Chap07

Chapter 7System Life CycleSystem Life Cycle

MethodologiesMethodologies

MANAGEMENT INFORMATION SYSTEMS 8/ERaymond McLeod, Jr. and George Schell

Copyright 2001 Prentice-Hall, Inc.7-1

The Systems Life Cycle The Systems Life Cycle (SLC)(SLC) MethodologyMethodology

– Recommended way of doing somethingRecommended way of doing something An application of the systems approach An application of the systems approach

to the task of developing and using a to the task of developing and using a computer-based systemcomputer-based system

Often called waterfall approachOften called waterfall approach

7-2

Phases in the SDLCPhases in the SDLC

1) Planning1) Planning

2) Analysis2) Analysis

3) Design3) Design

4) Implementation4) Implementation

5) Use 5) Use

7-3

The System Development The System Development Life Cycle (SDLC)Life Cycle (SDLC)

SDLC is the phrase that encompasses the planning, SDLC is the phrase that encompasses the planning, analysis, design, and implementation phases of the system analysis, design, and implementation phases of the system life cyclelife cycle

Who participatesWho participates– IS personnelIS personnel

– UserUser

– Information specialists can consultInformation specialists can consult

TraditionalTraditional

– Information specialists working with users.Information specialists working with users.

– A new strategy: OutsourcingA new strategy: Outsourcing

7-4

Life Cycle ManagementLife Cycle Management

An upward migrationAn upward migration Executive responsibilityExecutive responsibility MIS steering committeeMIS steering committee

– FunctionsFunctions» Set policySet policy

» Control the purse stringsControl the purse strings

» Resolve conflictsResolve conflicts

7-5

Executives

MIS SteeringCommittee

Project leader -Warehouse location model team

Project leaderMRP 11 team

Project leaderISDN system team

Project leader HRIS team

Marketing

Manufacturing

Finance

HumanResources

Project leaderCredit approvalsystem team

Managers of Systems Life Cycles are Arranged in a HierarchyManagers of Systems Life Cycles are Arranged in a Hierarchy

7-6

Main Advantages of Main Advantages of the Steering Committeethe Steering Committee

Total firm supportTotal firm support Projects will be characterized by good Projects will be characterized by good

planning and controlplanning and control Establishes policies, provides fiscal control, Establishes policies, provides fiscal control,

and resolves conflictsand resolves conflicts

Since the steering committee will probably not get involved with the details of the work, a project team is usually appointed.

7-7

Planning PhasePlanning Phase

BenefitsBenefits– Define scope of the projectDefine scope of the project

– Spot potential problemsSpot potential problems

– Arrange tasks in sequenceArrange tasks in sequence

– Provide basis for controlProvide basis for control

7-8

StepsSteps

1. Recognize problem (the trigger)1. Recognize problem (the trigger)

2. Define problem 2. Define problem

3. Set objectives3. Set objectives

4. Identify constraints4. Identify constraints

Recall that objectives, standards, and constraints are problem-solving elements.

7-9

Steps (cont.)Steps (cont.)

5.5. Conduct feasibility study (TENLOS)Conduct feasibility study (TENLOS)– TechnicalTechnical– Economic returnEconomic return– Noneconomic returnNoneconomic return– Legal and ethicalLegal and ethical– OperationalOperational– ScheduleSchedule

7-10


6.6. Prepare study project proposalPrepare study project proposal– Goes to MIS steering committeeGoes to MIS steering committee

7.7. Approve or disapprove (go/no go)Approve or disapprove (go/no go)– Key questions?Key questions?

1.1.Will the system accomplish its goals?Will the system accomplish its goals?

2.2.Is this the best way to go about it?Is this the best way to go about it?

7-11


8.8. Establish a control mechanismEstablish a control mechanism– Think in terms of:Think in terms of:

» 1. What1. What

» 2. Who2. Who

» 3. When (Person-months versus calendar months)3. When (Person-months versus calendar months)

– PERT and CPM network diagramsPERT and CPM network diagrams

7-12

Define theproblem

ConsultConsult

Prepare a system study proposal

Establish a control mechanism

Approve or disapprove the study project

Recognize the problem

Set system objectives

Identify systemconstraints

The Planning PhaseThe Planning PhaseMIS Steering Comm Manager Systems AnalystMIS Steering Comm Manager Systems Analyst

1.1.

2.2.

