Software Development Life Cycle (SDLC) is the term used to describe the sequence of activities and tasks within the software development process.
The classic SDLC consists of six main stages, which any software product goes through:
- Quality Assurance
- Support & Maintenance
At each stage, different actions are required, but all of them are aimed at achieving the same goal: to create an efficient, cost-effective and high-quality software product.
The first SDLC stage is the analysis of the technical and business requirements imposed on the end product. The definition of detailed requirements will guarantee that the tasks will be set correctly and in practice, you will get exactly what you need.
At this stage, it is necessary to receive information from all parties of interest: customers, developers, project managers and end users.
You need to get answers to the following questions:
- What tasks should the product cope with?
- What resources are available?
- Who will use the system and which way?
- What are the ways to solve the problems?
- What risks can you face during the implementation process?
In addition to identifying requirements for the software product, this stage involves their systematization, documentation, analysis and, if necessary, adjustment.
All the obtained details of the future software may be stored in the document called Software Requirements Specification (SRS), which is, if absolutely flawless and well-defined, to be a guidebook for development team.
After getting a good grasp of the basic technical requirements, the design stage begins. At first, it can be a simple prototype, which shows the shape of the system in general, and then you can proceed to create low-fidelity wireframes.
The design stage helps to create the overall architecture of the system and determine which technologies and programming languages you will be using for the project development. And understanding how the system will look and function allows you to identify hardware and system requirements. In general, all is laid down in a special document: Design Specification Document (DSD).
The functional requirements for the interface are to be determined, for example, the types of data received, input mediums, user interaction logic, etc. It is at this stage that the initial idea begins to develop into a functioning system.
After approving the product requirements and design, there is a transition to the next stage of the lifecycle: implementation or development of functional end. Here we start coding, based on previously formed documentation (SRS). Therefore, this SDLC stage takes the longest.
If hardware is used, this stage also includes configuring and adjusting the equipment in order to fulfil specified technical requirements. The client can already see the product in operation and assess its compliance with the original specification.
Developers can use different approaches to implementation, depending on the size of the project and resources availability. For larger enterprise projects, Waterfall (project development methodology) is a good choice, and for smaller ones, where flexibility comes first – Agile methodologies are preferred.
4. Quality Assurance
The purpose of the quality assurance stage (or testing phase) is a detection and documentation of bugs made at the design stage. Developers use the bug report to eliminate them. Later a QA expert tests the product again and again not only to check whether the problem is fixed or not, but also to make sure that in the process of eliminating the previously described bug new ones have not appeared.
At this stage, all types of functional tests are performed in order to check the product compliance with all the initial technical and functional requirements. Work on the elimination of bugs continues until the product functionality fully meets the original specification.
Testing can be performed by a special team of employees or real users (sometimes called Beta testers) and additionally divided into manual or automated testing. The main goal is to make sure that real results of the software performance is up to a desired ones.
In light of the need to satisfy end users and provide them with a positive experience, testing becomes an increasingly important stage of the software development life cycle.
The deployment stage begins once the system has been tested and recognized as being ready for real operating. The complexity of deployment is determined by the scope of the project work, so it can be realized as either a one-time release or step-by-step launch. In this case, all begins with one module, and then the rest are gradually added.
Such method as beta testing was widely used as well. That is the release initially positioned as a beta version, and if users (or clients) find errors or a malfunction in individual functional elements in the process of its use, they report them to the developers. Based on the feedback, engineers make all necessary changes or correct errors, and later the final deployment takes place.
6. Support & Maintenance
When customers begin utilizing the finished product in real life, various problems occasionally appear, which need to be dealt with in order to maintain the system performance. Also, occasional technical support of the system is needed in order to maintain its relevance in terms of technologies and modern standards.
At least it is necessary in order to minimize security threats. Also, a technical maintenance team helps to collect and systematize various performance indicators of the software in real time mode.
Regular error correction and system improvement help to make the software better, so that it is up to the requirements and expectations of users as much as possible. In the real world, the environment is constantly changing, and no matter how ideal the original plan seemed to be, rarely it remains the same when faced with reality.
When applied, the software development life cycle can assure a high quality standard of the project implementation, while reducing the resource cost to the lowest possible. The SDLC stages listed in this article are used in all development approaches, only their duration and sequence differs.
By organizing the system for working on the product as several sequential steps, we can be sure that after launching the final release, our client and target audience will get exactly what they want to. This is the main argument for applying the above mentioned in practice.