There are number of different software development methodologies used in the software industry today. Waterfall development method is one of the earliest software development methods. V-Model, RUP and few other linear, iterative and combined linear-iterative methods, which came after waterfall methodology, intended to wipe out many issues of the waterfall method. All these earlier methodologies are called Traditional Software Development Methodologies. Agile model is a more recent software development model introduced to address the shortcomings found in the traditional models. Main focus of Agile is incorporating testing as early as possible and releasing a working version of the product very early, by breaking down the system in to very small and manageable sub parts.
What is Traditional Software Development Methodology?
Software methodologies like Waterfall method, V-Model and RUP are called traditional software development methodologies. Waterfall methodology is one of the earliest software development models. As the name suggests, it is a sequential process in which progress flows through several phases (requirement analysis, design, development, testing and implementation) from top to bottom, analogous to a waterfall. V-Model is considered as an extension of the Waterfall software development model. V-Model uses the same relationships between phases defined in the Waterfall model. But instead of descending linearly (like the Waterfall model) V-Model steps down diagonally and then moves back up (after the coding phase), forming the shape of the letter V. RUP (Rational Unified Process) is an adaptable process framework (not a single concrete process), that can be customized by the development organization according to their needs. Slightly similar to waterfall, it has fixed phases as inception, elaboration, construction and transition. But unlike waterfall, RUP is an iterative process.
What is Agile?
Agile is a very recent software development methodology (or more correctly, a group of methodologies) based on the agile manifesto. This was developed to solve some shortcoming in traditional software development methodologies. Agile methods are based on giving high priority to the customer participation early in the development cycle. It recommends incorporating testing by the customer early and often as possible. Testing is done at each point when a stable version becomes available. The foundation of Agile is based on starting testing from the beginning of the project and continuing throughout to the end of the project. Scrum and Extreme programming are two of the most popular variations of Agile methods.
Key value of Agile is “quality is the team’s responsibility”, which stresses that the quality of the software is the responsibility of the whole team (not just the testing team). One other important aspect of Agile is breaking down the software in to smaller manageable parts and delivering them to customer very quickly. Delivering a working product is an utmost importance. Then the team continues to improve the software and deliver continuously at each major step. This is achieved by having very short release cycles (called sprints in Scrum) and getting feedback for improvement at the end of each cycle. Contributors without much interactions of the team such as developers and testers in the earlier methods, now work together within the Agile model.
What is the difference between Agile and Traditional Software Development Methodology?
Although Agile method is based on iterative development as some of the traditional approaches, Agile and Traditional methodologies have key differences. Traditional approaches use planning as their control mechanism, while Agile models use the feedback from the users as the main control mechanism. Agile can be called a people-centric approach than traditional methods. Agile model delivers a working version of the product very early compared to traditional methodologies so that the customer can realize some of the benefits early on. Testing cycle time of Agile is relatively short compared to traditional methods, because testing is done parallel to development. Most traditional models are very rigid and relatively less flexible than the Agile model. Because of all these advantages, Agile is preferred over the traditional methodologies at the moment.