Chapter 7 System Life Cycle System Life Cycle Methodologies Methodologies MANAGEMENT INFORMATION SYSTEMS 8/E Raymond McLeod, Jr. and George Schell Copyright 2001 Prentice-Hall, Inc. 7-1
Jan 14, 2016
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
Steps (cont.)Steps (cont.)
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
Steps (cont.)Steps (cont.)
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
8. Expected impact of the system8.1 Impact on the firm’s organization structure8.2 Impact on the firm’s operations8.3 Impact on the firms resources
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
•Magnetic tapeMagnetic tape•DASDDASD
•Magnetic tapeMagnetic tape•DASDDASD
•Magnetic tapeMagnetic tape•DASDDASD
•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
Magnetic Magnetic tapetape
Magnetic Magnetic tapetape
Magnetic Magnetic tapetape
Magnetic Magnetic tapetape
Magnetic Magnetic tapetape
Magnetic Magnetic tapetape
Magnetic Magnetic tapetape
Magnetic Magnetic tapetape
Magnetic Magnetic tapetape
Magnetic Magnetic tapetape
Magnetic Magnetic tapetape
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
8. Expected impact of the system8.1 Impact on the firm’s organization structure8.2 Impact on the firm’s operations8.3 Impact on the firms resources
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