What is SDLC (Software Development Life Cycle)

SDLC - Software Development Life Cycle :

Software products, which don’t happen to be user friendly just, don’t find any place in a highly competitive market of this modern era, although they might have been developed with the help of the best available technology. The ease of use of the product is of paramount importance compared to its internal technology, which the customer is not going to see.

Thus for the creation of Innovative Software products, the Development Life Cycle undergoes six phases like:

1) Initial Phase 

2) Analysis Phase

3) Design phase

4) Coding Phase

5) Testing Phase

6) Delivery and Maintenance phase

Phase – 1: Initial Phase: Involves Interaction with the customer and capturing all the requirements.

Personnel Involved: 1) Business Annalist – BA & 2) Engagement Manager - EM

Process Involved: This phase begins with a technical meeting between the Business Analyst & the customer. The Business Analyst (BM) understands all the requirements from the customer & prepares comprehensive requirements document with the help of standard templates & check sheets used by the company. The requirements document forms the basis for further study & action by the Engagement Manager (EM). 

The Engagement Manager tries to hunt for extra requirements if any, which might not be apparent immediately but might involve extra cost. To resolve ambiguous requirements if any, the Engagement Manager organizes demonstration of a prototype if necessary. Such action of quick demonstration of a prototype, which is nothing but a rapidly developed model for the customer is found extremely helpful to remove ambiguities from the requirements on one hand & help winning the confidence of the customer on the other.

Ultimate objective of this phase is to prepare a most comprehensive customer requirements document. Many companies call it with different names like: 

# BRS: Business Requirement Specification.

# FRS: Functional Requirement Specification.

# URS: User Requirement Specification.

# CRS: Client / Customer Requirement Specification.

# BDD: Business Design Document.

# BD  : Business Document.

Depending upon the system followed by various companies, sometimes a single document is maintained, while some companies may go in for two documents. In this case, Broad / outlining information is recorded in the BRS (Business Requirement Specification), while detailed information is recorded in FRS (Functional Requirement Specification).

                                    

Phase – 2: Analysis Phase: Involves Feasibility Study, Broad Planning, Technology selection, Requirement analysis etc.

Personnel Involved: 1) System Annalist – SA, 2) Project Manager – PM & 3) Team Manager -TM

Process Involved: To understand the nature of the program to be developed, the System Annalist focuses on understanding the information domain of the software, its necessary functions, behaviors, performance and necessary interfaces etc. The major objective of the analysis phase is to find out the need and to define the problem, which needs to be solved.

The process covers four distinct analytical operations like:

1) Feasibility Study: Involves detailed study of all the requirements to ascertain as to whether it is possible to meet all the requirements or not. There may be a need for the development team to visit the customer place for study of their system. They development team may investigate the need for possible software automation within the boundaries of the given system. 

2) Broad Planning: Involves an outline document on planning of all resource and time wise planning.

3) Technology Selection: Involves identification, analysis & compilation of various tools & technologies, which would be needed to accomplish the project successfully.

4) Requirement analysis: Involves identification & compilation of various requirements of human resources, hardware & software, which would be needed to accomplish the project successfully.

Ultimate objective of this phase is to prepare a most comprehensive document called SRC or Software Requirement Specification.

Phase – 3: Design Phase: Involves hard core design activities like 1) HLD - High Level Designing & 2) LLD - Low Level Designing

Personnel Involved: 1) Chief Architect – CA is responsible for High Level Designing, 2) Technical Lead – TL is responsible for Low Level Designing

Process Involved: The Chief Architect – CA, starts The entire designing process. This involves subdivision of the entire project into various modules & the process is adequately explained with the help of flow charts & diagrams. Thereafter, the Technical Lead – TL further subdivides these main Modules into sub modules with the help of Unified Modeling Language - UML. The technical lead is responsible for creating the Pseudo Code which is a comprehensive set of instructions written in English language & are meant for guiding the actual code developers.

Ultimate objective of this phase is to prepare a Technical Design Document - TDD.

Phase – 4: Coding Phase: Involves actual Programming or Coding.

Personnel Involved: Code Developers or Programmers 

Process Involved: The design needs to be translated into a machine-readable form. There comes the process of code generation. With the help of Pseudo Code written by the Technical Lead – TL during the Design Phase, Developers carry out the development of the actual source code. The entire coding process is bound by stipulated coding standards defined by the company.

Ultimate objective of this phase is to prepare a Source Code Document - SCD.

Phase – 5: Testing Phase: Involves rigorous testing of the application developed by the programmers.

Personnel Involved: Testing Engineers. 

Process Involved: Different testing methodologies are practiced to detect the software bugs, which happen to take birth during the previous phases. Various testing tools and methodologies are available these days. Some companies create their own testing tools, which are custom made to suit their own development functions.

# In fact the testing process begins right from the customer requirement document. A good test engineer starts his work by thorough study of the requirement document. In case of any doubt arising during understanding of customer requirements, the test engineer raises a Review Report –RR, which contains details of all the doubts.

# Having clarified all the doubts & ambiguities, and after having a thorough understanding of the requirements, the test engineer shall write the test cases with the help of company specific test case templates.

# Execution of the test cases upon the release of the first build by the developers. This follows recording of defects in a defect profile document.

# The defect profile document is transferred to the developers for improvements / eradication of defects found by them. The testing process halts here till next build with improvements is released by the developers.

# The entire testing process involving execution of test cases is repeated on the new build. This process of code improvement, subsequent testing on new builds & finding of defects continues again and again till the product is free from defects.

# The testing process is decided to be stopped after gaining reasonable confidence of product being defect free

Ultimate objective of this phase is to produce a Quality Product.

Phase – 6: Delivery and Maintenance phase: Involves Installing the newly developed application under the client environment.

Personnel Involved: Senior Testing Engineers who are entrusted the task of Deployment Engineers.

Process Involved: 

# Delivery: After the code is appropriately tested, it is approved for release, it is deployed into a production environment. The deployment of application is done with the help of guidelines provided in the application deployment document.

# Maintenance: After the deployment of the application, client may encounter many task-based problems. 

Maintaining and enhancing the software to cope up with newly discovered problems or new requirements can take far more time than the initial development of the software. It may be necessary to add some code, which does not fit the original design to correct an unforeseen problem. It may be that the customer is requesting more functionality, and some code can be added to take care of his requests.