System Development Life Cycle (SDLC) Ashima Wadhwa Assistant Professor(giBS)

What is SDLC?  It is a conceptual model used in project management that describes the stages involved in an information system development project. Basically, SDLC consists of all the steps/stages of software starting from its inception to its implementation. There are in fact numerous types of SDLC models (Agile, Waterfall et al) and depending upon your requirements you can choose any of them to meet your purpose.

Waterfall Model

Requirement Gathering and Analysis: Requirement gathering and analysis is the first stage of any SDLC model. This phase is basically the brainstorming phase and often consists of sub-stages like Feasibility Analysis to check how much of the idea can be put into action.

Requirement Analysis In the Analysis stage an in-depth analysis is performed to obtain a detailed understanding of the business needs. Tools Used: DFD’s, interviews, on-site observation, questionnaire etc. Training, experience and common sense are required for collecting information to do analysis.

Feasibility Study Economic: Cost benefit analysis. Technical: We need to check whether existing computer can support the system. Behavioral: An estimate should be made of how strong a reaction the user staff is likely to have toward the development of a computerized system.

System Design It is the most creative and challenging phase of SDLC. It defines the final system and refers to the technical specifications. DFDs are used to show the flow of system. Two phases: 1. Logical Design and Physical Design Logical Design: Specifies user needs. Physical Design: Tells the programmer what the candidate system must do.

Coding As the name implies, in this stage the software is coded with precision. A team of programmers are assigned by the company to work on the software. More often than not, the work is sub- divided under a sub-phase called Task Allocation, where each developer is assigned a part of the work depending on his or her skill set(s). This helps complete the coding efficiently.

Testing When the software is ready, it is sent to the testing department where Quality Analysts test it thoroughly for different errors by forming various test cases. They either test the software manually or using automated testing tools and ensure that each and every component of the software works fine. Once the QA makes sure that the software is error-free, it goes to the next stage, which is Implementation.

Implementation Less creative then designing phase. It is of 3 types: Implementation of a computer system to replace a manual system. Implementation of a new computer system to replace an existing one. Implementation of a modified application to replace existing one on same computer. Parallel Runs: In this new system runs with old system which provides assurance, and even helps user staff gain experience.

Post Implementation The Post-Implementation Review is used to evaluate the effectiveness of the system. The objectives are to determine if the system does what it is designed to do Does it support the user as required in an effective and efficient manner The review should assess how successful the system is in terms of functionality, performance, and cost versus benefits.

Maintenance The emphasis during this phase is to ensure that needs continue to be met and that the system continues to perform according to specifications. Routine hardware and software maintenance and upgrades are performed to ensure effective system operations. User training continues during this phase, as needed, to acquaint new users to the system or to introduce new features to current users.

Queries?