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ch10.ppt Presentation Transcript

  • 1. Chapter 10: Systems Development
  • 2. Objectives
    • Describe the systems development life cycle, who participates in it and why it is important
    • Discuss systems development tools
    • Understand how systems development projects are investigated
  • 3. Objectives
    • Describe how an existing system can be evaluated
    • Discuss what is involved in planning a new system
    • List the steps to implement a new or modified system
    • Describe the importance of updating and monitoring a system
  • 4. Chapter Content
    • An Overview of Systems Development
    • Tools and Techniques for Systems Development
    • Systems Investigation
    • Systems Analysis
  • 5. Chapter Content
    • Systems Design
    • Systems Implementation
    • Systems Maintenance and Review
  • 6. An Overview of Systems Development
    • Systems development process
      • Includes a wide range of projects
        • Purchasing a small program
        • Installing a huge system including hardware, software, communications equipment, and personnel
      • Typically called a systems development life cycle (SDLC)
  • 7. An Overview of Systems Development
    • Systems investigation and analysis
      • Looks at the existing system and determines if it can and should be improved
    • Systems design and implementation
      • Selecting and planning the best solution
      • Modifying an existing system or developing a new one, placing the best solution into effect
    • Maintenance and review
      • Evaluating the results of the solution
      • Makes sure that the new or modified system is operating as intended
  • 8. An Overview of Systems Development
  • 9. Participants in Systems Development
    • System stakeholders
      • Individuals who will benefit from systems development project
    • Users
      • Individuals who will be interacting with the system on a regular basis
    • Managers
      • People most capable of initiating and maintaining change
  • 10. Participants in Systems Development
    • Systems development specialists
      • Project leader
        • Individual in charge of the systems development effort
      • Systems analyst
        • Specializes in analyzing and designing systems
      • Software engineer or computer programmer
        • Responsible for modifying or creating programs to satisfy user requirements
      • Computer systems management
        • Includes the chief information officer (CIO) and other technicians
  • 11. Participants in Systems Development
  • 12. Why Start A Systems Development Project?
    • Several reasons:
      • Problems with existing systems
      • Mergers
      • Competition
      • Pressure from government agencies
  • 13. Why Start A Systems Development Project?
    • Creative analysis
      • Investigating new approaches to existing problems
    • Critical analysis
      • Being skeptical and doubtful
      • Questioning whether or not the current computer system is still effective and efficient
    • Systems development process
      • Begins with gathering information on users’ needs
  • 14. Systems Development Planning
    • System development planning
      • Translation of organized or individual goals into systems development initiatives
  • 15. End-User Systems Development
    • End-user systems development
      • Development of computer systems by individuals outside of the formal planning and departmental structure
      • Range from small to significant
        • Software routine to merge data with form letters
        • Customer contact databases
  • 16. End-User Systems Development
  • 17. Tools and Techniques for Systems Development
    • Systems development tools
      • Can greatly simplify the systems development process
      • Include
        • Computer-aided software engineering tools (CASE)
        • Flowcharts, decision tables
        • Project management software
        • Prototyping
        • Outsourcing and object-oriented systems development
  • 18. Computer-Aided Software Engineering
    • Software engineering
      • Employs computer-aided software engineering (CASE) tools
    • CASE tools
      • Automate many systems development tasks
      • Allow more than one person to work on the same system at the same time via a multiuser interface
  • 19. Computer-Aided Software Engineering
  • 20. Flowcharts
    • Chart the path from a starting point to the final destination
    • Can display various amounts of detail
    • When developing a system
      • General flowchart describes the overall purpose and structure of the system
  • 21. Flowcharts
  • 22. Flowcharts
  • 23. Decision Tables
    • Can be used as an alternative to or in conjunction with flowcharts
    • In general, a decision table displays
      • The various conditions that could exist
      • The different actions that the computer should take
  • 24. Decision Tables
  • 25. Project Management Tools
    • Purpose is to plan, monitor, and control necessary development activities
    • Program Evaluation and Review Technique (PERT)
      • Creates three time estimates for an activity
        • The shortest possible time
        • The most likely time
        • The longest possible time
    • Gantt charting
      • A grid that lists activities and deadlines
    • Project crashing
      • Reducing project completion time
  • 26. Project Management Tools
  • 27. Project Management Tools
  • 28. Prototyping
    • The creation of a preliminary model or version of a major subsystem
    • Iterative approach to systems development
      • Each phase of the SDLC is repeated several times (iterated)
  • 29. Prototyping
  • 30. Outsourcing
    • Use of outside company to take over portions of its workload
    • Challenges and disadvantages
      • Internal experience and loyalty can suffer
      • People can lose jobs and be very emotional
      • Once outside company leaves, internal employees lack experience
      • Difficult to compete when using the same companies
  • 31. Object-Oriented Systems Development
    • An extension of object-oriented programming
    • Can be used during all phases of systems development
    • Organizations
      • Have saved time and money using the object-oriented approach to systems development
    • Objects can be diagrammed
      • Actor and use case
  • 32. Object-Oriented Systems Development
  • 33. Systems Investigation
    • Overall purpose
      • Determine whether objectives of existing system satisfy the goals of the organization
    • Attempts to answer the following questions
      • What primary problems might a new or enhanced system solve?
