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Chapter 14

Chapter 14. Implementing and Maintaining the System. Learning Objectives. Understand the activities associated with the system implementation phase of the SDLC Understand the range of appropriate test procedures for a given application

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Chapter 14

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  1. Chapter 14 Implementing and Maintaining the System CCSB223/SAD/CHAPTER14

  2. Learning Objectives • Understand the activities associated with the system implementation phase of the SDLC • Understand the range of appropriate test procedures for a given application • Identify and select the most suitable conversion strategy for a new application CCSB223/SAD/CHAPTER14

  3. Learning Objectives • Understand the various types of user and system documentation • Understand the activities and constraints associated with the systems maintenance phase of the SDLC CCSB223/SAD/CHAPTER14

  4. What is System Implementation? • Activities that ensure the new system is fully functional and operational • Activities that turn over control of the new system to the end users CCSB223/SAD/CHAPTER14

  5. System Implementation • Application testing and user acceptance • User training and final documentation • System installation and conversion CCSB223/SAD/CHAPTER14

  6. Application Testing • Testing categories • Code inspection • Structured walk-through • Desk check • Module testing CCSB223/SAD/CHAPTER14

  7. Table 14-1. Classification of Software Tests CCSB223/SAD/CHAPTER14

  8. Code Inspection • Inspect the actual code for the occurrence of certain types of programming errors • Focus on errors that may not be syntactically or grammatically incorrect but may cause the logic of the code to fail CCSB223/SAD/CHAPTER14

  9. Figure 14-1. Excerpt From a Formal Code Inspection Checklist for C++ CCSB223/SAD/CHAPTER14

  10. Structured Walkthrough • To test whether the code actually performs the functions intended by the designer • Close examination of the embedded logic in the code CCSB223/SAD/CHAPTER14

  11. Desk Check • Focuses on the actual execution of the code • One or more programmers who are not responsible for the actual writing of the codes work through a hard copy of source code CCSB223/SAD/CHAPTER14

  12. Module Testing • Also referred to as Unit Test • Focuses on ascertaining the successful execution of each application module prior to integrating it with other tested modules • One of the primary black-box testing methods • Test Driver is written to facilitate the test CCSB223/SAD/CHAPTER14

  13. Stub Testing • Top-down testing scenario • The highest-level control module is tested first • The lower-level modules are simulated by a program stub designed to simply accept control from a high-level module and return it back to that module CCSB223/SAD/CHAPTER14

  14. Figure 14-2. Stub Testing Using a Top-Down Approach CCSB223/SAD/CHAPTER14

  15. Integration Testing • Focus on testing the behavior of an entire group of modules to identify errors that either were not, or could not be detected at the unit level CCSB223/SAD/CHAPTER14

  16. Integration Testing • Integration strategies • All at once (big-bang) • Top-down • Bottom-up • Critical piece first CCSB223/SAD/CHAPTER14

  17. Figure 14-3. Combined Module and Integration Testing Strategy CCSB223/SAD/CHAPTER14

  18. System Testing • Focus on the behavior of the entire system • The goal is to have no errors or anomalies remaining • Build-and-smoke test CCSB223/SAD/CHAPTER14

  19. User Acceptance Test • User verifies that the delivered and installed product is ready to be put into production use • Alpha Test (verification test) • Done by the client at the developer’s site • Beta Test (validation test) • Conducted by the end users at their own site CCSB223/SAD/CHAPTER14

  20. User Acceptance Test • Script • Designed to verify that the major functions are properly operating in their most common mode • A testing script is hierarchically organized by subsystem and function CCSB223/SAD/CHAPTER14

  21. Table 14-2. The 16 Commandments of User Acceptance Testing CCSB223/SAD/CHAPTER14

  22. Installing the System • Tasks: • System conversion • Final documentation • End user training CCSB223/SAD/CHAPTER14

  23. System Conversion • Direct conversion • The old system is simply turned off, and the new system is turned on in its place • Should be considered only in extreme circumstances where no other conversion strategy is viable • Also referred to as slam dunk or cold-turkey strategy CCSB223/SAD/CHAPTER14

  24. System Conversion • Parallel Conversion • The old and new systems are run simultaneously until the end users are fully satisfied that the new system is functioning correctly and the old system is no longer necessary CCSB223/SAD/CHAPTER14

