7 system development

7/27/2019 7 System Development

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System Development & Org. Change

• Information System building is a kind of planned organisational change.

• Four types of structural organisational change – Automation – Rationalisation – Reengineering and – Paradigm shifts

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PARADIGMSHIFTS

REENGINEERING

RATIONALISATION

AUTOMATION

HIGH

HIGHLOW

LOW

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Business Process Reengineering

• Business Process Reengineering (BPR): – Business process are analyzed, simplified and

redesigned. – Rethink and streamline business process

• BPR is basically a fundamental of redesigningbusiness processes so as to gain economy inperforming the various business process. InBPR, unnecessary processes are eliminated andchanging the process which are central.

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BPR : BUSINESS PROCESS REENGINEERING

• BPR can be redefined as radical scrutiny,questioning, redefining, and redesigning of

business processes with the aim of eliminatingall activities not central to business goals.

• The concept emerged from Japan, spread toUSA and from USA, throughout the world.

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Process of BPR• Developing business vision and process

objectives.• Identifying the process to be redesigned•

Measuring the performance of ExistingProcesses.• Identifying the opportunity for applying

Information Technology• Building prototype of new process• Structural Change• Organizational Cultural Change

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• Paradigm shift: – Change its business model – Involves rethinking the nature of business, defining a

new business model and often changing the verynature of business

• Ex. Music Industry, Photography, virtual banking etc.

• BPR & Paradigm shift often fails because of

extensive organisational change but still many organisations go for this because of high rewards,changing business environment…

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SYSTEM DEVELOPMENT APPROACHES

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Systems Development• The activities that go into producing an

information system solution to an organizationalproblem or opportunity are called systemsdevelopment .

• The activities consists of: – Systems Analysis – System Design – Programming – Testing – Conversion –

Production & Maintenance 10



Systems Development Process – 6 core activities

SYSTEMSANALYSIS

SYSTEMDESIGN

PROGRAM-MING TESTING CONVERS-

ION

PRODUCT-ION &

MAINTE-NANCE

USUALLY IN SEQUENTIAL ORDER BUT SOME CAN BE REPEATEDOR DONE SIMULTANEOUSLY 11



Systems Analysis

• Systems Analysis is the analysis of a problemthat an organisation will try to solve with aninformation system.

• It consists of: – Defining the problem – Identifying its causes – Specifying the solution – Identifying the information requirements

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Systems Analysis

- The preliminary investigation is a way of handlinguser's request to change, improve or enhance anexisting system.

- The objective is to determine whether the requestis valid and feasible before any recommendation ismade to do nothing, improve or modify theexisting system.

- System investigation includes following two sub-phases:(1) Problem Definition

(2) Feasibility study 13



Systems Analysis

Problem Definition- The first responsibility of the system analyst is toprepare a written statement of the objectives andscope of the problem- Proper understanding and definition of theproblem is essential to discover the cause of theproblem and to plan a directed investigation byasking questions like

– What is being done? Why? – Is there an underlying reason different from the one

the user identified?

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Systems Analysis

Problem Definition- Some examples of problem definition(1) the existing system has a poor response time,i.e. It is slow(2) it is unable to handle the workload(3) the existing system is not economical

(4) the problem of accuracy and reliability(5) the requisite information is not produced by theexisting system(6) the problem of security

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Systems Analysis

Feasibility Study- this study is undertaken to know the likelihood of thethe system being useful to the organisation- the aim of the study is to assess alternative system andto propose the most feasible and desirable system fordevelopment- the feasibility of a proposed system can be assessed interms of four major categories:

(1) Organisational feasibility(2) Economic feasibility(3) Technical feasibility(4) Operational feasibility

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Systems Analysis

Methods of preliminary investigation- Reviewing organisational documents- Conducting interviews

The following format is suggestive:1. Project title2. Problem statement3. Project objectives4. preliminary ideas - possible solutions5. Project scope - overall cost estimate6. feasibility study

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Systems Analysis•

Detailed study of the various operations of abusiness

• The objective is to determine what must be done

to solve the problem• System analyst most challenging task is to

establish the information needs of the

organisation and its end users-Who needs the information, where, when andhow?

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System Design• System analysis describes WHAT a system should

do to meet the information needs of users.System design specifies HOW the system willaccomplish this objective.

•

It’s a blueprint of the system, consists of all thespecifications that give the system its form andstructure.

• System design targets following three activities :1. user interface2. data design3. process design

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Completing the System DevelopmentProcess

• Now, the remaining steps: – to translate the specifications into fully operational

information system.• It includes

– Programming – Testing – Conversion – Production and Maintenance

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Testing•

Exhaustive and thorough testing is done toascertain whether the system produces rightresults.