3.3.

4.4.

5.

6.

7.7.

8.8.

Conduct a feasibility study

7-13

Outline of a System Study ProposalOutline of a System Study Proposal1. Executive summary2. Introduction3. System objectives and constraints4. Possible system alternatives5. The recommended system study project

5.1 Tasks to be performed5.2 Human resource requirements5.3 Schedule of work5.4 Estimated cost

6. Expected impact of the system6.1 Impact on the firm’s organization structure6.2 Impact on the firm’s operations6.3 Impact on the firms resources

7. General development plan (analysis, design, and implementation phase)

8. Summary7-14

A Project ScheduleA Project ScheduleFunctional System:Functional System: MarketingMarketing

Subsystem:Subsystem: ProductProduct

Model:Model: Product DeletionProduct Deletion

SubtaskSubtaskTime Time

EstimateEstimate(Person Months)(Person Months)

ResponsibilityResponsibility

1. Identify 1. Identify deletion criteriadeletion criteria

2. Identify output 2. Identify output information information requirementsrequirements

Systems analystSystems analystProduct managerProduct manager

Systems analystSystems analystNetwork specialistNetwork specialistProduct managerProduct manager

0.750.75

0.250.257-15

Project Schedule (cont.)Project Schedule (cont.)

3. Identify input data Systems analyst 0.503. Identify input data Systems analyst 0.50

requirements DBArequirements DBA

4. Prepare new system Systems analyst 2.004. Prepare new system Systems analyst 2.00

documentation documentation

5. Design network Network specialist 1.50 5. Design network Network specialist 1.50

6. Design database DBA 0.50 6. Design database DBA 0.50

7. Review design Product manager 0.257. Review design Product manager 0.25

Systems analystSystems analyst

8. Prepare program Programmer 1.00 8. Prepare program Programmer 1.00

documentationdocumentation

7-16

Project Schedule (cont.)Project Schedule (cont.)

9. Code program Programmer 1.259. Code program Programmer 1.25

10. Test program Programmer 0.7510. Test program Programmer 0.75

Operations staffOperations staff

11. Approve program Product manager 0.5011. Approve program Product manager 0.50

VP of marketingVP of marketing

12. Prepare database DBA 2.0012. Prepare database DBA 2.00

13. Educate users Systems analyst 0.5013. Educate users Systems analyst 0.50

14. Cutover to model Operations staff 0.7514. Cutover to model Operations staff 0.75

7-17

Analysis PhaseAnalysis Phase

StepsSteps1.1.AnnounceAnnounce

» Reasons for projectReasons for project

» Purpose: inform and counteract fearPurpose: inform and counteract fear

2.2.Organize project team Organize project team » User(s)User(s)

» SpecialistsSpecialists

» Define rolesDefine roles

7-18

Analysis Phase (cont.)Analysis Phase (cont.)

3.3. Define information needsDefine information needs» MethodsMethods

Personal interview (the preferred method)Personal interview (the preferred method) ObservationObservation Record search (includes review of existing Record search (includes review of existing

documentation)documentation) SurveysSurveys

A project directory can be maintained as an encompassing set of documentation to describe the system

7-19

Analysis Phase (cont.)Analysis Phase (cont.)

4.4. Define system performance criteriaDefine system performance criteria

5.5. Prepare design proposalPrepare design proposal

(Compare to system study proposal)(Compare to system study proposal)

6.6. Approve or disapprove the design Approve or disapprove the design projectproject

7-20

Announce the system study

Organize the project team

Define information needs

Define system performance criteria

Preparedesign

proposal

Approve or disapprove the design project

1.

2.

3.

4.

5.

6.

The Analysis PhaseThe Analysis PhaseMIS Steering MIS Steering CommitteeCommittee ManagerManager Systems AnalystSystems Analyst

7-21

Outline of a Design ProposalOutline of a Design Proposal1. Executive summary2. Introduction3. Problem definition4. System objectives and constraints5. Performance criteria6. Possible system alternatives7. The recommended design project

7.1 Tasks to be performed7.2 Human resource requirements7.3 Schedule of work7.4 Estimated cost


9. General development plan (analysis, design, and implementation)10. Summary

7-22

Approve or disapprove the system Approve or disapprove the system implementationimplementation

Prepare the Prepare the detailed detailed design design systemsystem

Identify Identify alternate alternate system system

configurationsconfigurations

Evaluate Evaluate system system

configurationsconfigurations

Select the Select the best best

configurationconfiguration

Prepare the Prepare the implementation implementation

proposalproposal

1.1.

