developing information system solution2

8/11/2019 Developing Information System Solution2

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Developing information system solution

system development life cycle

1. Investigation

2. Analysis

3. Design4. Coding

5. Testing

6. Implementation7. Maintenance


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System Investigation

Product:Feasibility study

System AnalysisProduct:Functional Requirements

System Maintenance

Product:Improved System

System ImplementationProduct:Operational System

System DesignProduct:System Specification


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System development life cycle

Understand the

Business Problem or

opportunity

Develop anInformation System

Solution

Implement the

Information System

solution

Determine whether a business problem or

opportunity exists

Conduct a feasibility study to determine whether a

new or improved information system is a feasible

solution

Develop a project management approval

Analyze the information needs of end users,the

organizational environment and any systempresently used

Develop the functional requirements of a system

that can meet the needs of end users

Develop specifications for the

hardware,software,people,network, and data

resources, and the information products that will

satisfy the functional requirements of the Proposed

system

Acquire(or develop)hardware and software.

Test the system and train people to operate and

use it.

Convert to the new system.

Use a post implementation review process to

monitor, evaluate,and modify the system as needed


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SYSTEM INVESTIGATION

Determine whether a business problem or

opportunity exists

Conduct a feasibility study to determine

whether a new or improved information

system is a feasible solution

Develop a project management approval


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SYSTEM ANALYSIS

Analyze the information needs of end

users,the organizational environment

and any system presently usedDevelop the functional requirements

of a system that can meet the needs

of end users


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SYSTEM DESIGN

Develop specifications for the

hardware,software,people,networ

k, and data resources, and theinformation products that will

satisfy the functional

requirements of the Proposed

system


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System Implementation

Acquire(or develop)hardware and

software.

Test the system and train peopleto operate and use it.

Convert to the new system.


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SYSTEM MAINTENANCE

Use a post implementation

review process to monitor,

evaluate,and modify the

system as needed


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Feasibility Study

A feasibility study is a preliminary studywhich investigates the information needsof prospective users and determines the

resource requirements,costs,benefits andfeasibility of a proposed system.

The goals of feasibility studies is toevaluate alternative systems and topropose the most feasible and desirablesystems for development


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Way to gather information for

system development Interviews with employees,customers,and

managers

Questionnaires to appropriate users in the

organization Personal observation ,videotaping,or

involvement in end user work activities.

Examination ofdocuments,reports,proceduresmannuals,and other documentation


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Types of Feasibility study

Organizational Feasibility

Technical Feasibility Economic Feasibilty

Operational Feasibility


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Organizational Feasibility

How well the proposed

system supports thestrategic objectives of

the organisation


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Technical Feasibility

To study the capability,reliability,and

availability of of hardware,software,and

network


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Economic Feasibility

Costs Savings

Increased revenue

Decreased investment Increased profits


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Operational feasibility

End user Acceptance

Management support

Customer,supplier, and governmentrequirements


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Cost/Benefit Analysis

Feasibility studies typically involves

cost/benefit analysis

Tangible cost & intangible cost

Tangible benefits & Intangible Benefits


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Tangible cost

The costs and benefits which could be

quantified is called tangible.

Examples are

Cost of H/W, S/W, salaries and other

expenses that can be quantified.


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Intangible Costs

The events/transaction etc which can not

be quantified .

Examples

Customer goodwill

Employee morale

Attitude


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Tangible Benefits and Intangible

Benefits

Tangible benefits are favorable results,such as the decreased in payroll costscaused by a reduction in Personnel or a

decrease in inventory carrying costscaused by a reduction in inventory.

Intangible benefits arte harder toestimate.Such benefits as better customerservice or faster and more accurateinformation for management fall into thiscategory


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Examples of Tangible/ Intangible Benefits

Tangible benefits

Increase in sales orprofits

Decrease ininformation

processing costs Decrease in

operating cost

Decrease in

required investment

Increasedoperational abilityand efficiency

Examples

Development ofcomputer_based products

and services.

Elimination of unnecessary

procedures and documents

Reduction in inventorycarrying costs.

Decrease in inventory

investment required

Improvement in production

ability and efficiency forexample,less

spoilage,waste,and idle

time.


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Intangible Benefits New or improved

information availability

Improved abilities in

computation and

analysis

Improved customer

service

Improved management

decision making

Improved competitive

position

Improved business and

community image

Example

More timely and accurateinformation and new types of

information

Analytical modeling

More timely service

response

Elimination of burdensome

boring job tasks

Better information and

decision analysis

Systems which lock in

customers and suppliers

Progressive image as

perceived by

customers,suppliers andinvestors


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System Analysis

It is an in-depth study of end user informationneeds that produces functional requirementsthat are used as the basis for the design of anew information system

It is a detailed study of:The information needs of the organization and

end users

The activities,resources,and procedures of any

present information systemsThe information system capabilities required to

meet your information needs,and those ofother end users.


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Activities associated in System

Analysis Organizational Analysis

Analysis of the Present System

Functional Requirements Analysis


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Organizational Analysis

It is the first step in system analysis.

