Software Development

Software Development Life Cycle is a process used by software industry to design, develop and
test high quality softwares. The SDLC aimsto produce a high 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.
The 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 organization. It consists of a detailed plan
describing how to develop, maintain, replace and alter or enhance specific software. The life cycle defines a
methodology for improving the quality of software and the overall development process.

A typical Software Development life cycle consists of the following stages:

Stage 1: Planning and Requirement Analysis : Requirement analysis is the most important and fundamental
stage 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. This 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 stage. The 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.

Stage 2: Defining Requirements : Once the requirement analysis is done the next step is to clearly define and
document the product requirements and get them approved from the customer or the market analysts. This is
done through ‘SRS’ – Software Requirement Specification document which consists of all the product
requirements to be designed and developed during the project life cycle.

Stage 3: Designing 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 design approach for the product architecture is proposed and documented in a DDS – Design
Document Specification. This DDS is reviewed by all the important stakeholders and based on various
parameters as risk assessment, product robustness, design modularity , budget and time constraints , the
best design approach is selected for the product. A design 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). The internal design of all the modules of the proposed architecture should be
clearly defined with the minutest of the details inDDS.

Stage 4: Building or Developing the Product : In this stage of SDLC the actual development starts and the
product is built. The programming code is generated as per DDS during this stage. If the design is performed in
a detailed and organized manner, code generation can be accomplished without much hassle. Developers
have to follow the coding guidelines defined by their organization and programming tools like compilers,
interpreters, debuggers etc are used to generate the code. Different high level programming languages such
as C, C++, Pascal, Java, and PHP are used for coding. The programming language is chosen with respect to the
type of software being developed.

Stage 5: Testing the Product : This stage is usually a subset of all the stages as in the modern SDLC models, the
testing activities are mostly involved in all the stages of SDLC. However this stage refers to the testing only
stage of the product where products defects are reported, tracked, fixed and retested, until the product
reaches the quality standards defined in the SRS.

Stage 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 stages as per the
organizations’ business strategy. The product may first be released in a limited segment and tested in the real
business environment (UAT- User acceptance testing).Then based on the feedback, the product may be
released as it is or with suggested enhancements in the targeting market segment. After the product is
released in the market, its maintenance is done for the existing customer base.

SDLC Models

There are various software development life cycle models defined and designed which are followed during
software development process. These 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

The other related methodologies are Agile Model, RAD Model – Rapid Application Development and
PrototypingModels.