Analysis & Design of Business Systems - 5


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System Implementation and Operations

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Analysis & Design of Business Systems - 5

  1. 1. Amity School of Business Module- VSystem Implementation & Operation (System Management) 1
  2. 2. Topics Amity School of Business• Activities in implementing a system• Testing and types of testing• Installation Approaches • Direct • Parallel • Single Location • Phased• Training and supporting users• Types of Training Methods• Reason of system implementation failures• Maintenance and types of maintenance • Effective Maintenance • System Enhancement • Quality Assurance
  3. 3. Activities in implementing system Amity School of BusinessSystem implementation and operation ismade up of seven major activities:• Coding• Testing• Installation• Documentation• Training• Support• Maintenance 3
  4. 4. Amity School of BusinessThe purpose of these steps is to convert thefinal physical system specifications intoworking and reliable software and hardware,document the work that has been done, andprovide help for current and future users andcaretakers of the system. 4
  5. 5. 3 group of Activities Amity School of Business• Activities that lead to the system going into operation- – coding, testing, and installation.• Activities that are necessary for successful system operation- – documenting the system and training and supporting users.• Activities that make system ongoing and needed to keep the system working and up-to-date- – maintenance 5
  6. 6. Testing Amity School of Business• Testing is process of executing system with the intent of finding errors to ensure that all aspects of newly designed system are in working order and meeting user requirements.• Theoretically a newly designed system should have all the pieces in working order, but in reality, each piece works independently. Now is the time to put all the pieces into one system and test it to determine whether it meets the user’s requirements. 6
  7. 7. Why System Testing? Amity School of Business• System testing makes a logical assumption that if all the parts of the system are correct, the goal will be successfully achieved.• Cost factor is the driving force behind testing a system.• Inadequate testing or non testing leads to errors that may not appear until months later. 7
  8. 8. Amity School of Business• Inadequate testing may lead two problems: – The time lag between the cause and the appearance of the problem. – The effects of system errors on files and records within the system. – System may not be able to meet user’s all requirement. 8
  9. 9. What is test case? Amity School of Business• It describes an input description and an expected output description.• During testing, conditions are set, required input is given to system and observed output is compared with expected output to know the outcome of test case.• If expected and observed outputs are different, then, there is a failure and it must be recorded properly to find out the reason of failure.• If both are same then there is no failure and program behaved in expected manner.• A good test case has high probability of finding errors. 9
  10. 10. Types of System TestingAmity School of Business• Unit testing• Integration testing• System testing• User Acceptance Testing 10
  11. 11. Unit Testing Amity School of Business• It is the process of taking a module and running it in isolation from rest of the software product by using prepared test cases and comparing actual results with the predicted results. 11
  12. 12. Reasons for Unit testing Amity School of Business• The size of single module is small enough that we can locate the errors fairly easily.• Confusing interactions of multiple errors in widely different parts of the software are eliminated. 12
  13. 13. Integration Testing Amity School of BusinessWhen independent module of software are linked together to form a complete system, integration testing is done to determine that the interface between modules is also correct.• One specific target of integration testing is the interface: whether the parameters match on both sides as to type, permissible ranges, meaning and utilization.• Each time a new module is added as a part of integration testing, the software changes. New data flow paths are established, new I/O occur, and new control logic is invoked. These changes may cause problems with the functions that previously worked flawlessly and to solve these problems integration testing is done. 13
  14. 14. System Testing Amity School of Business• Software is one component of large computer based system. Ultimatly software is incorporated with other system components and thus, a series of special tests are to be conducted to ensure whole system is working correctly.• Software should actually be tested on many different hardware set-ups, memory, processor, operating system, and peripheral 14
  15. 15. Amity School of Business• Response time under various loads and operating conditions.• Measurement of main and disk memory usage.• Time and effort needed to recover from failure should also be noted and compared with specifications. 15
  16. 16. Amity School of BusinessDuring system testing, number of attributesof the software are evaluated that are vital tousers:•Security•Compatibility•Dependability•Documentation 16
  17. 17. User acceptance Testing Amity School of Business When a software is developed for users,it’s put under series of tests to enable auser to validate all requirements. Thediscovered errors are then fixed and betterquality software will be delivered to thecustomers. 17
