Software Development Life Cycle, SDLC for short, is a well-defined,
structured sequence of stages in software engineering to develop the
intended software product.
SDLC Activities
SDLC provides a series of steps to be followed to design and develop a
software product efficiently. SDLC framework includes the following
steps:
Communication
This is the first step where the user initiates the request for a
desired software product. He contacts the service provider and tries to
negotiate the terms. He submits his request to the service providing
organization in writing.
Requirement Gathering
This step onwards the software development team works to carry on the
project. The team holds discussions with various stakeholders from
problem domain and tries to bring out as much information as possible on
their requirements. The requirements are contemplated and segregated
into user requirements, system requirements and functional requirements.
The requirements are collected using a number of practices as given -
- studying the existing or obsolete system and software,
- conducting interviews of users and developers,
- referring to the database or
- collecting answers from the questionnaires.
Feasibility Study
After requirement gathering, the team comes up with a rough plan of
software process. At this step the team analyzes if a software can be
made to fulfill all requirements of the user and if there is any
possibility of software being no more useful. It is found out, if the
project is financially, practically and technologically feasible for the
organization to take up. There are many algorithms available, which
help the developers to conclude the feasibility of a software project.
System Analysis
At this step the developers decide a roadmap of their plan and try to
bring up the best software model suitable for the project. System
analysis includes Understanding of software product limitations,
learning system related problems or changes to be done in existing
systems beforehand, identifying and addressing the impact of project on
organization and personnel etc. The project team analyzes the scope of
the project and plans the schedule and resources accordingly.
Software Design
Next step is to bring down whole knowledge of requirements and
analysis on the desk and design the software product. The inputs from
users and information gathered in requirement gathering phase are the
inputs of this step. The output of this step comes in the form of two
designs; logical design and physical design. Engineers produce meta-data
and data dictionaries, logical diagrams, data-flow diagrams and in some
cases pseudo codes.
Coding
This step is also known as programming phase. The implementation of
software design starts in terms of writing program code in the suitable
programming language and developing error-free executable programs
efficiently.
Testing
An estimate says that 50% of whole software development process
should be tested. Errors may ruin the software from critical level to
its own removal. Software testing is done while coding by the developers
and thorough testing is conducted by testing experts at various levels
of code such as module testing, program testing, product testing,
in-house testing and testing the product at user’s end. Early discovery
of errors and their remedy is the key to reliable software.
Integration
Software may need to be integrated with the libraries, databases and
other program(s). This stage of SDLC is involved in the integration of
software with outer world entities.
Implementation
This means installing the software on user machines. At times,
software needs post-installation configurations at user end. Software is
tested for portability and adaptability and integration related issues
are solved during implementation.
Operation and Maintenance
This phase confirms the software operation in terms of more
efficiency and less errors. If required, the users are trained on, or
aided with the documentation on how to operate the software and how to
keep the software operational. The software is maintained timely by
updating the code according to the changes taking place in user end
environment or technology. This phase may face challenges from hidden
bugs and real-world unidentified problems.
Disposition
As time elapses, the software may decline on the performance front.
It may go completely obsolete or may need intense upgradation. Hence a
pressing need to eliminate a major portion of the system arises. This
phase includes archiving data and required software components, closing
down the system, planning disposition activity and terminating system at
appropriate end-of-system time.