2.2.

3.3.

4.4.

5.5.

6.

MIS Steering CommitteeMIS Steering Committee ManagerManager Systems AnalystSystems Analyst

The Design PhaseThe Design Phase

7-23

Design PhaseDesign Phase

1.1. Prepare detailed designPrepare detailed design– Structured design (top down)Structured design (top down)

» System levelSystem level

» Subsystem levelSubsystem level

– Documentation toolsDocumentation tools

2. Identify alternate system configurations2. Identify alternate system configurations– Refine to a manageable setRefine to a manageable set

7-24

Popular Documentation ToolsPopular Documentation Tools

Data Modeling Entity-relationship diagram

Data dictionaryScreen/printer layout form

Process Modeling System flowchartProgram flowchartData flow diagramStructured English

Object Modeling Object relationship modelClass specification

7-25

Data Flow Diagram of Four Data Processing Data Flow Diagram of Four Data Processing SubsystemsSubsystems

Customers

1.4Accounts

Receivable

1.1OrderEntry

1.3Billing

1.2Inventory

Sales orders

Rejected salesorder notices

Accepted orders

Payments bycustomers

Sta

tem

ents

Invoices

Billed orders

Receivables ledger data

Order logremovals file

Filled items

Inventoryledger data

Received items

Purchasing data

3

3 2

2

7-26

Data Flow Diagram of Order Entry SystemData Flow Diagram of Order Entry SystemSales orderedit rejects

Order log

Sales ordercredit rejects

Customercredit file

Customer

1.1.1Edit

orderdata

1.1.2Compute

creditcheck

1.1.3Log inorders

1.1.4Markfilled

orders

1.2

1.3

Sales orders Edit rejects

Rejectedsales ordernotices

Edited orders

Credit data

Edited and checked orders

Credit rejects

Acceptedorders

Completed orders Date filled

Order data

7-27

Hardware Choices Make Possible Hardware Choices Make Possible Multiple System ConfigurationsMultiple System Configurations

System ElementsSystem Elements AlternativesAlternatives•CRT terminalCRT terminal•Hardcopy terminalHardcopy terminal•OCROCR

Input

Order log

Customer credit file

Rejected orders file

Accepted orders file

Completed orders file

Rejected orders notice

Processing

•Magnetic tapeMagnetic tape•DASDDASD





•PrinterPrinter•CRT terminalCRT terminal•Hardcopy terminalHardcopy terminal•BatchBatch

•OnlineOnline

7-28

Alternatives Selected for Alternatives Selected for Detailed StudyDetailed Study

Alternative Alternative InputInput

Order Order LogLog

Customer Customer Credit FileCredit File

Accepted & Accepted & Rejected Rejected

Orders FileOrders File

Completed Completed Orders FileOrders File

Rejected Rejected Orders Orders NoticeNotice

11..

22..

33..

ScannerScanner

Keyboard Keyboard terminalterminal

Magnetic Magnetic tapetape

Keyboard Keyboard terminalterminal












PrinterPrinter

PrinterPrinter

Hardcopy Hardcopy terminalterminal

7-29

Design Phase (cont.)Design Phase (cont.)

3. Evaluate configurations3. Evaluate configurations

4. Select best configuration4. Select best configuration

5. Prepare implementation proposal5. Prepare implementation proposal

6. Approve or disapprove the system 6. Approve or disapprove the system implementationimplementation

7-30

1. Executive summary2. Introduction3. Problem definition4. System objectives and constraints5. Performance criteria6. System design

6.1 Summary description6.2 Equipment configuration

7. The recommended implementation project7.1 Tasks to be performed7.2 Human resource requirements7.3 Schedule of work7.4 Estimated cost


9. General implementation plan10. Summary

Outline of an Implementation Outline of an Implementation ProposalProposal

7-31

Implementation PhaseImplementation Phase

Acquire and integrate the physical and Acquire and integrate the physical and conceptual resources to produce a conceptual resources to produce a working systemworking system

7-32

Steps for the Implementation Steps for the Implementation PhasePhase

1. Plan implementation

2. Announce

3. Obtain hardware resources

RFP / Written Proposals

4. Obtain software resources

"Make or buy"

5. Prepare database

6. Prepare physical facilities

7. Educate participants and users

8. Prepare cutover proposal

9. Approve or disapprove cutover to new systsem

10. Cutover to new system

7-33

Plan the implementation

Announce the implementation

Control

Cutover the new system

Obtain the hardware resources

Obtain the softwareresources

Prepare the database

Educate the participants and users

Prepare the physical facilities

Control

1.1.

