SDLC in a nutshell
Created in 1960, the Software Development Life Cycle—or SDLC—is an outline for high-quality software production. It describes the stages of software development—and the order they go in. There are six distinct SDLC phases:
- Planning
- Analysis
- Design
- Development and testing
- Implementation
- Evaluation and maintenance
Those phases create a handy acronym: PADDIE. We’ll come back to PADDIE later on.
Why use an SDLC model?
Developers use SDLC to create programs that perform well. A well-implemented SDLC procedure promotes understanding within a development team, enables full management control and documents the creative process from start to finish. Everyone involved in the project agrees to a set of goals from the get-go, and everyone understands the costs involved.
Without an SDLC procedure in place, teams run the risk of going over budget, producing programs that don’t work properly and disappointing their customers. In contrast, when developers use a robust SDLC methodology, they lower the overall cost of software development by working quickly and efficiently.
Six solid SDLC methodologies
Six main SDLC methodologies exist. They’re all logical and efficient processes, but they each follow slightly different paths. Let’s explore them in a bit more detail.
Agile
Published in 2001, the Manifesto for Agile Software Development forms the core of today’s Agile SDLC methodology. Based on collaborative decision making between requirements and solutions teams, the Agile methodology is a popular and effective SDLC model. Some organizations apply the Agile methodology to non-tech ventures, too.
The Agile methodology works a little bit like multivariate testing, which is a common website optimization technique. In essence, the Agile model encourages “fast failure.” Developers produce ongoing release cycles, each slightly different from the last, to optimize beta software. Small problems never have the chance to turn into big problems, and clients stay engaged throughout.
Many development teams apply a framework called Scrum within the Agile methodology. Scrum teams, led by a ScrumMaster, complete assigned tasks in weeks-long sprint sessions. Daily Scrum meetings keep them on track.
DevOps
One of the newest SDLC methodologies, DevOps is basically a fusion of the Agile and Lean methodologies. It’s a collaborative model, just like Agile, in which the development and operations teams work closely with one another. This collaboration helps make software production more efficient, so programs reach the market sooner.
A fast-paced model, DevOps relies heavily on development process automation as well as continuous feedback and team discipline. Frequent incremental changes to beta software, combined with a forward-thinking approach to infrastructure management, produce quick results. Many people who subscribe to the DevOps approach consider the model a philosophy, rather than a traditional development methodology.
Iterative
The Iterative methodology is all about repetition. Cast your mind back to primary school for a moment: Remember writing out your spelling words 10 times over? This is the development equivalent to that approach. Iterative development teams begin with a set of software requirements, which they test and evaluate repeatedly. Then, they incorporate changes into a new version, or iteration, of the program they’re working on.
Teams following the Iterative methodology usually produce working software quite early in the SDLC process. On the other hand, the repetitive processes involved in the Iterative model consume significant resources.
Big names employ the Iterative methodology to get ahead. One example is IBM, which uses the Rational Unified Process (RUP)—an in-house productivity boosting model suitable for use in a wide range of circumstances.
Lean
The word “lean” implies a streamlined process—and that’s exactly the point of the Lean methodology. Developers who choose the Lean model use a set of simplified production processes to achieve swift progress. The seven Lean principles encourage teams to:
- Eliminate waste
- Integrate quality
- Kindle knowledge
- Defer commitment as much as possible
- Deliver results quickly
- Respect other people
- Optimize the entire program
Lean teams don’t multitask: Instead, they select the most pressing tasks and tackle them on the spot. Developers continuously look for opportunities to improve software and incorporate those ideas as they go along. Unnecessary meetings simply don’t happen, and bloated documentation processes give way to simpler, clearer communication procedures.
Spiral
The Spiral methodology takes inspiration from the Iterative model. Like the Iterative model, the Spiral methodology uses repetition to achieve quick results. Projects repeatedly pass through these four process stages:
- Planning
- Risk analysis
- Engineering
- Evaluation
Programs are refined each time they pass through the “spiral,” and eventually, they become fully optimized. Teams use risk management to highlight potential problems in advance.
Organizations typically use the Spiral methodology for larger projects. Using the Spiral method, teams build highly customized programs and weave user feedback into the software early on.
Waterfall
Arguably the oldest SDLC model on record, the Waterfall methodology is pretty straightforward. In short, teams finish one stage and then begin the next—and there’s no going back. Once a phase is finished, the door is shut, and the entire development crew moves on. Each stage gets its own project plan, which incorporates information from the previous stage.
Waterfall model advantages include its stoic approach to software production. The biggest disadvantage of the Waterfall methodology is its inflexibility. There isn’t much wiggle room in a Waterfall approach: Problems get sorted out in the maintenance stage at the very end, which can be frustrating if they’re spotted earlier.
Organizations dealing with known requirements find the Waterfall model reassuring and reliable. Those with unknown or changeable needs tend to choose alternative SDLC methodologies.
What are the steps in the SDLC methodology?
Remember PADDIE? Regardless of model, all SDLC methodologies include the same six stages. Let’s look at each PADDIE phase in detail.
Stage 1: Planning
The planning stage is the information-gathering phase. Project managers and their teams communicate with clients and stakeholders to find out what their needs are. Client questions for the planning stage include:
- Who will use the software?
- What types of input data will the software tackle?
- What do you want the software to do?
Other parts of the planning stage include a feasibility assessment and, finally, a basic project plan.
Stage 2: Analysis
In the analysis stage, developers take the information gathered during the planning stage and use it to create an action plan. Programmers analyze business requirements—in other words, the client’s needs—and create a set of process diagrams that show what the finished software will do.
Stage 3: Design
The SDLC design phase has two distinct parts: IT infrastructure design and interface design. Developers specify essential hardware—servers, for example—and define compatible operating systems—smartphones, computers and so forth. Then, they design the software’s system architecture, otherwise known as the backend. After that, they design the software’s frontend, which is also known as its user interface.
Stage 4: Development and testing
This is the building phase—the bit where all the coding Lego comes together. Some teams treat development and testing as a single phase, while others break it into its constituent parts. This stage involves actual coding, so it’s the most important part of the entire SDLC methodology. It’s usually also the longest SDLC phase.
Various types of testing happen at this point, including:
- Acceptance testing
- Integration testing
- System testing
- Unit testing
- Non-functional testing
Stage 5: Implementation
Working software in hand, development teams move on to the implementation, or delivery, phase. The system gets deployed in the client environment, and end users begin to beta test the software. Data and components associated with program development go into the production phase at this stage.
Stage 6: Evaluation and maintenance
This is the aftercare phase. Clients and developers alike analyze data gathered by the software to see if it functions as intended. Patches and upgrades hone the program so that it performs optimally—even under demanding conditions. New users receive support as they get used to the system, which continually adapts to the business’s needs.
SDLC hiring tips
Assuming you’re not already an IT company, you’ll need an SDLC-centric team to help you develop and hone custom software for your business—or for outside clients. Potential roles include:
- Project manager
- Business analyst
- Software engineer/developer
- Designer
- Quality engineer
- Release manager
If you’re hiring new individuals, choose team-focused candidates with suitable qualifications and relevant work experience. SDLC candidates should be:
- Willing to work with code written by other people
- Able to write high-quality, accurate code
- Good at solving problems
- Optimistic and imaginative
- Honest and technologically adaptable
A final word on SDLC methodology
SDLC best practices help streamline software development, ensure programs meet end users’ needs and deliver value and quality to clients. Six main SDLC methodologies exist: The resources you have at your disposal—and your client’s needs—will determine which one you choose. The right development team can make all the difference, so make sure you hire quality applicants who work well together, stay upbeat and write great code.
