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Introduction
There are various software development approaches defined and designed which are used/employed during development process of software, these approaches are also referred as "Software Development Process Models".
Each process model follows a particular life cycle in order to ensure success in process of software development.
Computer software has become a driving force. It is the engine that drives business decision making. It serves as the basis for modern scientific investigation and engineering problem solving. It is a key factor that differentiates modern products and services. It is embedded in systems of all kinds: Transportation, Medical, Telecommunications, Military, Industrial processes, Entertainment, office products the list is almost endless. Software is virtually inescapable in a modern world.
Software Engineering:-
The application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software is called software engineering.
The term software engineering was popularized by F.L. Bauer during the NATO software Engineering conference in 1968.
It encompasses techniques and procedures, often regulated by a software development process, with the purpose of improving the reliability and maintainability of software systems. The discipline of software engineering includes knowledge, tools and methods for software requirements, software design, software construction, software testing, and software maintenance tasks. Software engineering is related to the disciplines of computer sciences, computer engineering, management, mathematics, quality management, software ergonomics, and systems engineering.
Common problems in software development:-
Poor requirements: If requirements are not clear, incomplete, too general, or not testable, there will be problems.
Unrealistic schedule: if too much of work is crammed in too little time, problems are inevitable.
Inadequate testing: No one will know whether or not the program is any good until the customer complains or system crash.
Lack of communications: If developers do not know what’s needed or customers have erroneous expectations, problems are guaranteed.
Testing objectives:-
Identification of errors: - These are obvious anomalies that show up in the behavior of a program or unit or a component. Such behavior as the following is considered an error:
 Wrong totals
 Misalignments
 Message that say the wrong thing
 The delete button should not delete
Conformance to requirements: - These errors are the results of testing the function in the software against the requirements definition document to ensure that every requirement, functional or non-functional is in the system and that it operates properly. This is also called as operational qualification.
Performance qualification: - These are not errors as such but failures to conform to performance requirements. Technically, they can be part of the second type. How ever performance qualification became a standard way of testing for historical reasons.
Software life cycle Development stages:-
A software development life cycle is the process followed when developing information gathering, all the way through to maintenance and support of the system.
SDLC is also known as information systems development or application development. An SDLC should result in a high quality system that meets or exceeds customer expectations, within time and cost estimates, works effectively and efficiently in the current and planned information technology infrastructure, and is cheap to maintain and cost –effective to enhance. SDLC is a systematic approach to problem solving and is composed of several phases each comprised of multiple steps:
Any software development has to go through the following stages:
o Business Requirements Gathering
o Feasibility Analysis
o Functional Requirements Gathering & Analysis
o Design
o Coding
o Testing
o Release and maintenance
1. Initial:-
In this phase major responsibility are as follows
i. End user interactions.
ii. Requirement collection.
iii. Existing business model study.
iv. Gap analysis.
v. Suggesting solution for the gap.
The role involved in this phase to carry on above responsibilities is business analysis. BA will accomplish all this responsibility as per the guide line provided by the specific quality standards in terms of the process.
Once he collects all the information from the customer he will be documenting in terms of Business Design Document (BDD). This document can also termed as various companies (BD, BRS, BRD, FRS) etc. Every role for his documentation has use a specific template to make sure the perfection of the documentation.
Note: BDD-Business Design Document, BRS - Business Requirement Specification, BRD- Business Requirement Document, FRS- Functional Requirement Specification.]
Template:-
It is defined as predefined format in which the required fields are defined for which the information can be given to prepare a document.
Once the document prepared the same is available as a mail to rest of the team members or through the means of common repository (CR) which is kind of share server. Apart from BA the engagement manager will be exercising his responsibilities in this phase in terms of monitoring factor.
2. Analysis:-
This phase is meant for the following responsibilities.
1) Analyzing the requirements
2) Feasibility study(Technology and system feasibility, Economic feasibility, Legal feasibility, Operational feasibility, Schedule feasibility, Resource feasibility) evaluation or analysis of the potential impact of a proposed project
3) Technology selection
4) Tentative project plan preparation (PM does it in association with a system analyst)
5) System requirement specification analysis
All the above responsibilities efficiently carried on by the system analyst with the help of assigned process.
Having done the analysis the entire information is documented in terms of system requirement specification.
3. Design:-
This phase is meant for designing the project, in other words development of blue print or a plan to constructing a project. Designing activities can be done in the following two ways.
a) High Level Designing (HLD)
b) Low Level Designing (LLD)
High Level Design:-
It is the type of design in which how many modules an entire project can be divided into is determined. (Module is defined as a collection of similar functionalities which together work for a specific service).
Low Level Design:-
It is a type of design in which how many sub modules / units an entire module can be divided is determined.
High level design is done by CA where as low level design is done by TL.
Following the process the design activity will be accomplished effectively and is documented in terms of Technical Design Document (TDD).
1. Overall design description
2. Detailed design description
3. Flow Charts
4. Various design diagrams
Object Diagrams
Class Diagrams
Activity Diagrams
Sequence Diagrams
5. DFD
6. Functional Specification(Pseudo Code it is a key input for developers)