Chap07

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  • Chap07

    1. 1. Chapter 7 <ul><li>System Life Cycle </li></ul><ul><li>Methodologies </li></ul>MANAGEMENT INFORMATION SYSTEMS 8/E Raymond McLeod, Jr. and George Schell Copyright 2001 Prentice-Hall, Inc. 7-
    2. 2. The Systems Life Cycle (SLC) <ul><li>Methodology </li></ul><ul><ul><li>Recommended way of doing something </li></ul></ul><ul><li>An application of the systems approach to the task of developing and using a computer-based system </li></ul><ul><li>Often called waterfall approach </li></ul>7-
    3. 3. Phases in the SDLC <ul><li>1) Planning </li></ul><ul><li>2) Analysis </li></ul><ul><li>3) Design </li></ul><ul><li>4) Implementation </li></ul><ul><li>5) Use </li></ul>7-
    4. 4. The System Development Life Cycle (SDLC) <ul><li>SDLC is the phrase that encompasses the planning, analysis, design, and implementation phases of the system life cycle </li></ul><ul><li>Who participates </li></ul><ul><ul><li>IS personnel </li></ul></ul><ul><ul><li>User </li></ul></ul><ul><ul><li>Information specialists can consult </li></ul></ul><ul><li>Traditional </li></ul><ul><ul><li>Information specialists working with users. </li></ul></ul><ul><ul><li>A new strategy: Outsourcing </li></ul></ul>7-
    5. 5. Life Cycle Management <ul><li>An upward migration </li></ul><ul><li>Executive responsibility </li></ul><ul><li>MIS steering committee </li></ul><ul><ul><li>Functions </li></ul></ul><ul><ul><ul><li>Set policy </li></ul></ul></ul><ul><ul><ul><li>Control the purse strings </li></ul></ul></ul><ul><ul><ul><li>Resolve conflicts </li></ul></ul></ul>7-
    6. 6. 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 7-
    7. 7. Main Advantages of the Steering Committee <ul><li>Total firm support </li></ul><ul><li>Projects will be characterized by good planning and control </li></ul><ul><li>Establishes policies, provides fiscal control, and resolves conflicts </li></ul>Since the steering committee will probably not get involved with the details of the work, a project team is usually appointed. 7-
    8. 8. Planning Phase <ul><li>Benefits </li></ul><ul><ul><li>Define scope of the project </li></ul></ul><ul><ul><li>Spot potential problems </li></ul></ul><ul><ul><li>Arrange tasks in sequence </li></ul></ul><ul><ul><li>Provide basis for control </li></ul></ul>7-
    9. 9. Steps <ul><li>1. Recognize problem (the trigger) </li></ul><ul><li>2. Define problem </li></ul><ul><li>3. Set objectives </li></ul><ul><li>4. Identify constraints </li></ul>Recall that objectives, standards, and constraints are problem-solving elements. 7-
    10. 10. Steps (cont.) <ul><li>5. Conduct feasibility study (TENLOS) </li></ul><ul><ul><li>Technical </li></ul></ul><ul><ul><li>Economic return </li></ul></ul><ul><ul><li>Noneconomic return </li></ul></ul><ul><ul><li>Legal and ethical </li></ul></ul><ul><ul><li>Operational </li></ul></ul><ul><ul><li>Schedule </li></ul></ul>7-
    11. 11. Steps (cont.) <ul><li>6. Prepare study project proposal </li></ul><ul><ul><li>Goes to MIS steering committee </li></ul></ul><ul><li>7. Approve or disapprove (go/no go) </li></ul><ul><ul><li>Key questions? </li></ul></ul><ul><ul><li>1. Will the system accomplish its goals? </li></ul></ul><ul><ul><li>2. Is this the best way to go about it? </li></ul></ul>7-