      • What opportunities might a new or enhanced system provide?
      • What new hardware, software, databases, telecommunications, personnel, or procedures will improve the existing system or are required for a new system?
      • What are the potential costs?
      • What are the associated risks?
  • 34. Feasibility Analysis
    • Technical feasibility
      • Concerned with whether or not hardware/software can be acquired or developed to solve the problem
    • Economic feasibility
      • Determines if the project makes financial sense
    • Legal feasibility
      • Determines whether laws or regulations may prevent or limit a systems development project
  • 35. Feasibility Analysis
    • Operational feasibility
      • Measure of whether or not the project can be put into action or operation
    • Schedule feasibility
      • Determines if the project can be completed in a reasonable amount of time
  • 36. Feasibility Analysis
  • 37. Systems Analysis
    • Attempts to understand how the existing system helps solve the problem identified in systems investigation
    • Overall emphasis
      • To gather data on the existing system and the requirements for the new system
      • To consider alternative solutions to the problem and the feasibility of the solutions
  • 38. General Analysis Considerations
    • Formalized analysis procedure involves
      • Collecting appropriate data
      • Analyzing the data
      • Determining new system requirements and project priorities
  • 39. Collecting Data
    • Purpose
      • To seek additional information about problems identified during systems investigation
    • Techniques
      • Interviews
      • Direct observation
      • Outputs
      • Questionnaires
      • Other Data Collection Methods
  • 40. Collecting Data
  • 41. Collecting Data
  • 42. Requirements Analysis
    • Purpose
      • To determine user, stakeholder, and organizational needs
    • Tools and techniques
      • Asking Directly
      • Critical Success Factors
      • Joint Application Development
      • Rapid Application Development
  • 43. Requirements Analysis
  • 44. Systems Design
    • Overall purpose
      • To select and plan a system that meets the requirements needed to deliver the problem solution
    • Results
      • A new or modified system
  • 45. Generating Systems Design Alternatives
    • First step of design
      • Investigate alternatives for all components
    • Request for information (RFI)
      • Asks a computer systems vendor to provide information about its products or services
    • Request for quotes (RFQ)
      • Asks a computer systems company to give prices for its products or services
    • Request for proposal (RFP)
      • Generated during systems development
  • 46. Generating Systems Design Alternatives
  • 47. Evaluating and Selecting a Systems Design
    • Evaluate design alternatives
    • Select the best solution for supporting your needs
      • Cost comparisons
      • Hardware performance
      • Delivery dates
      • Price
      • Storage capabilities
      • Training
      • Computer speed
  • 48. The Contract
    • Most vendors provide standard contracts
      • Designed to protect the vendor, not the organization buying the equipment
    • Organizations are creating their own contracts, clearly stating
      • Equipment and software specifications
      • Training
      • Installation
      • Maintenance
  • 49. Systems Implementation
    • Includes
      • Hardware acquisition
      • Software acquisition or development
      • User preparation
      • Hiring and training of personnel
      • Site and data preparation
      • Installation, testing, startup, and user acceptance
  • 50. Acquiring Hardware
    • Most people and organizations acquire hardware and computers by
      • Purchasing, leasing, or renting computer resources from a computer systems vendor
    • “Pay as you go computing”
      • Organization pays only for the computer power it uses
  • 51. Selecting and Acquiring Software: Make, Buy, or Rent
    • Program development life cycle
      • Program specification
        • Description of what the software must accomplish
      • Algorithm
        • Step-by-step sequence of computer instructions
      • S yntax errors
        • Errors in the use of the programming language syntax
      • Logic errors
        • Errors in the programming logic
  • 52. Selecting and Acquiring Software: Make, Buy, or Rent
    • Software as a service (SaaS)
      • Software resides on vendor’s server
    • Application service provider (ASP)
      • Develops, maintains, stores software and makes it available over the Internet
  • 53. Acquiring Database and Telecommunications Systems
    • A database is one of the most important parts of system development
      • Many projects involve a database
      • May require both hardware and software acquisition
