System development life cycle-Naveen vijay

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SDLC SMBS

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THE SYSTEM DEVELOPMENT LIFE CYCLE

What is an information system ?

Hardware, software, data, people, and procedures that

work together to produce quality information

Hardware, software, data, people, and procedures that

work together to produce quality information

System—Set of components that interact to achieve

common goal

System—Set of components that interact to achieve

common goal

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Phases of the SYSTEM DEVELOPMENT CYCLE

Phase 1. Planning

Phase 2. Analysis

Phase 3. Design

Phase 4. Implementation

Phase 5. Support

Review project requests Prioritize project

requestss Identify project

development team

Conduct preliminary investigation Perform detailed analysis activities:

Study current system

Determine user requirements

Recommend solution

Acquire hardware and software, if necessary

Develop details of system

Develop programs, if necessary Install and test new system Train users Convert to new system

Conduct post-implementation system review

Identify errors and enhancements Monitor system performance

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What are some reasons to create or modify an information system?

Competition can lead to change

To improve existing system

Outside group may mandate change

To correct problem in existing system

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PLANNING PHASE

Begins when steering committee receives project request

Steering committeecommittee——

decision-making decision-making body for the body for the

companycompany

Function of committee:

Review and Review and approve project approve project

requestsrequests

Allocate Allocate resourcesresources

Form project Form project development development team for each team for each

approved approved projectproject

Prioritize Prioritize project requestsproject requests

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ANALYSIS PHASE

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SDLC SMBS "ANALYSIS PHASE"

SYSTEMS ANALYSIS

SYSTEM ANALYSIS

Systems analysis is the application of analytical processes to the planning, design and implementation of new and improved information systems to meet the business requirements of customer organizations.


Conduct preliminary Conduct preliminary investigation,investigation,

Cost Estimates Cost Estimates

Alternatives, Alternatives, Existing system Existing system

EvaluationEvaluation



What are the users NEED? What are the users NEED? What must be done to solve?What must be done to solve?

ANALYSIS PHASE

What is the preliminary investigation? Determine exact nature of problem or improvement

and whether it is worth pursuing Findings are presented in feasibility report, also known as a

feasibility study



Some information gathering techniques

Review documentation Observe Questionnaire Interview Research



What is detailed analysis?

Sometimes called logical design

2. Determine user’s wants, needs, and requirements

3. Recommend solution

1. Study how current system works



FACT FINDINGFacts about existing systems can be found out by: Asking questions (Interviews with users). Questionnaires (Completed by users). Observation (Watching how the work is done at

present). Inspection (Looking at existing paperwork, screen

displays, and filing systems).




What is FEASIBILITY?

Measure of how suitable

system development will be to the

company

Operational feasibility

Schedule feasibility

Four feasibility tests:

Technical feasibility

Economic feasibility

(also called cost/benefit feasibility)


FEASIBILITY STUDY The aim of a feasibility study is to see if it is

possible to devise a system that can be implemented and that will work at a reasonable cost.

The study ends when a decision whether or not to proceed with the new system has been made.

The results of the study are usually presented as a feasibility report.



The FEASIBILITY STUDY will normally include: A description of the tasks the system is required to

do. A preliminary design and initial costs for the system. Alternative designs so that the most appropriate can

be chosen. A cost/benefit analysis. Conclusions as to whether or not the design is worth

implementing and which of the alternatives should be chosen.



The ANALYSIS PHASE includes: The drawing of system flow charts and data flow

diagrams. The identification of the proposed system’s objectives. Facts about the system that is going to be replaced. An outline of any constraints or limits (e.g. lack of time,

money, or staff training). An updated cost/benefit analysis. An outline of any further developments of the system.



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QUERIES?

QUESTIONS?


DESIGN PHASE

Acquire hardware and softwareAcquire hardware and software

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How must the problem be solved?How must the problem be solved?

Develop all details of new or modified information system

Develop all details of new or modified information system

Program Construction and TestingProgram Construction and Testing

What is a detailed design?

Includes several activities

Database design

Database design

Input and output design

Input and output design

Program design

Program design

Detailed design specifications for components in proposed solution

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TYPES OF TESTS

Verifies application works with the users

system

Integration test

User acceptance Test

Unit Test

Verifies each individual program

works by itself

Combine each units and verify it

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Convert to new systemConvert to new system

IMPLEMENTATION PHASE Purpose is to construct, or build, new or modified

system and then deliver it to users

Train usersTrain users

Install and test new systemInstall and test new system

Develop programsDevelop programs

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SUPPORT PHASE

Conduct post-implementation system review—meeting to find out if information system is performing according to expectations

EVALUATION

MAINTENANCE

Is the key system is running?

Provides ongoing assistance after system is implemented

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QUERIES OR QUESTIONS?

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Technology

System development life cycle-Naveen vijay