2.2.

33

44

55

66

77

8.

The Implementation PhaseThe Implementation PhaseMIS Steering CommitteeMIS Steering Committee ManagerManager Information SpecialistsInformation Specialists

7-34

Outline of a Request for Outline of a Request for ProposalProposal

1. Letter of transmittal2. System objective and applicable constraints3. System design

3.1 Summary description3.2 Performance criteria3.3 Equipment configuration3.4 Summary system documentation3.5 Estimated transaction volume3.6 Estimated file size

4. Installation schedule

7-35

Outline of Supplier ProposalOutline of Supplier Proposal

1. Letter of transmittal2. Summary of recommendations3. Advantages4. Equipment configuration5. Equipment specifications

5.1 Performance data5.2 Prices

6. Satisfaction and performance criteria7. Delivery schedule

7-36

Cutover ApproachesCutover Approaches

Old System

Old System New System

Immediate cutoverPhased cutover

Parallel cutover

Pilot System

Immediate

Old SystemNew SystemPhased

New system

Old SystemParallel

Time

Pilot

7-37

Use PhaseUse Phase 1.1.UseUse

2.2.Audit (post implementation review)Audit (post implementation review)» By information specialist(s)By information specialist(s)» By internal auditor (a different one from the By internal auditor (a different one from the

project team member)project team member)

3. Maintain the system3. Maintain the system» Correct errorsCorrect errors» Keep currentKeep current» ImproveImprove

4. Prepare reengineering proposal4. Prepare reengineering proposal

5. Approve or disapprove reengineering5. Approve or disapprove reengineering7-38

The Use The Use PhasePhase

ControlUse thesystem

Audit thesystem

Maintain the

system

Preparere-

engineeringproposal

Approve or disapprove thereengineering proposal

MIS Steering Committee Manager Information Specialists

12

3

4

5

7-39

PrototypingPrototyping

Type I -- Becomes operational systemType I -- Becomes operational system

Type II -- Serves as a blueprintType II -- Serves as a blueprint

7-40

Development of a Type I PrototypeDevelopment of a Type I Prototype

1.1.

2.2.

3.3.

4.4.

NN

Identify user needsIdentify user needs

Develop a prototypeDevelop a prototype

Prototype Prototype acceptable?acceptable?

YY

Use the prototypeUse the prototype

7-41

DevelopmeDevelopment of a nt of a Type II Type II

PrototypePrototype

NN

NN

Identify user Identify user needsneeds

Develop a Develop a prototypeprototype

Code the Code the operational systemoperational system

Test the Test the operational systemoperational system

Use the Use the operational systemoperational system

Prototype Prototype acceptable?acceptable?

System System acceptable?acceptable?

YY

YY

7-42

The Attraction of The Attraction of PrototypingPrototyping

Communications between the systems analyst Communications between the systems analyst and user are improved.and user are improved.

The analyst can do a better job of determining The analyst can do a better job of determining the user’s needs.the user’s needs.

The user plays a more active role in system The user plays a more active role in system development.development.

The information specialists and the user spend The information specialists and the user spend less time and effort in developing the system.less time and effort in developing the system.

Implementation is much easier because the Implementation is much easier because the user knows what to expect.user knows what to expect.

7-43

Potential Pitfalls of PrototypingPotential Pitfalls of Prototyping The haste to deliver the prototype may produce The haste to deliver the prototype may produce

shortcuts in problem definition, alternative shortcuts in problem definition, alternative evaluation, and documentation.evaluation, and documentation.

The users may get so exited about the prototype that The users may get so exited about the prototype that they have unrealistic expectations of the operational they have unrealistic expectations of the operational system.system.

Type I prototypes might not be as efficient as systems Type I prototypes might not be as efficient as systems coded in a programming language.coded in a programming language.

The computer-human interface provided by certain The computer-human interface provided by certain prototyping tools may not reflect good design prototyping tools may not reflect good design techniques.techniques.

