Chapter 7
System Life Cycle
System Life Cycle
Methodologies
Methodologies
MANAGEMENT INFORMATION SYSTEMS 8/E Raymond McLeod, Jr. and George Schell
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 system
computer-based system
Often called waterfall approachOften called waterfall approach
Phases in the SDLC
Phases in the SDLC
1) Planning
1) Planning
2) Analysis
2) Analysis
3) Design
3) Design
4) Implementation
4) Implementation
5) Use
5) Use
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 cycle life 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
Life Cycle Management
Life 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
Executives MIS Steering
Committee
Project leader -Warehouse location model team
Project leader MRP 11 team
Project leader ISDN
system team
Project leader
HRIS team
Marketing
Manufacturing
Finance
Human Resources
Project leader Credit approval system team
Managers of Systems Life Cycles are Arranged in a Hierarchy
Managers of Systems Life Cycles are Arranged in a Hierarchy
Main Advantages of
Main Advantages of
the Steering Committee
the Steering Committee
Total firm supportTotal firm support
Projects will be characterized by good Projects will be characterized by good
planning and control
planning and control
Establishes policies, provides fiscal control, Establishes policies, provides fiscal control,
and resolves conflicts
and resolves conflicts
Since the steering committee will probably not get involved with the details of the work, a project team is usually appointed.
Planning Phase
Planning 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
Steps
Steps
1. Recognize problem (the trigger)
1. Recognize problem (the trigger)
2. Define problem
2. Define problem
3. Set objectives
3. Set objectives
4. Identify constraints
4. Identify constraints
Recall that objectives, standards, and constraints are problem-solving elements.
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
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?
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
Define the problem
Consult Consult
Prepare a system study proposal
Establish a control mechanism Approve or disapprove the study project
Recognize the problem Set system objectives Identify system constraints
The Planning Phase
The Planning Phase
MIS Steering Comm Manager Systems Analyst
MIS Steering Comm Manager Systems Analyst
Outline of a System Study Proposal
Outline of a System Study Proposal
1. Executive summary 2. Introduction
3. System objectives and constraints 4. Possible system alternatives
5. The recommended system study project 5.1 Tasks to be performed
5.2 Human resource requirements 5.3 Schedule of work
5.4 Estimated cost
6. Expected impact of the system
6.1 Impact on the firm’s organization structure 6.2 Impact on the firm’s operations
6.3 Impact on the firms resources
7. General development plan (analysis, design, and implementation phase)
A Project Schedule
A Project Schedule
Functional System:
Functional System: MarketingMarketing Subsystem:
Subsystem: ProductProduct Model:
Model: Product DeletionProduct Deletion
Subtask
Subtask EstimateEstimateTime Time
(Person Months) (Person Months) Responsibility Responsibility 1. Identify 1. Identify deletion criteria deletion criteria 2. Identify output 2. Identify output
Project Schedule (cont.)
Project Schedule (cont.)
3. Identify input data Systems analyst 0.50
3. Identify input data Systems analyst 0.50
requirements DBArequirements DBA
4. Prepare new system Systems analyst 2.00
4. 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 0.25
7. Review design Product manager 0.25
Systems analystSystems analyst
8. Prepare program Programmer 1.00
8. Prepare program Programmer 1.00
documentationdocumentation
Project Schedule (cont.)
Project Schedule (cont.)
9. Code program Programmer 1.25
9. Code program Programmer 1.25
10. Test program Programmer 0.75
10. Test program Programmer 0.75
Operations staffOperations staff
11. Approve program Product manager 0.50
11. Approve program Product manager 0.50
VP of marketingVP of marketing
12. Prepare database DBA 2.00
12. Prepare database DBA 2.00
13. Educate users Systems analyst 0.50
13. Educate users Systems analyst 0.50
14. Cutover to model Operations staff 0.75
14. Cutover to model Operations staff 0.75
Analysis Phase
Analysis Phase
StepsSteps
1.
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
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
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
project
project
Announce the system study
Organize the project team
Define information needs
Define system performance criteria
Prepare design proposal
Approve or disapprove the design project
1.
2.
3.
4.
5.
6.
