System development life cycle-Naveen vijay

THE SYSTEM DEVELOPMENT LIFE CYCLE
What is an information system ?
Hardware, software, data,
Hardware, software, data,
people, and procedures that
people, and procedures that
work together to produce
work together to produce
quality information
quality information

System—Set of components
System—Set of components
that interact to achieve
that interact to achieve
common goal
common goal

SDLC SMBS

Phases of the SYSTEM DEVELOPMENT CYCLE
Phase 2. Analysis


Phase 1. Planning





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

Phase 5. Support





Conduct post-implementation
system review
Identify errors and enhancements
Monitor system performance

Phase 3. Design




Phase 4. Implementation





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

SDLC SMBS

Acquire hardware
and software, if
necessary
Develop details of
system


SDLC SMBS

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

To correct problem
in existing system

To improve
existing system

Outside group may
mandate change

Competition can
lead to change

SDLC SMBS

PLANNING PHASE
Begins when steering committee receives project request
Steering
committee—
decision-making
body for the
company

Function of committee:
Review and
approve project
requests

Prioritize
project requests

Allocate
resources

SDLC SMBS

Form project
development
team for each
approved
project


ANALYSIS PHASE

SDLC SMBS

SYSTEMS ANALYSIS

SDLC SMBS "ANALYSIS PHASE"

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.


ANALYSIS PHASE

Conduct preliminary
investigation,
Cost Estimates

What are the users NEED?
What are the users NEED?

Alternatives,
Existing system
Evaluation

What must be done to solve?
What must be done to solve?


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?
1. Study how current system
works
2. Determine user’s wants, needs,
and requirements

3. Recommend solution

Sometimes called logical design


FACT FINDING
Facts 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

Four feasibility
tests:
Schedule
feasibility
Economic
feasibility
(also called
cost/benefit
feasibility)

Technical
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.



QUERIES?
QUESTIONS?

SDLC SMBS

DESIGN PHASE
Acquire hardware and software
Acquire hardware and software
Develop all details of new or
Develop all details of new or
modified information system
modified information system
How must the problem be solved?
How must the problem be solved?
Program Construction and Testing
Program Construction and Testing

SDLC SMBS

What is a detailed design?
Detailed design specifications for components in proposed solution

Includes several activities
Database
Database
design
design

Input and
Input and
output design
output design

Program
Program
design
design

SDLC SMBS

TYPES OF TESTS
Unit Test

Integration test

Verifies each
individual program
works by itself

Combine each units
and verify it

User acceptance
Test
Verifies application
works with the users
system
SDLC SMBS

IMPLEMENTATION PHASE


Purpose is to construct, or build, new or modified
system and then deliver it to users
Convert to new system
Train users

Install and test new system

Develop programs
SDLC SMBS

SUPPORT PHASE


Provides ongoing assistance after system is implemented
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?

SDLC SMBS


QUERIES OR QUESTIONS?

SDLC SMBS

System development life cycle-Naveen vijay

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