Before developing the new system the

developer have to know about the

organization like its management

structure,its people,its business

activities,the environmental systems and

its current information systems.


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Analysis of the present system

Before designing a new system,it is important to

study the existing system which has to be

replace

It is needed to analyze how this system useshardware,software,network,and other resources

to convert data resources,such as transactions

data,into information products,like reports and

displays.

After that the developer can find out the

input,processing,output,storage and control for

the proposed system.


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Functional Requirements

Analysis Functional requirements specify

information system capabilities required tomeet the information needs of users.

The key areas where the functionalrequirements should be developed are

User interface requirements

Processing requirementsStorage requirements

Control requirements

ypes o unc ona


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ypes o unc onaRequirements

User interfacerequirements:Theinput /output needs of

end users that mustbe supported byinformationsystem,includingsources,formats,content,volume,andfrequency of eachtype of input andoutput

Processing

requirements:Activities required to convert

input to output.Includes

calculations,decision

rules,and other

processing

operations,and

capacity,throughput,turnaround time,and response

time needed for

processing activities.


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Types of Functional

Requirements Storage

Requirements

Organization,content

size of databases ,types and frequency

of updating and

inquires, and the

length and rationalefor record retention.

Control

requirements

Accuracy,validity,

safety,security,andadaptability

requirements for

system

input,processing,output,and

storage functions.


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System Design

This phase starts after the system analysis

phase is over

In other word the output of the system analysis

phase,is the input for the design phase Data requirements are worked out on the basis

of user requirement estimates.

The identification of data requirements includesidentifying data sources,the nature and type of

data that are available and data gaps if any.


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Objectives of Design

1. Practicality

user-friendly2. Flexibility the system must be responsive

3. Efficiency

* Through put

* Response Time

* Run Time

4. Security-This aspect relates to H/W

reliability,physical security of data and thedetection and prevention of fraud and abuse

of data.


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Stages in system design

It consists of three activities:

1. User Interface Keep it simple

Keep it clean

Organize logically

2. Data Design

3. Process Design


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Principle of System Design

Problem Partitioning

Abstraction

Top-Down Design Bottom Up Design

Modular

Coupling Cohesion


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Constraints on MIS

Internal Constraint :The constraints that are due tothe internal environment of the organization are known as internal

constraints. The major internal constraints on System design are

Support of top mgmt in designing the system;

Structure of the organization and position of managers;

Company polices;

Availability of persons skilled in system and computers

Availability of budgets

Limitation of development time H/w and S/W standards that must be followed.


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External Constraint

The constraints that are due to the

external environment of the organization

are known as external constraints. The

major external constraints are

Needs and satisfaction of the customers;

Government policies;

Restrictions imposed by unions.


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Design Methodology

The scope of the system design is guided by the frame work for the

new system developed during analysis. More clearly defined logical

methods for developing system that meets user requirements has

led to new techniques and methodologies that fundamentally

attempt to do the following:

Improve productivity of analysts and programmers

Improve documentation and subsequent maintenance and enhancements

Cut down drastically on cost overruns and delays

Improve communication among the user, analyst, designer, and programmer.

Standardize the approach of analysis and design

Simplify design by segmentation.


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Structured Design The structured design divides the system into different

modules that are arranged in a hierarchy and organizedin top-down manner. The main objective of structured

design is to reduce the coupling and enhance the

cohesion between different modules.

In the structured design methodology, the system isdesigned through the following steps:

Identification of inputs and outputs from SRS

Description of functional aspects of the system

Representation of system in DFD Formation of Data Dictionary

Documentation of structured design by structure charts.


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Problems in System Design

Problem of scale

Problem of quality

Problem of productivity Problem of Cost

Problem of scheduling

Problem of consistency


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Coding

In this phase, the modules designed in the s/w

design phase are implemented using a

programming language.

The purpose of this phase is to implement the

modules in an optimized manner. It should be simple to read and understand.

An optimized code reduces the testing and

maintenance effort.

The output of this phase is to satisfies the

information requirements.


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Testing

Unit testing: It involves testing of differentcomponents of the information system toensure whether or not the components are

functioning correctly Module testing: To ensure whether or not

the modules are functioning properly.

Subsystem Testing System Testing

Acceptance testing


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Implementation

Implementation

Activites

AcquisitionOf H/W

S/W

And

Services

Software

Development

Or modification

End User

Training

System

Documentation

ConversionParallel

Pilot

Phased


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Objectives of a training programme

To enhance communication among the

members of the development team

To provide knowledge about the new

system

To increase user awareness

To obtain support for the new system from

the top management


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Conversion

Direct changeover

Parallel changeover

Modular changeover Phased wise changeover


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Maintenance

The processes of monitoring, evaluating,

and modifying the existing information

systems to make the required or desirable

improvements is known as systemmaintenance.

It is an on going activity. It covers a variety

of activities including removal programs,design errors, updating documentation,

new improved programs implementation

etc.


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Types of Maintenance

Corrective Maintenance

Adaptive MaintenancePerfective Maintenance


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Evaluation

The utilities that are used to evaluate the

system

Possession utility

Form utility

Place utility

Time utility Goal utility

developing information system solution2

Documents