  25. System Conversion • Pilot Conversion • Allows for the conversion to the new system, using either direct or parallel method, at a single location CCSB223/SAD/CHAPTER14

  26. System Conversion • Phased Conversion • Allows for the new system to be brought on-line as a series of functional components that are logically ordered so as to minimize disruption to the end users and the flow of business CCSB223/SAD/CHAPTER14

  27. Figure 14-4. Comparison of System Conversion Strategies CCSB223/SAD/CHAPTER14

  28. Table 14-3. General Documentation Deliverable Guidelines for SDLC CCSB223/SAD/CHAPTER14

  29. Figure 14-5. Example of an On-line Help System CCSB223/SAD/CHAPTER14

  30. User Documentation • To provide the end users with a detailed and highly organized description of how to interact with the system • On-line documentation (context-sensitive help) CCSB223/SAD/CHAPTER14

  31. User Documentation • Topics and functions • Procedure • General reference • Tutorial CCSB223/SAD/CHAPTER14

  32. Figure 14-6. Example of a Context-Sensitive Help System CCSB223/SAD/CHAPTER14

  33. System Documentation • Describe the design specification, the internals of the system, the as-built program code, and the functionality of all modules • To assist and support personnel responsible for maintaining the final system CCSB223/SAD/CHAPTER14

  34. User Training and Support • User training design and content • One-size-fits-all training program is not a desirable structure for training • Users need to be trained on how to use the system to perform their respective jobs CCSB223/SAD/CHAPTER14

  35. User Training and Support • User training methods and delivery • Traditional classroom • One-on-one training • Self-paced or computer-based training • Training schedule must be closely linked to the conversion strategy CCSB223/SAD/CHAPTER14

  36. Post-Implementation Activities • To correct errors or faults in the system • Provide changes to affect performance improvement • Adapt the system to changes in the operating environment CCSB223/SAD/CHAPTER14

  37. Figure 14-7. Relative Distribution of Costs Across SDLC Activities CCSB223/SAD/CHAPTER14

  38. System Maintenance • Change requests • Identifying and implementing changes to the system that add or enhance functionality • Change control steering committee CCSB223/SAD/CHAPTER14

  39. Figure 14-8. Sample Content for a Software Change Request CCSB223/SAD/CHAPTER14

  40. System Maintenance • Corrective Maintenance • Fix bugs and logical errors not detected during the implementation testing period • Adaptive Maintenance • Modifying existing functions or adding new functionality to accommodate changes in the operating environment CCSB223/SAD/CHAPTER14

  41. System Maintenance • Perfective Maintenance • Changes made to an existing system to improve the performance of a function or interface • Preventive Maintenance • Activities intended to reduce the chances of a system failure or extend the capacity of a current system’s useful life CCSB223/SAD/CHAPTER14

  42. System Maintenance • Preventive maintenance activities • Hardware maintenance to keep electromechanical equipment operating correctly • Replacement of hardware components to keep the equipment up to current specifications • Updating of system software • Testing and analysis of system reports • Maintenance of system documentation CCSB223/SAD/CHAPTER14

  43. System Maintenance • System Maintenance Costs • There is a direct link between the cost of absolute availability and the cost of downtime • Maintenance can account for a significant portion of the total IS budget CCSB223/SAD/CHAPTER14

  44. System Maintenance • Cost Estimation of Downtime • Productivity loss • Downtime that has a negative impact on individual or workgroup productivity • Productivity Loss = (# of Affected Users) x (Percentage Effect on Productivity / 100) x (Average Burdened Salary per Hour) x (Hours of Downtime) CCSB223/SAD/CHAPTER14

  45. System Maintenance • Cost Estimation of Downtime • Business loss • Downtime that affects transactions or result in customer losses • Business Loss = (# of Affected Users) x (Percentage Effect on Productivity / 100) x (Average Profit per Employee Hour) x (Hours of Downtime) • Or (# of Transactions per Hour) x (Percentage of Affected Transactions / 100) x (Average Profit per Transaction) x (Hours of Downtime) - End - CCSB223/SAD/CHAPTER14

  46. Chapter Summary • When you first experience the world of SAD, the details of the methodology in place may differ from what you learned from this text. • The underlying concepts, principles, and objectives will most certainly be consistent with what you have learned, and you will be able to adapt easily to the new environment. CCSB223/SAD/CHAPTER14

  47. Chapter 14 End of Chapter CCSB223/SAD/CHAPTER14

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