(SDLC)

System Development Life

Cycle

Amna Razzaq 06Aqsa Ijaz 30Rubab Fatimi 02

Rehab Khan 35Anjuman Chaudhry 45

GROUP 6

“The systems development life cycle (SDLC), also referred to as the application development life-cycle, is a term used in systems engineering, information system and software engineering to describe a process for planning, creating, testing, and deploying an information system.” The systems development life-cycle concept

applies to a range of hardware and software configurations, as a system can be composed of hardware only, software only, or a combination of both.

Definition

An SDLC has three primary business

objectives:

Ensure the delivery of high quality systems;

Provide strong management controls;

Maximize productivity.

Objectives of the SDLC

The systems development life cycle, according

to Elliott & Strachan & Radford (2004),

"originated in the 1960s, to develop large scale

functional business systems in an age of large

scale business conglomerates. Information

systems activities revolved around heavy data

processing and number crunching routines".

History

Model of System Development Life Cycle

The product life

cycle describes the

process for building

information systems in a

very deliberate,

structured and

methodical way,

reiterating each stage of

the product's life.

Phases of System Development Life Cycle

The System Development is the interactive process which consists of the following phases: System Study Feasibility Study Detailed System Study System Analysis System Design Coding Testing Implementation Maintenance

Preliminary system study is the first stage of system

development life cycle. This is a brief investigation

of the system under consideration and gives a clear

picture of what actually the physical system is?

In practice, the initial system study involves the

preparation of a System proposal which lists the

Problem Definition, Objectives of the Study, Terms

of reference for Study, Constraints, Expected

benefits of the new system, etc.

Preliminary System Study

In case the system proposal is acceptable to the management, the next phase is to examine the feasibility of the system.

The feasibility study is basically the test of the proposed system in the light of its workability, meeting user’s requirements, effective use of resources and of course, the cost effectiveness.

These are categorized as: Technical Operational Economic Schedule Social feasibility

Feasibility Study

The detailed investigation of the system is carried out in

accordance with the objectives of the proposed system.

This involves detailed study of various operations

performed by a system and their relationships within and

outside the system.

During this process, data are collected on the available

files, decision points and transactions handled by the

present system. Interviews, on-site observation and

questionnaire are the tools used for detailed system study.

Detailed System Study

Systems analysis is a process of collecting factual

data, understand the processes involved,

identifying problems and recommending feasible

suggestions for improving the system

functioning.

This involves studying the business processes,

gathering operational data, understand the

information flow, finding out bottlenecks and

evolving solutions for overcoming the weaknesses

of the system so as to achieve the organizational

goals.

System Analysis

The most crucial phase in the development of a

system.

 In the design phase the SDLC process continues

to move from the what questions of the analysis

phase to the how .

 The logical design produced during the

analysis is turned into a physical design.

Physical design: a detailed description of what

is needed to solve original problem.

System Design

Data structure, control process, equipment source, workload and limitation of the system, Interface, documentation, training, procedures of using the system, taking backups and staffing requirement are decided at this stage.

There are several tools and techniques used for describing the system design of the system. These tools and techniques are: Flowchart Data flow diagram (DFD) Data dictionary Structured English Decision table Decision tree

System Design

The system design needs to be implemented to make it a workable system. his demands the coding of design into computer language, i.e., programming language. This is also called the programming phase in which the programmer converts the program specifications into computer instructions, which we refer to as programs.

It is an important stage where the defined procedures are transformed into control specifications by the help of a computer language.

Programming tools like compilers, interpreters and language like c, c++, and java etc., are used for coding.

Systems Coding

After codifying the whole programs of the system, a test plan should be developed and run on a given set of test data. The output of the test run should match the expected results.Using the test data following test run are carried out: Program test System test Program test : When the programs have been coded

and compiled and brought to working conditions, they must be individually tested with the prepared test data.

System Test : After carrying out the program test for each of the programs of the system and errors removed, then system test is done.

Systems Testing

After having the user acceptance of the new system developed, the implementation phase begins. Implementation is the stage of a project during which theory is turned into practice. The major steps involved in this phase are:

Acquisition and Installation of Hardware and Software

ConversionUser TrainingDocumentation

System Implementation

Maintenance is necessary to eliminate errors in the system during its working life and to tune the system to any variations in its working environments. It must meet the scope of any future enhancement, future functionality and any other added functional features to cope up with the latest future needs. It has been seen that there are always some errors found in the systems that must be noted and corrected. It also means the review of the system from time to time.

The review of the system is done for: Knowing the full capabilities of the system Knowing the required changes or the additional

requirements Studying the performance.

System Maintenance

Waterfall ModelSpiral ModelRapid Application Development (RAD) ModelV-shap ModelIncremental ModelAgile Model

SDLC Models

Waterfall Model Of The System Development Life Cycle

In the traditional

“waterfall” model of

system

development, each

phase must be

completed before a

subsequent phase

can commence.

Strengths Control.

Monitor large projects.

Detailed steps.

Evaluate costs and completion targets.

Documentation.

Well defined user input.

Ease of maintenance.

Development and design standards.

Tolerates changes in MIS staffing.

Increased development time.

Increased development cost.

Systems must be defined up front.

Rigidity.

Hard to estimate costs, project overruns.

User input is sometimes limited.

Weakness

http://en.wikipedia.org/wiki/Systems_development_life_cycle

http://www.merttol.com/articles/web/web-site-development-life-cycle.html

http://oer.nios.ac.in/wiki/index.php/Phases_of_System_Development_Life_Cycle

References