Sdlc Overview

SDLC, Software Development Life Cycle is a process used by software industry to desig n, develop and test hig h quality softwares. T he SDLC aims to produce a hig h quality software that meets or exceeds customer expectations, reaches completion within times and cost estimates. SDLC is the acronym of Software Development Life Cycle. It is also called as Software development process. T he software development life cycle (SDLC) is a framework defining tasks performed at each step in the software development process. ISO/IEC 12207 is an international standard for software life-cycle processes. It aims to be the standard that defines all the tasks required for developing and maintaining software. What is SDLC? SDLC is a process followed for a software project, within a software org anization. It consists of a detailed plan describing how to develop, maintain, replace and alter or enhance specific software. T he life cycle defines a methodolog y for improving the quality of software and the overall development process. T he following fig ure is a g raphical representation of the various stag es of a typical SDLC. A typical Software Development life cycle consists of the following stag es: Stag e 1: Planning and Requirement Analysis Requirement analysis is the most important and fundamental stag e in SDLC. It is performed by the senior members of the team with inputs from the customer, the sales department, market surveys and domain experts in the industry. T his information is then used to plan the basic project approach and to conduct product feasibility study in the economical, operational, and technical areas. Planning for the quality assurance requirements and identification of the risks associated with the project is also done in the planning stag e. T he outcome of the technical feasibility study is to define the various technical approaches that can be followed to implement the project successfully with minimum risks. Stag e 2: Defining Requirements Once the requirement analysis is done the next step is to clearly define and document the product requirements and g et them approved from the customer or the market analysts. T his is done throug h .SRS. . Software Requirement Specification document which consists of all the product requirements to be desig ned and developed during the project life cycle. Stag e 3: Desig ning the product architecture SRS is the reference for product architects to come out with the best architecture for the product to be developed. Based on the requirements specified in SRS, usually more than one desig n approach for the product architecture is proposed and documented in a DDS - Desig n Document Specification. T his DDS is reviewed by all the important stakeholders and based on various parameters as risk assessment, product robustness, desig n modularity , budg et and time constraints , the best desig n approach is selected for the product. A desig n approach clearly defines all the architectural modules of the product along with its communication and data flow representation with the external and third party modules (if any). T he internal desig n of all the modules of the proposed architecture should be clearly defined with the minutest of the details in DDS. Stag e 4: Building or Developing the Product In this stag e of SDLC the actual development starts and the product is built. T he prog ramming code is g enerated as per DDS during this stag e. If the desig n is performed in a detailed and org anized manner, code g eneration can be accomplished without much hassle. Developers have to follow the coding g uidelines defined by their org anization and prog ramming tools like compilers, interpreters, debug g ers etc are used to g enerate the code. Different hig h level prog ramming lang uag es such as C, C++, Pascal, Java, and PHP are used for coding . T he prog ramming lang uag e is chosen with respect to the type of software being developed. Stag e 5: Testing the Product T his stag e is usually a subset of all the stag es as in the modern SDLC models, the testing activities are mostly involved in all the stag es of SDLC. However this stag e refers to the testing only stag e of the product where products defects are reported, tracked, fixed and retested, until the product reaches the quality standards defined in the SRS. Stag e 6: Deployment in the Market and Maintenance Once the product is tested and ready to be deployed it is released formally in the appropriate market. Sometime product deployment happens in stag es as per the org anizations. business strateg y. T he product may first be released in a limited seg ment and tested in the real business environment (UAT - User acceptance testing ). T hen based on the feedback, the product may be released as it is or with sug g ested enhancements in the targ eting market seg ment. After the product is released in the market, its maintenance is done for the existing customer base. SDLC Models T here are various software development life cycle models defined and desig ned which are followed during software development process. T hese models are also referred as "Software Development Process Models". Each process model follows a Series of steps unique to its type, in order to ensure success in process of software development. Following are the most important and popular SDLC models followed in the industry: Waterfall Model Iterative Model Spiral Model V-Model Big Bang Model T he other related methodolog ies are Ag ile Model, RAD Model, Rapid Application Development and Prototyping Models.