    12. 12. Steps (cont.) <ul><li>8. Establish a control mechanism </li></ul><ul><ul><li>Think in terms of: </li></ul></ul><ul><ul><ul><li>1. What </li></ul></ul></ul><ul><ul><ul><li>2. Who </li></ul></ul></ul><ul><ul><ul><li>3. When (Person-months versus calendar months) </li></ul></ul></ul><ul><ul><li>PERT and CPM network diagrams </li></ul></ul>7-
    13. 13. Define the problem 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 MIS Steering Comm Manager Systems Analyst 1. 2. 3. 4. 5. 6. 7. 8. Conduct a feasibility study 7-
    14. 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 7-
    15. 15. A Project Schedule Functional System: Marketing Subsystem: Product Model: Product Deletion Subtask Time Estimate (Person Months) Responsibility 1. Identify deletion criteria 2. Identify output information requirements Systems analyst Product manager Systems analyst Network specialist Product manager 0.75 0.25 7-
    16. 16. Project Schedule (cont.) <ul><li>3. Identify input data Systems analyst 0.50 </li></ul><ul><li>requirements DBA </li></ul><ul><li>4. Prepare new system Systems analyst 2.00 </li></ul><ul><li>documentation </li></ul><ul><li>5. Design network Network specialist 1.50 </li></ul><ul><li>6. Design database DBA 0.50 </li></ul><ul><li>7. Review design Product manager 0.25 </li></ul><ul><li>Systems analyst </li></ul><ul><li>8. Prepare program Programmer 1.00 </li></ul><ul><li>documentation </li></ul>7-
    17. 17. Project Schedule (cont.) <ul><li>9. Code program Programmer 1.25 </li></ul><ul><li>10. Test program Programmer 0.75 </li></ul><ul><li>Operations staff </li></ul><ul><li>11. Approve program Product manager 0.50 </li></ul><ul><li>VP of marketing </li></ul><ul><li>12. Prepare database DBA 2.00 </li></ul><ul><li>13. Educate users Systems analyst 0.50 </li></ul><ul><li>14. Cutover to model Operations staff 0.75 </li></ul>7-
    18. 18. Analysis Phase <ul><li>Steps </li></ul><ul><ul><li>1. Announce </li></ul></ul><ul><ul><ul><li>Reasons for project </li></ul></ul></ul><ul><ul><ul><li>Purpose: inform and counteract fear </li></ul></ul></ul><ul><ul><li>2. Organize project team </li></ul></ul><ul><ul><ul><li>User(s) </li></ul></ul></ul><ul><ul><ul><li>Specialists </li></ul></ul></ul><ul><ul><ul><li>Define roles </li></ul></ul></ul>7-
    19. 19. Analysis Phase (cont.) <ul><ul><li>3. Define information needs </li></ul></ul><ul><ul><ul><li>Methods </li></ul></ul></ul><ul><ul><ul><ul><li>Personal interview (the preferred method) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Observation </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Record search (includes review of existing documentation) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Surveys </li></ul></ul></ul></ul>A project directory can be maintained as an encompassing set of documentation to describe the system 7-
    20. 20. Analysis Phase (cont.) <ul><ul><li>4. Define system performance criteria </li></ul></ul><ul><ul><li>5. Prepare design proposal </li></ul></ul><ul><ul><li>(Compare to system study proposal) </li></ul></ul><ul><ul><li>6. Approve or disapprove the design project </li></ul></ul>7-
    21. 21. The Analysis Phase MIS Steering Committee Manager Systems Analyst 7- 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.