The Analysis Phase
The Analysis Phase
MIS Steering MIS Steering
Committee
Committee ManagerManager Systems AnalystSystems Analyst
Outline of a Design Proposal
Outline of a Design Proposal
1. Executive summary 2. Introduction
3. Problem definition
4. System objectives and constraints 5. Performance criteria
6. Possible system alternatives
7. The recommended design project 7.1 Tasks to be performed
7.2 Human resource requirements 7.3 Schedule of work
7.4 Estimated cost
8. Expected impact of the system
8.1 Impact on the firm’s organization structure 8.2 Impact on the firm’s operations
8.3 Impact on the firms resources
9. General development plan (analysis, design, and implementation) 10. Summary
Approve or disapprove the system Approve or disapprove the system
implementation implementation Prepare the Prepare the detailed detailed design design system system Identify Identify alternate alternate system system configurations configurations Evaluate Evaluate system system configurations configurations Select the Select the best best configuration configuration Prepare the Prepare the implementation implementation proposal proposal 1. 1. 2. 2. 3. 3. 4. 4. 5. 5. 6.
MIS Steering Committee
MIS Steering Committee ManagerManager Systems AnalystSystems Analyst
The Design Phase
The Design Phase
Design Phase
Design 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 configurations
2. Identify alternate system configurations
– Refine to a manageable setRefine to a manageable set
Popular Documentation Tools
Popular Documentation Tools
Data Modeling Entity-relationship diagram
Data dictionary
Screen/printer layout form
Process Modeling System flowchart
Program flowchart Data flow diagram Structured English
Object Modeling Object relationship model
Class specification
Data Flow Diagram of Four Data Processing
Data Flow Diagram of Four Data Processing
Subsystems Subsystems Customers 1.4 Accounts Receivable 1.1 Order Entry 1.3 Billing 1.2 Inventory Sales orders Rejected sales order notices Accepted orders Payments by customers S ta te m en ts Invoices Billed orders
Data Flow Diagram of Order Entry System
Data Flow Diagram of Order Entry System
Sales order edit rejects Order log Sales order credit rejects Customer credit file Customer 1.1.1 Edit order data 1.1.2 Compute credit check 1.1.3 Log in orders 1.1.4 Mark filled orders 1.2 1.3
Sales orders Edit rejects
Rejected sales order notices
Edited orders
Credit data Edited and checked orders
Credit rejects Accepted
orders
Completed orders Date filled Order data
Hardware Choices Make Possible
Hardware Choices Make Possible
Multiple System Configurations
Multiple System Configurations
System Elements
System 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
Alternatives Selected for
Alternatives Selected for
Design Phase (cont.)
Design Phase (cont.)
3. Evaluate configurations
3. Evaluate configurations
4. Select best configuration
4. Select best configuration
5. Prepare implementation proposal
5. Prepare implementation proposal
6. Approve or disapprove the system
6. Approve or disapprove the system
implementation
implementation
1. Executive summary 2. Introduction
3. Problem definition
4. System objectives and constraints 5. Performance criteria
6. System design
6.1 Summary description 6.2 Equipment configuration
7. The recommended implementation project 7.1 Tasks to be performed
7.2 Human resource requirements 7.3 Schedule of work
7.4 Estimated cost
8. Expected impact of the system
8.1 Impact on the firm’s organization structure 8.2 Impact on the firm’s operations
8.3 Impact on the firms resources 9. General implementation plan
10. Summary
Outline of an Implementation
Outline of an Implementation
Proposal
Proposal
Implementation Phase
Implementation Phase
Acquire and integrate the physical and
Acquire and integrate the physical and
conceptual resources to produce a
conceptual resources to produce a
working system
working system
Steps for the Implementation
Steps for the Implementation
Phase
Phase
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
Plan the implementation
Announce the implementation
Control
Cutover the new system
Obtain the
hardware resources Obtain the software
resources
Prepare the database
Educate the
participants and users Prepare the physical facilities Control 1. 1. 2. 2. 3 3 4 4 5 5 6 6 7 7 8.
The Implementation Phase
The Implementation Phase
MIS Steering CommitteeMIS Steering Committee ManagerManager Information SpecialistsInformation Specialists
Outline of a Request for
Outline of a Request for
Proposal
Proposal
1. Letter of transmittal
2. System objective and applicable constraints 3. System design
3.1 Summary description 3.2 Performance criteria
3.3 Equipment configuration
3.4 Summary system documentation 3.5 Estimated transaction volume
3.6 Estimated file size 4. Installation schedule
Outline of Supplier Proposal
Outline of Supplier Proposal
1. Letter of transmittal
2. Summary of recommendations 3. Advantages
4. Equipment configuration 5. Equipment specifications
5.1 Performance data 5.2 Prices
6. Satisfaction and performance criteria 7. Delivery schedule
Cutover Approaches
Cutover Approaches
Old System
Old System New System Immediate cutover
Phased cutover Parallel cutover
Pilot System
Immediate
Old System New System
Phased
New system Old System
Parallel
Time
Pilot
Use Phase
Use 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 project By internal auditor (a different one from the project
team member)
team member)
3. Maintain the system
3. Maintain the system
» Correct errorsCorrect errors » Keep currentKeep current
» ImproveImprove
4. Prepare reengineering proposal
4. Prepare reengineering proposal
5. Approve or disapprove reengineering
5. Approve or disapprove reengineering
The Use
The Use
Phase
Phase
Control Use the system
Audit the system
Maintain the system
Prepare
re-engineering proposal
Approve or disapprove the reengineering proposal
MIS Steering Committee Manager Information Specialists
1 2
3
4
5
Prototyping
Prototyping
Type I -- Becomes operational systemType I -- Becomes operational system
Type II -- Serves as a blueprintType II -- Serves as a blueprint
Development of a Type I Prototype
Development of a Type I Prototype
1.