  18. 18. Installation Amity School of Business• The process of moving from the current information system to the new one is called installation. 18
  19. 19. Approaches to Installation Amity School of BusinessFour approaches of installation are there:• Direct Installation• Parallel Installation• Single Location• Phased Installation 19
  20. 20. Direct Installation Amity School of Business• Abrupt• “Cold turkey” Advantage• Low cost• High interest in making installation a success.• May be the only possible approach if new and existing systems cannot coexist in some form. 20
  21. 21. Direct Installation Amity School of Business
  22. 22. Direct Installation-Risks Amity School of Business• Operational error have direct impact on users and organization.• It may take too long to restore old system, if necessary.• Time-consuming and benefits may be delayed until whole system is installed. 22
  23. 23. Parallel Installation Amity School of Business• Old and new system coexist.• Safe Advantage• New system can be checked against old systems.• Impact of operational errors are minimized because old system is also processing all data. 23
  24. 24. Parallel Installation Amity School of Business
  25. 25. Parallel-Risks Amity School of Business• Not all aspects of new system can be compared to old system.• Very expensive due to duplication of effort to run and maintain two systems.• Can be confusing to users.• May be delay until benefits result.• May not be feasible due to costs or system size. 25
  26. 26. Single Location Install Amity School of Business• Pilot approach.• Middle-of-the road approach• May involve series of single location installations.• Each location may be branch office, factory or department. 26
  27. 27. Single Location Installation Amity School of Business
  28. 28. Advantage-Single Location Amity School of Business• Learning can occur and problems fixed by concentrating on one site.• Limits potential harm and costs from system errors or failure to selected pilot sites.• Can use early success to convince others to convert to new system. 28
  29. 29. Single Location-Risks Amity School of Business• Burden on IS staff to maintain old and new systems.• If different sites require data sharing, extra programs need to be written to “bridge” the two systems.• Some parts of organization get benefits earlier than other parts. 29
  30. 30. Phased Installation Amity School of Business• Staged, incremental, gradual, based on system functional components.• Similar to bringing system out via multiple releases. 30
  31. 31. Phased Installation Amity School of Business
  32. 32. Advantage-Phased Amity School of Business• Allows for system development also to be phased.• Limits potential harm and costs from system error or failure to certain business activities/functions.• Risk spread over time.• Some benefits can be achieved early.• Each phase is small and more manageable. 32
  33. 33. Disadvantage-Phased Amity School of Business• Old and new systems must be able to work together and share data, which likely will require extra programming to “bridge” the two systems.• Conversion is constant and may extend over a long period, causing frustration and confusion for users. 33
  34. 34. Documentation Amity School of BusinessTwo Audiences for the Final Documentation IS Personnel Users
  35. 35. System Documentation Amity School of Business• Detailed information about a system’s design specifications, its internal workings, and its functionality.• System Documentation is further divided into internal, external.
  36. 36. Internal Documentation Amity School of Business• It is a part of program source code. 36
  37. 37. External Documentation Amity School of Business• It includes the outcome of all of the structured diagramming techniques such as DFD, ER Diagram. 37
  38. 38. User Documentation Amity School of Business• Written or visual information about an application system, how it works, and how to use it.
  39. 39. Amity School of Business• System Documentation is intended primarily for maintenance programmers, user documentation is intended mainly for users. 39
  40. 40. Amity School of Business What Makes Good Documentation?• Contains an overview, index, getting started instructions, I.e. – very structured• Describes functionalities• Contains task-based documentation – “How to’s…” – Frequently Asked Questions – Messages & their meanings
  41. 41. Training the end-users Amity School of Business• Training and support help people adequately use computer systems to do their primary work.• Without proper training and the opportunity to ask questions and gain assistance/consultation when needed, users will misuse, underuse, or not use the information system that has been developed.
  42. 42. Training the end-users Amity School of Business• The term training refers to the acquisition of knowledge, skills, and competencies as a result of the teaching of practical skills and knowledge that relate to specific useful competencies.• Support is providing ongoing educational and problem solving assistance to information users. 42
  43. 43. Training Methodologies Amity School of Business• Resident Expert• Computer based instruction• Formal courses-several people taught at the same time.• Software help components.• Tutorials-one person taught at a time.• Interactive training manuals-combinations of tutorials and computer aided instruction• External sources, such as vendor.