    • Telecommunications is one of the fastest growing business applications
      • May require both hardware and software acquisition
  • 54. Acquiring Database and Telecommunications Systems
  • 55. User Preparation
    • Readying users and stakeholders for the new or modified system
    • Can include
      • Marketing
      • Training
      • Documentation
      • Support
  • 56. User Preparation
  • 57. Computer Systems Personnel: Hiring and Training
    • Depending on the size of your new system, personnel may have to be
      • Trained
      • Hired
    • Systems may need
      • Systems manager
      • Programmers
      • Data entry operators
    • The success of any computer system depends on the way it is used by the personnel within the organization
  • 58. Site Preparation
    • Location of the new system needs to be prepared
    • For a small system
      • May mean rearranging the furniture
    • Larger systems
      • May require special wiring and air conditioning
  • 59. Data Preparation
    • Converting manual files into computer files
    • Data conversion
      • May be required to transform the existing computerized files into the proper format
    • Permanent data
      • Must be placed on a permanent storage device
  • 60. Installation
    • Placing computer equipment on the site and making it operational
    • For a small systems development project
      • May require making room on top of a desk for a new PC
      • Plugging it into a wall outlet
      • Following the manufacturer’s instructions to turn it on
    • Larger projects are usually completed by the manufacturer
  • 61. Testing
    • Unit testing
      • Developing test data that will force the computer to execute every statement in the program
    • System testing
      • Requires the testing of all programs together
    • Volume testing
      • Ensures that entire system can handle a large amount of data under normal operating conditions
  • 62. Testing
    • Integration testing
      • Ensures that new programs can interact with other major applications
    • Acceptance testing
      • Ensures that new or modified system is operating as intended
  • 63. Testing
  • 64. Startup
    • Direct conversion
      • Stopping the old system and starting the new one on a given date
    • Phase-in approach
      • New system is slowly phased in, while old one is slowly phased out
    • Pilot startup
      • Running a pilot or small version of the new system along with the old
  • 65. Startup
  • 66. User Acceptance and Documentation
    • User acceptance document
      • Agreement signed by user that a phase of the complete system is approved
    • Documentation
      • Includes all materials that describe the new or modified system
  • 67. User Acceptance and Documentation
    • Systems documentation
      • Describes the technical aspects of the new or modified system
    • User documentation
      • Describes how the system can be used by noncomputer personnel
  • 68. Systems Maintenance and Review
    • Final steps of systems development
    • Involves checking, changing, and enhancing the system to make it serve the organization better
  • 69. Reasons for Maintenance
    • New requests from stakeholders, users, and managers
    • Bugs or errors in the program
    • Technical and hardware problems
    • Corporate mergers and acquisitions
    • Governmental regulations that require changes in programs
  • 70. Financial Implications of Maintenance
    • For older programs
      • Cost of maintenance can be up to five times greater than cost of development
    • Average programmer
      • Can spend from 50% - over 75% of his/her time maintaining programs
    • Important to keep track of why systems are maintained as well as the cost of maintenance
  • 71. Financial Implications of Maintenance
  • 72. Systems Review
    • Final phase of the systems development life cycle
      • Analyzing systems to make sure that they are operating as intended
    • Two types of review procedures
      • Event-driven review
      • Time-driven review
    • Continuous improvement approach
      • Make changes even when small problems or opportunities arise
  • 73. Summary
    • Phases of the SDLC
      • Investigation, analysis, design, implementation, maintenance, review
    • Common system development tools and techniques
      • CASE tools
      • Flowcharts
      • Decision tables
    • Systems investigation
      • First step in the development of a new or modified computer system
  • 74. Summary
    • Systems analysis
      • The examination of existing systems
    • Systems design
      • Prepares detailed design needs for new system or modifications to the existing one
    • Systems implementation
      • Includes hardware acquisition, software acquisition or development, and user preparation
    • Systems maintenance
      • Involves checking, changing, and enhancing the system