    22. 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 7-
    23. 23. Approve or disapprove the system implementation Prepare the detailed design system Identify alternate system configurations Evaluate system configurations Select the best configuration Prepare the implementation proposal 1. 2. 3. 4. 5. 6. MIS Steering Committee Manager Systems Analyst The Design Phase 7-
    24. 24. Design Phase <ul><li>1. Prepare detailed design </li></ul><ul><ul><li>Structured design (top down) </li></ul></ul><ul><ul><ul><li>System level </li></ul></ul></ul><ul><ul><ul><li>Subsystem level </li></ul></ul></ul><ul><ul><li>Documentation tools </li></ul></ul><ul><li>2. Identify alternate system configurations </li></ul><ul><ul><li>Refine to a manageable set </li></ul></ul>7-
    25. 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 7-
    26. 26. Data Flow Diagram of Four Data Processing 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 Statements Invoices Billed orders Receivables ledger data Order log removals file Filled items Inventory ledger data Received items Purchasing data 3 3 2 2 7-
    27. 27. 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 7-
    28. 28. Hardware Choices Make Possible Multiple System Configurations System Elements Alternatives <ul><li>CRT terminal </li></ul><ul><li>Hardcopy terminal </li></ul><ul><li>OCR </li></ul>Input Order log Customer credit file Rejected orders file Accepted orders file Completed orders file Rejected orders notice Processing <ul><li>Magnetic tape </li></ul><ul><li>DASD </li></ul><ul><li>Magnetic tape </li></ul><ul><li>DASD </li></ul><ul><li>Magnetic tape </li></ul><ul><li>DASD </li></ul><ul><li>Magnetic tape </li></ul><ul><li>DASD </li></ul><ul><li>Magnetic tape </li></ul><ul><li>DASD </li></ul><ul><li>Printer </li></ul><ul><li>CRT terminal </li></ul><ul><li>Hardcopy terminal </li></ul><ul><li>Batch </li></ul><ul><li>Online </li></ul>7-
    29. 29. Alternatives Selected for Detailed Study Alternative Input Order Log Customer Credit File Accepted & Rejected Orders File Completed Orders File Rejected Orders Notice 1. 2. 3. Scanner Keyboard terminal Magnetic tape Keyboard terminal Magnetic tape Magnetic tape Magnetic tape Magnetic tape Magnetic tape Magnetic tape Magnetic tape Magnetic tape Magnetic tape Magnetic tape Magnetic tape Printer Printer Hardcopy terminal 7-
    30. 30. Design Phase (cont.) <ul><li>3. Evaluate configurations </li></ul><ul><li>4. Select best configuration </li></ul><ul><li>5. Prepare implementation proposal </li></ul><ul><li>6. Approve or disapprove the system implementation </li></ul>7-
    31. 31. 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 Proposal 7-
    32. 32. Implementation Phase <ul><li>Acquire and integrate the physical and conceptual resources to produce a working system </li></ul>7-
    33. 33. Steps for the Implementation Phase <ul><ul><li>1. Plan implementation </li></ul></ul><ul><ul><li>2. Announce </li></ul></ul><ul><ul><li>3. Obtain hardware resources </li></ul></ul><ul><ul><ul><li>RFP / Written Proposals </li></ul></ul></ul><ul><ul><li>4. Obtain software resources </li></ul></ul><ul><ul><ul><li>&quot;Make or buy&quot; </li></ul></ul></ul><ul><ul><li>5. Prepare database </li></ul></ul><ul><ul><li>6. Prepare physical facilities </li></ul></ul><ul><ul><li>7. Educate participants and users </li></ul></ul><ul><ul><li>8. Prepare cutover proposal </li></ul></ul><ul><ul><li>9. Approve or disapprove cutover to new systsem </li></ul></ul><ul><ul><li>10. Cutover to new system </li></ul></ul>7-
    34. 34. 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. 2. 3 4 5 6 7 8. The Implementation Phase MIS Steering Committee Manager Information Specialists 7-
    35. 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 7-
    36. 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 7-
    37. 37. 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 7-
    38. 38. Use Phase <ul><ul><li>1. Use </li></ul></ul><ul><ul><li>2. Audit (post implementation review) </li></ul></ul><ul><ul><ul><li>By information specialist(s) </li></ul></ul></ul><ul><ul><ul><li>By internal auditor (a different one from the project team member) </li></ul></ul></ul><ul><ul><li>3. Maintain the system </li></ul></ul><ul><ul><ul><li>Correct errors </li></ul></ul></ul><ul><ul><ul><li>Keep current </li></ul></ul></ul><ul><ul><ul><li>Improve </li></ul></ul></ul><ul><ul><li>4. Prepare reengineering proposal </li></ul></ul><ul><ul><li>5. Approve or disapprove reengineering </li></ul></ul>7-
    39. 39. The Use 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 7-
    40. 40. Prototyping <ul><li>Type I -- Becomes operational system </li></ul><ul><li>Type II -- Serves as a blueprint </li></ul>7-
