1. Chapter 7 System Life Cycle Methodologies
MANAGEMENT INFORMATION SYSTEMS 8/E
Raymond McLeod, Jr. and George Schell
Chapter 7
System Life Cycle
Methodologies
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Copyright 2001 Prentice-Hall, Inc. 1

2. The Systems Life Cycle (SLC)
Methodology
Recommended way of doing something
An application of the systems approach to the task of developing and using a computer-based system
Often called waterfall approach
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3. Phases in the SDLC 1) Planning 2) Analysis 3) Design 4) Implementation
5) Use
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4. The System Development Life Cycle (SDLC)
SDLC is the phrase that encompasses the planning, analysis, design, and implementation phases of the system life cycle
Who participates
IS personnel
User
Information specialists can consult
Traditional
Information specialists working with users.
A new strategy: Outsourcing
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5. Life Cycle Management An upward migration Executive responsibility
MIS steering committee
Functions
Set policy
Control the purse strings
Resolve conflicts
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6. Managers of Systems Life Cycles are Arranged in a Hierarchy
Executives
MIS Steering
Committee
Marketing
Project leader -Warehouse location model team
Project leader
ISDN
system team
Manufacturing
Project leader
MRP 11 team
Project leader
Credit approval
system team
Finance
Human
Resources
Project leader
HRIS team
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7. Main Advantages of the Steering Committee
Total firm support
Projects will be characterized by good planning and control
Establishes policies, provides fiscal control, and resolves conflicts
Since the steering committee will probably not get involved with the details of the work, a project team is usually appointed.
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8. Planning Phase Benefits Define scope of the project
Spot potential problems
Arrange tasks in sequence
Provide basis for control
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9. Steps 1. Recognize problem (the trigger) 2. Define problem
3. Set objectives
4. Identify constraints
Recall that objectives, standards, and constraints are problem-solving elements.
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10. Steps (cont.) 5. Conduct feasibility study (TENLOS) Technical
Economic return
Noneconomic return
Legal and ethical
Operational
Schedule
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11. Steps (cont.) 6. Prepare study project proposal
Goes to MIS steering committee
7. Approve or disapprove (go/no go)
Key questions?
1. Will the system accomplish its goals?
2. Is this the best way to go about it?
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12. Steps (cont.) 8. Establish a control mechanism Think in terms of:
1. What
2. Who
3. When (Person-months versus calendar months)
PERT and CPM network diagrams
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13. Conduct a feasibility study
The Planning Phase
MIS Steering Comm Manager Systems Analyst
Recognize the
problem 1.
Define the
problem 2.
Set system objectives 3.
Consult 4.
Identify system
constraints
Conduct a feasibility study 5.
Prepare a system study proposal 6. 7.
Approve or disapprove the study project
Establish a control mechanism 8.
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14. 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)
8. Summary
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15. A Project Schedule 0.75 0.25 Time Estimate Subtask Responsibility
Functional System: Marketing
Subsystem: Product
Model: Product Deletion
Time Estimate
(Person Months)
Subtask
Responsibility
1. Identify deletion criteria
2. Identify output information requirements
Systems analyst
Product manager
Network specialist
0.75
0.25
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16. Project Schedule (cont.)
3. Identify input data Systems analyst
requirements DBA
4. Prepare new system Systems analyst
documentation
5. Design network Network specialist
6. Design database DBA
7. Review design Product manager
Systems analyst
8. Prepare program Programmer
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17. Project Schedule (cont.)
9. Code program Programmer
10. Test program Programmer
Operations staff
11. Approve program Product manager
VP of marketing
12. Prepare database DBA
13. Educate users Systems analyst
14. Cutover to model Operations staff
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18. Analysis Phase Steps 1. Announce 2. Organize project team
Reasons for project
Purpose: inform and counteract fear
2. Organize project team
User(s)
Specialists
Define roles
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19. Analysis Phase (cont.) 3. Define information needs Methods
Personal interview (the preferred method)
Observation
Record search (includes review of existing documentation)
Surveys
A project directory can be maintained as an encompassing set of documentation to describe the system
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20. Analysis Phase (cont.) 4. Define system performance criteria
5. Prepare design proposal
(Compare to system study proposal)
6. Approve or disapprove the design project
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21. MIS Steering Committee
The Analysis Phase
MIS Steering Committee
Manager
Systems Analyst
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.