  44. 44. Supporting the End-user Amity School of Business• Automated Issue Tracking• Automating support• Providing support through a Help Desk• Other things to consider: – Providing recovery and backup – Disaster recovery – PC maintenance
  45. 45. Why Implementation sometimes Amity School of Business FAIL?Two conditions are necessary for asuccessful implementation effort:•Management support of the system•Involvement of users in the developmentprocess.Despite the support and active participationof users and management, informationsystems implementation still sometimesfails. 45
  46. 46. Insight for Successful Implementation process Amity School of Business• Risk• Commitment to project• Commitment to change• Extension of project definition and planning• Realistic user expectation 46
  47. 47. Amity School of BusinessTwo most common and trusted ways ofdetermining system implementationsuccess are:•The extent to which the system is used andthe user’s satisfaction with the system.•Political Factors should be well addressed. 47
  48. 48. Amity School of Business What is System Maintenance?• Software maintenance is a very broad activity that includes error corrections, enhancements of capabilities, deletion of obsolete capabilities, and optimization.• So, any work done to change the software after it is operational is considered to be a maintenance work.• The purpose of maintenance is to preserve the value of software over time. 48
  49. 49. Amity School of Business• System maintenance is a very important activity of software life cycle which may span for more than 20 years and constitute the highest cost incurred in SDLC.• Maintenance accounts for 50-80% of total system development as shown in following figure. 49
  50. 50. Amity School of Business Code 20%DevelopmentCost Design Test 40% 40% Code Design 8% TestTotal life cycle 11% 11%of software Maintenance 70% 50
  51. 51. Primary activities of Maintenance Amity School of Business Request for system service 1 System and Request program program & documentation Submit test system doc results for user approval Specify Modification required Return requirements modification modified documentation Make required to library changes to programs & Project Notify user Completion systems of project notice completion Test changes 1
  52. 52. Types of Maintenance Amity School of BusinessThree types of maintenance are:• Corrective Maintenance• Adaptive Maintenance• Perfective Maintenance 52
  53. 53. Corrective Maintenance of Business Amity School• It means repairing processing or performance failures or making changes because of previously uncorrected problems or false assumptions.• Corrective maintenance is initiated by the defect in the system.• The defect can result from design errors, logic errors, coding errors, performance or processing failure.
  54. 54. Adaptive Maintenance Amity School of Business• It includes modifying the software to match the changes in the ever changing environment.• The term environment includes totality of all conditions and influences which act from outside upon the software, for e.g., business rules, government policies, work pattern, software and hardware operating platforms.• A change in the whole or part of the environment will require a corresponding modification of the software.
  55. 55. Perfective Maintenance School of Business AmityIt involves making enhancements to improveprocessing performance, interface usability, or to adddesired, but not necessarily required, system features.It means enhancing the performance or modifying theprograms to respond to the user’s additional orchanging needs. Of these types, more time and moneyare spent on perfective than corrective and adaptivemaintenance together.Perfective maintenance refers to enhancements makingthe product better, faster, smaller, better documented,cleaner structured, with more functions and reports.
  56. 56. Amity School of Business Adaptive 25% Perfective 50% Corrective 25%Fig: Distribution of Maintenance Efforts 56
  57. 57. Measuring Maintenance Amity School of Business Effectiveness• Because maintenance can be costly, it is important to measure its effectiveness which is measured in terms of following factors:• No. of failures• Time between failures• Type of failure 57
  58. 58. System Maintenance Vs Amity School of Business Enhancement• If the changes are made in existing functionalities of a system, after it is operational ,then these changes are categorized as system maintenance.• However when new functionality is added onto a existing system then this activity is termed as system enhancement.
  59. 59. Quality Assurance Amity School of Business• It is to certify that the program or software package is current and confirms to standards.• With a growing trend toward purchasing ready to use software, certification has become more important.• A package that is certified goes through a team of specialists who test, review, and determine how well it meets the vendor’s claims. 59
  60. 60. Amity School of BusinessThank you 60