1.
2.
2.
3.
3.
4.
4.
N
N
Identify user needs
Identify user needs
Develop a prototype
Develop a prototype
Prototype
Prototype
acceptable?
acceptable?
Y
Y
Use the prototype
Use the prototype
Developme
Developme
nt of a
nt of a
Type II
Type II
Prototype
Prototype
N N N N Identify user Identify user needs needs Develop a Develop a prototype prototypeCode the
Code the
operational system
operational system
Test the
Test the
operational system
operational system
Use the
Use the
The Attraction of
The Attraction of
Prototyping
Prototyping
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.
Potential Pitfalls of Prototyping
Potential Pitfalls of Prototyping
The haste to deliver the prototype may produce The haste to deliver the prototype may produce
shortcuts in problem definition, alternative evaluation,
shortcuts in problem definition, alternative evaluation,
and documentation.
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.
Applications That Are
Applications That Are
Good Prospects for
Good Prospects for
Prototyping
Prototyping
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
Rapid Application Development
Rapid Application Development
(RAD)
(RAD)
Information engineering (IE)Information engineering (IE)
Key ingredientsKey ingredients
– Management should be experimenters or early Management should be experimenters or early
adapters
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 systems RAD and the SLC are applications of the systems approach
approach
Tools are mainly 4th generation languages and Tools are mainly 4th generation languages and CASE tools
CASE tools
Information strategy planning (ISP) Business area analysis (BAA)
Rapid application development (RAD)
.
Strategic overview of the information needed to run an enterprise as efficiently as possible Data model Design of records used by specific procedures
Strategic overview of the functions and goals of an enterprise
The process needed to operate the enterprise and how they interrelate
Design of
procedures for specific
applications
Rapid Application Development is an
Integral Part of Information Engineering
Data
Activiti es
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 are
redesign are
1) reverse engineering
1) reverse engineering
2) restructuring
2) restructuring
3) reengineering
3) reengineering
Reverse Engineering
Reverse Engineering
Reverse Engineering Produces Documentation on Successively
Reverse Engineering Produces Documentation on Successively
Higher Levels but Leaves the System Unchanged
Higher Levels but Leaves the System Unchanged
Reverse
Reverse
Engineering
Restructuring
Restructuring
Planning Phase
Restructuring Restructuring Restructuring Restructuring
Analysis Phase
Design Phase
Implementation Phase
Reengineering
Reengineering
Reverse Engineering
Reverse
Engineering ReverseEngineering ReverseEngineering
Forward Engineering
Forward Engineering
Forward Engineering
Forward Engineering
Planning Phase
Analysis Phase
Design Phase
Implementation Phase
Selection of BPR
Selection of BPR
Components
Components
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 appropriate
technique would be appropriate
Functional Quality
(What?)
Good
Technical Quality (How?)
Poor Poor
Good
Selection of BPR Components
Reverse Engineer Restructure
Do Nothing
Forward
Engineer Reengineer
SLC, Prototyping, RAD, and
SLC, Prototyping, RAD, and
BPR in Perspective
BPR in Perspective
SLC, prototyping, and RAD are all SLC, prototyping, and RAD are all
methodologies
methodologies
– Recommended ways of implementing a Recommended ways of implementing a
computer-based system
computer-based system
BPR revamps systems that were BPR revamps systems that were
implemented with computer technology that
implemented with computer technology that
has become obsolete
has become obsolete
Summary
Summary
System Life CycleSystem Life Cycle
– PlanningPlanning – AnalysisAnalysis – DesignDesign
– ImplementationImplementation – UseUse
Cycle management responsibilityCycle management responsibility Other methodologiesOther methodologies
