like Scrum, Kanban is also an Agile model. In Japanese, “kanban” means “visual board,” a concept that is one of the two distinctive features of the model. The second is the lack of apparent iterations. Thus, even when the model includes iterations, they often last no more than a day. Furthermore, Kanban relies on real-time communication and visibility of the work items for the entire team. With Kanban boards, managers can standardize the team’s workflow, identify, and fix blockers and dependencies. The simplest project workflow in Kanban includes the To Do, In Progress, and Done steps. As multitasking distracts people, a fundamental rule with Kanban is to limit the amount of work in progress. Even so, setting and meeting deadlines prove difficult with this method. Furthermore, not having a planning stage lets the team make changes at any time. Thus, Kanban may not work for big, complex projects.
We briefly introduced you to some of the best-known and popular software development methodologies. While all of them have strengths and weaknesses, the linear models have lost ground to the agile methodologies lately. Even so, there is no model suited for any project. Based on the project size, type, and complexity, on technical or team considerations, each of the existing methodologies may be best suited. The Waterfall model, for example, has failed to deliver on several large-scale government projects. However, it is still appropriate for projects with clear objectives and solutions and no pressure for immediate implementation. The V-shaped model works well for small to medium-sized projects with clearly defined and fixed requirements. Besides, the model relies on abundant technical resources and their technical expertise. The spiral model works well for large, complex, and expensive projects, while Scrum handles change and uncertainties like no other.