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22. 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
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23. The Design Phase MIS Steering Committee Manager Systems Analyst 1. 2.
Prepare the detailed design system
The Design Phase 2.
Identify alternate system configurations 3.
Evaluate system configurations 4.
Select the best configuration 5.
Prepare the implementation proposal
Approve or disapprove the system implementation 6.
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24. Design Phase 1. Prepare detailed design
Structured design (top down)
System level
Subsystem level
Documentation tools
2. Identify alternate system configurations
Refine to a manageable set
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25. 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
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26. Data Flow Diagram of Four Data Processing Subsystems
Sales orders
Customers
Accepted orders
Rejected sales
order notices
1.1
Order
Entry
Order log
removals file
Filled items
1.2
Inventory
Payments by
customers
Statements
Invoices
Inventory
ledger data
1.3
Billing
Purchasing
data
1.4
Accounts
Receivable
Billed orders 2
Received items
Receivables ledger data 2 3
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27. Data Flow Diagram of Order Entry System
Sales orders
Edit rejects
Sales order
edit rejects
Customer
1.1.1
Edit
order
data
Edited orders
Rejected
sales order
notices
Customer
credit file
1.1.2
Compute
credit
check
Credit data
Accepted
orders
1.1.3
Log in
orders
Edited and checked orders
1.2
Sales order
credit rejects
Credit rejects
Order data
1.1.4
Mark
filled
orders
Completed orders
Date filled
1.3
Order log
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28. Hardware Choices Make Possible Multiple System Configurations
System Elements
Alternatives
Input
CRT terminal
Hardcopy terminal
OCR
Order log
Magnetic tape
DASD
Customer credit file
Magnetic tape
DASD
Rejected orders file
Magnetic tape
DASD
Accepted orders file
Magnetic tape
DASD
Completed orders file
Magnetic tape
DASD
Rejected orders notice
Printer
CRT terminal
Hardcopy terminal
Batch
Processing
Online
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29. Alternatives Selected for Detailed Study
Alternative Input
Order
Log
Customer Credit File
Accepted & Rejected Orders File
Completed Orders File
Rejected Orders Notice 1.
Scanner
Magnetic tape
Magnetic tape
Magnetic tape
Magnetic tape
Printer 2.
Keyboard terminal
Magnetic tape
Magnetic tape
Magnetic tape
Magnetic tape
Printer 3.
Magnetic tape
Hardcopy terminal
Keyboard terminal
Magnetic tape
Magnetic tape
Magnetic tape
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30. Design Phase (cont.) 3. Evaluate configurations
4. Select best configuration
5. Prepare implementation proposal
6. Approve or disapprove the system implementation
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31. Outline of an Implementation Proposal
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
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32. Implementation Phase
Acquire and integrate the physical and conceptual resources to produce a working system
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33. Steps for the Implementation 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
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34. The Implementation Phase
MIS Steering Committee
Manager
Information Specialists
Plan the implementation 1. 2.
Announce the implementation 3
Obtain the
hardware resources
Control
Control 4
Obtain the software
resources 5
Prepare the database 6
Prepare the
physical facilities 7
Educate the
participants and users 8.