• The system should be tested with some testdata to ensure its accuracy and reliability

• Test plan are made and following tests aredone:

–

Unit testing: Testing each program – System testing: Testing as a whole system – Acceptance testing: Testing by users and reviewed

by management.22



Conversion• Conversion is the process of changing from the old

system to the new system.• Four main conversion strategies:

– Parallel strategy: Both old and new systems run parallel forsome time.

– Direct Cutover: Replaces old system entirely with a newsystem on an appointed day.

– Pilot study: Introduces new system to only a limited area of the organisation.

– Phased approach: Introduces new system in stages• Detailed documentation (for both technical & user

point of view) at each step is necessary for futurereference and review.

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Production & MaintenanceProduction• After the new system is installed and conversion is

complete, the system is in production stage.• Outputs are reviewed by both technical persons and

users.• Post-implementation audit is also done.

Maintenance• Involves monitoring, evaluating and modifying the system

to make desirable and necessary improvements.• It also includes enhancements, modifications or change

from the original specifications.24



ALTERNATIVE SYSTEMS-BUILDINGAPPROACHES

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ALTERNATIVE SYSTEMS-BUILDINGAPPROACHES

• Systems differ in Size , Technological complexity ,in terms of Organizational problems they meantto solve .

• A number of systems-building approaches: – The traditional systems life cycle (Water-fall

approach) –

Prototyping – Application software packages – End-user development and – Outsourcing

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Traditional Systems Life Cycle

• Oldest method for building IS.• It is a phased approach, dividing systems

development into formal stages.• Emphasizes formal specifications and

paperwork generating good documantations.• Still used for building large complex systems,

rigorous & formal requirements, predefinedrequirements etc.

• But it is costly, time consuming and inflexible27



Traditional Systems Life Cycle

• Can go back and forth among stages in life-cycle but predominantely a “ waterfallapproach ”.

• One stage is completed before next stagestarts.

• Not suitable for less structure and moreindividualized systems.

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WATERFALL MODELSYSTEM ANALYSIS

SYSTEM DESIGN

PROGRAMMING

TESTING

CONVERSION

PRODUCTION &MAINTENANCE

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PROTOTYPING•

Building an experimental system rapidly andinexpensively for end users to evaluate.• The prototype is a working version of an

information system or part of the system, as apreliminary model.

• Once designed is finalised, the prototype isconverted into a final production system.

• It is an iterative process of systems development,steps can be repeated over and over again

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Steps in Prototyping

• Step 1: Identify the user’s basic requirements

•

Step 2: Develop an initial prototype

• Step 3: Use the prototype.

• Step 4: Revise and enhance the prototype

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Identify basicrequirements

Develop aworking

prototype

Use theprototype

Revise & enhancethe prototype

Operationalprototype

Usersatisfied

STEP 1

STEP 2

STEP 3

STEP 4

NOYES

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Advantages and disadvantages

• Most useful when some uncertainty aboutrequirements

• Encourages intense users involvement.• More likely to fulfill users requirements• But may miss out some essential steps in systems

development.• Less structured and documentation .• May not accommodate large quantities data.

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End-User Development

• A series of fourth-generation languages makesit possible to develop systems by users withlittle or no formal assistance from technicalspecialists.

• 4 th – Generation languages are software toolsthat enable end-users to create reports or

develop software applications with minimal orno technical assistance.

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F th G ti L



Fourth-Generation Languages• Less procedural than conventional languages

4 th Gen Tool Description Example

PC Software tools General purpose application softwarepackages for PCs

Microsoft Access, Word

Query Language For retrieving data stored in databases orfiles

SQL

Report Generator Extract data from files/database to createcustomise reports Crystal Reports

Graphics language For display data in graphic format SAS Graph, Systat

Applicationgenerator

Contain programme modules thatgenerate entire applications, webpage etc.

FOCUSMicrosoft FrontPage

Application softwarepackage

Software programs sold or leased bycommercial vendors, eliminating the needfor custom-written, in-house software

Oracle Peoplesoft HCM,mySAP ERP

Very high-levelprogramming lang.

Generate program code with fewerinstructions than conventional language

APL, Normad2

Orientedtoward

end-use r

Orientedtoward IS

professional35



Application Software Packages &Outsourcing

• Today, most systems are not developed in-housebut purchased from external sources.

• Firms can rent the software from serviceprovider

• Purchase a software from vendors• Custom application developed by an outside

outsourcing firm .• Many packages like payroll, inventory control,

accounts receivable etc.36



RAD – Rapid Application Development

• Organisation need to be able to add, changeand delete their technology capabilities veryrapidly to respond to new opportunities –

because of digitalised and volatile businessenvironment.• Object-oriented software tools, reusable

software, prototyping, and fourth-generationlanguage tools are helping in this.

• The process to create workable systems in avery short period of time is described as RAD

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