    41. 41. Development of a Type I Prototype 1. 2. 3. 4. N Identify user needs Develop a prototype Prototype acceptable? Y Use the prototype 7-
    42. 42. Development of a Type II Prototype N Identify user needs Develop a prototype Code the operational system Test the operational system Use the operational system Prototype acceptable? System acceptable? Y Y 7- N
    43. 43. The Attraction of Prototyping <ul><li>Communications between the systems analyst and user are improved. </li></ul><ul><li>The analyst can do a better job of determining the user’s needs. </li></ul><ul><li>The user plays a more active role in system development. </li></ul><ul><li>The information specialists and the user spend less time and effort in developing the system. </li></ul><ul><li>Implementation is much easier because the user knows what to expect. </li></ul>7-
    44. 44. Potential Pitfalls of Prototyping <ul><li>The haste to deliver the prototype may produce shortcuts in problem definition, alternative evaluation, and documentation. </li></ul><ul><li>The users may get so exited about the prototype that they have unrealistic expectations of the operational system. </li></ul><ul><li>Type I prototypes might not be as efficient as systems coded in a programming language. </li></ul><ul><li>The computer-human interface provided by certain prototyping tools may not reflect good design techniques. </li></ul>7-
    45. 45. Applications That Are Good Prospects for Prototyping <ul><li>High risk </li></ul><ul><li>Considerable user interaction </li></ul><ul><li>Large number of users </li></ul><ul><li>A need for quick delivery </li></ul><ul><li>An expected short use phase of the system </li></ul><ul><li>An innovative system </li></ul><ul><li>Unpredictable user behavior </li></ul>7-
    46. 46. Rapid Application Development (RAD) <ul><li>Information engineering (IE) </li></ul><ul><li>Key ingredients </li></ul><ul><ul><li>Management should be experimenters or early adapters </li></ul></ul><ul><ul><li>Specialized teams </li></ul></ul><ul><ul><li>Methodologies (RAD life cycle) </li></ul></ul><ul><ul><li>Tools (I-CASE, 4GLs) </li></ul></ul><ul><li>RAD and the SLC are applications of the systems approach </li></ul><ul><li>Tools are mainly 4th generation languages and CASE tools </li></ul>7-
    47. 47. 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 Activities 7-
    48. 48. Business Process Redesign (BPR) <ul><li>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) </li></ul><ul><li>Three techniques for business process redesign are </li></ul><ul><ul><li>1) reverse engineering </li></ul></ul><ul><ul><li>2) restructuring </li></ul></ul><ul><ul><li>3) reengineering </li></ul></ul>7-
    49. 49. Reverse Engineering Reverse Engineering Produces Documentation on Successively Higher Levels but Leaves the System Unchanged Reverse Engineering Engineering Reverse Engineering Reverse Engineering Reverse Planning Phase Analysis Phase Design Phase Implementation Phase 7-
    50. 50. Restructuring Planning Phase Restructuring Restructuring Restructuring Restructuring Analysis Phase Design Phase Implementation Phase 7-
    51. 51. Reengineering Reverse Engineering Reverse Engineering Reverse Engineering Reverse Engineering Forward Engineering Forward Engineering Forward Engineering Forward Engineering Planning Phase Analysis Phase Design Phase Implementation Phase 7-
    52. 52. Selection of BPR Components <ul><li>Based upon functional quality </li></ul><ul><ul><li>What the system does </li></ul></ul><ul><li>Based upon technical quality </li></ul><ul><ul><li>How the system does its job </li></ul></ul><ul><li>The relationship between these two characteristics suggest which BPR technique would be appropriate </li></ul>7-
    53. 53. Functional Quality (What?) Good Technical Quality (How?) Poor Poor Good Selection of BPR Components Reverse Engineer Restructure Do Nothing Forward Engineer Reengineer 7-
    54. 54. SLC, Prototyping, RAD, and BPR in Perspective <ul><li>SLC, prototyping, and RAD are all methodologies </li></ul><ul><ul><li>Recommended ways of implementing a computer-based system </li></ul></ul><ul><li>BPR revamps systems that were implemented with computer technology that has become obsolete </li></ul>7-
    55. 55. Summary <ul><li>System Life Cycle </li></ul><ul><ul><li>Planning </li></ul></ul><ul><ul><li>Analysis </li></ul></ul><ul><ul><li>Design </li></ul></ul><ul><ul><li>Implementation </li></ul></ul><ul><ul><li>Use </li></ul></ul><ul><li>Cycle management responsibility </li></ul><ul><li>Other methodologies </li></ul>7-

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