Cutover the new system
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35. Outline of a Request for 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
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36. 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
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37. Cutover Approaches Pilot Old System Immediate Old System Phased
Immediate cutover
Pilot
System
Phased cutover
Parallel cutover
Immediate
Old System
New System
Phased
New System
Old System
Old System
Parallel
New system
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Time 38

38. Use Phase 1. Use 2. Audit (post implementation review)
By information specialist(s)
By internal auditor (a different one from the project team member)
3. Maintain the system
Correct errors
Keep current
Improve
4. Prepare reengineering proposal
5. Approve or disapprove reengineering
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39. The Use Phase 2 1 3 4 5 MIS Steering Committee Manager
Information Specialists 2
Audit the
system 1
Use the
system
Control 3
Maintain
the
system 4
Prepare
re-
engineering
proposal
Approve or disapprove the
reengineering proposal 5
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40. Prototyping Type I -- Becomes operational system
Type II -- Serves as a blueprint
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41. Development of a Type I Prototype1.
Identify user needs 2.
Develop a prototype N
Prototype acceptable? 3. Y 4.
Use the prototype
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42. Development of a Type II Prototype
Identify user needs
Development of a Type II Prototype
Develop a prototype N
Prototype acceptable? Y
Code the operational system N
Test the operational system
System acceptable? Y
Use the operational system
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43. The Attraction of Prototyping
Communications between the systems analyst and user are improved.
The analyst can do a better job of determining the user’s needs.
The user plays a more active role in system development.
The information specialists and the user spend less time and effort in developing the system.
Implementation is much easier because the user knows what to expect.
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44. Potential Pitfalls of Prototyping
The haste to deliver the prototype may produce shortcuts in problem definition, alternative evaluation, and documentation.
The users may get so exited about the prototype that they have unrealistic expectations of the operational system.
Type I prototypes might not be as efficient as systems coded in a programming language.
The computer-human interface provided by certain prototyping tools may not reflect good design techniques.
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45. Applications That Are Good Prospects for Prototyping
High risk
Considerable user interaction
Large number of users
A need for quick delivery
An expected short use phase of the system
An innovative system
Unpredictable user behavior
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46. Rapid Application Development (RAD)
Information engineering (IE)
Key ingredients
Management should be experimenters or early adapters
Specialized teams
Methodologies (RAD life cycle)
Tools (I-CASE, 4GLs)
RAD and the SLC are applications of the systems approach
Tools are mainly 4th generation languages and CASE tools
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47. Rapid application development
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
Information
strategy
planning
(ISP)
Business area
analysis
(BAA)
Design of
procedures for
specific
applications
Rapid application development
(RAD) .
Data
Activities
Rapid Application Development is an
Integral Part of Information Engineering
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48. Business Process Redesign (BPR)
Often used to react to systems that can no longer function adequately in the current business environment of the firm (legacy systems fall into this category)
Three techniques for business process redesign are
1) reverse engineering
2) restructuring
3) reengineering
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49. Reverse Engineering
Reverse Engineering Produces Documentation on Successively Higher Levels but Leaves the System Unchanged
Reverse
Reverse
Reverse
Reverse
Engineering
Engineering
Engineering
Engineering
Planning
Phase
Analysis
Phase
Design
Phase
Implementation Phase
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50. Restructuring Planning Phase Analysis Phase Design Phase
Implementation
Phase
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51. Reengineering Planning Phase Analysis Phase Design Phase
Reverse
Engineering
Reverse
Engineering
Reverse
Engineering
Reverse
Engineering
Forward
Engineering
Forward
Engineering
Forward
Engineering
Forward
Engineering
Planning
Phase
Analysis
Phase
Design
Phase
Implementation
Phase
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52. Selection of BPR Components
Based upon functional quality
What the system does
Based upon technical quality
How the system does its job
The relationship between these two characteristics suggest which BPR technique would be appropriate
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53. Selection of BPR Components
Reverse
Engineer
Restructure
Do Nothing
Good
Functional
Quality
(What?)
Forward
Engineer
Poor
Reengineer
Poor
Good
Technical Quality
(How?)
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54. SLC, Prototyping, RAD, and BPR in Perspective
SLC, prototyping, and RAD are all methodologies
Recommended ways of implementing a computer-based system
BPR revamps systems that were implemented with computer technology that has become obsolete
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55. Summary System Life Cycle Cycle management responsibility
Planning
Analysis
Design
Implementation
Use
Cycle management responsibility
Other methodologies
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