7-44

Applications That Are Applications That Are Good Prospects for Good Prospects for

PrototypingPrototyping High riskHigh risk Considerable user interactionConsiderable user interaction Large number of usersLarge number of users A need for quick deliveryA need for quick delivery An expected short use phase of the systemAn expected short use phase of the system An innovative systemAn innovative system Unpredictable user behaviorUnpredictable user behavior

7-45

Rapid Application Development Rapid Application Development (RAD)(RAD)

Information engineering (IE)Information engineering (IE) Key ingredientsKey ingredients

– Management should be experimenters or Management should be experimenters or early adaptersearly adapters

– Specialized teamsSpecialized teams– Methodologies (RAD life cycle)Methodologies (RAD life cycle)– Tools (I-CASE, 4GLs)Tools (I-CASE, 4GLs)

RAD and the SLC are applications of the RAD and the SLC are applications of the systems approachsystems approach

Tools are mainly 4th generation languages and Tools are mainly 4th generation languages and CASE toolsCASE tools

7-46

Informationstrategyplanning

(ISP)

Business areaanalysis(BAA)

Rapid application development(RAD)

.

Strategic overview of theinformation needed to runan enterprise as efficientlyas possible

Data model

Design of records used by specificprocedures

Strategic overview of thefunctions and goals ofan enterprise

The process needed tooperate the enterpriseand how they interrelate

Design ofprocedures forspecific applications

Rapid Application Development is an Integral Part of Information Engineering

DataActivities

7-47

Business Process Redesign Business Process Redesign (BPR)(BPR)

Often used to react to systems that can no Often used to react to systems that can no longer function adequately in the current longer function adequately in the current business environment of the firm (legacy business environment of the firm (legacy systems fall into this category)systems fall into this category)

Three techniques for business process Three techniques for business process redesign areredesign are1) reverse engineering1) reverse engineering

2) restructuring2) restructuring

3) reengineering3) reengineering 7-48

Reverse EngineeringReverse EngineeringReverse Engineering Produces Documentation on Successively Reverse Engineering Produces Documentation on Successively

Higher Levels but Leaves the System UnchangedHigher Levels but Leaves the System Unchanged

ReverseReverse

EngineeringEngineering EngineeringEngineering

ReverseReverse

EngineeringEngineering

ReverseReverse

EngineeringEngineering

ReverseReverse

Planning Planning PhasePhase

Analysis Analysis PhasePhase

Design Design PhasePhase

Implementation Implementation PhasePhase

7-49

RestructuringRestructuring

PlanningPhase

Restructuring Restructuring Restructuring Restructuring

AnalysisPhase

DesignPhase

ImplementationPhase

7-50

ReengineeringReengineeringReverseEngineering

ReverseEngineering

ReverseEngineering

ReverseEngineering

ForwardEngineering

ForwardEngineering

ForwardEngineering

ForwardEngineering

Planning Phase

Analysis Phase

DesignPhase

ImplementationPhase

7-51

Selection of BPR Selection of BPR ComponentsComponents

Based upon functional qualityBased upon functional quality– What the system doesWhat the system does

Based upon technical qualityBased upon technical quality– How the system does its jobHow the system does its job

The relationship between these two The relationship between these two characteristics suggest which BPR characteristics suggest which BPR technique would be appropriatetechnique would be appropriate

7-52

FunctionalQuality(What?)

Good

Technical Quality(How?)

Poor

Poor

Good

Selection of BPR Components

Reverse Engineer

Restructure

Do Nothing

ForwardEngineer

Reengineer

7-53

SLC, Prototyping, RAD, SLC, Prototyping, RAD, and BPR in Perspectiveand BPR in Perspective

SLC, prototyping, and RAD are all SLC, prototyping, and RAD are all methodologiesmethodologies– Recommended ways of implementing a Recommended ways of implementing a

computer-based systemcomputer-based system BPR revamps systems that were BPR revamps systems that were

implemented with computer technology that implemented with computer technology that has become obsoletehas become obsolete

7-54

SummarySummary

System Life CycleSystem Life Cycle– PlanningPlanning– AnalysisAnalysis– DesignDesign– ImplementationImplementation– UseUse

Cycle management responsibilityCycle management responsibility Other methodologiesOther methodologies

7-55

Chap07

Business

design project

system constraints

system objectives

system study proposal

study project proposal

project purpose

system performance criteria

design proposal