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14-1 © Prentice Hall, 2007 Chapter 14: OOSAD Implementation and Operation Object-Oriented Systems Analysis and Design Joey F. George, Dinesh Batra, Joseph.

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Presentation on theme: "14-1 © Prentice Hall, 2007 Chapter 14: OOSAD Implementation and Operation Object-Oriented Systems Analysis and Design Joey F. George, Dinesh Batra, Joseph."— Presentation transcript:

1 14-1 © Prentice Hall, 2007 Chapter 14: OOSAD Implementation and Operation Object-Oriented Systems Analysis and Design Joey F. George, Dinesh Batra, Joseph S. Valacich, Jeffrey A. Hoffer

2 Chapter © Prentice Hall, 2007 Chapter Objectives Af ter studying this chapter you should be able to: – Describe the process of coding, testing, and converting an organizational information system. – Apply four installation strategies: direct, parallel, single-location, and phased.

3 Chapter © Prentice Hall, 2007 Chapter Objectives (Continued) Af ter studying this chapter you should be able to: – List the deliverables for documenting the system and providing user training and support. – Compare various training modes. – Discuss the issues of providing support to end users.

4 Chapter © Prentice Hall, 2007 Chapter Objectives (Continued) Af ter studying this chapter you should be able to: – Explain why systems implementation sometimes fails. – Explain and contrast four types of maintenance. – Describe factors that influence system maintenance costs.

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8 Chapter © Prentice Hall, 2007 Maintaining Information Systems Four major activities: 1. Obtaining maintenance requests 2. Transforming requests into changes 3. Designing changes 4. Implementing changs

9 Chapter © Prentice Hall, 2007 Maintenance is a subset of the activities of the entire development process.

10 Chapter © Prentice Hall, 2007 What Is Coding? Translation of physical design specifications into working computer code Coding involves use of programming languages such as Java or Visual Basic Coding often involves reuse and/or modification of existing components and objects eXtreme programming – an intensive coding and testing approach involving two-person teams and customer involvement

11 Chapter © Prentice Hall, 2007 Reuse The use of previously written software resources, especially objects and components, in new applications Results in great savings of system development time Object-oriented systems are very conducive to reuse.

12 Chapter © Prentice Hall, 2007 Approaches to Reuse Ad hoc – individual, unplanned use Facilitated – use informally managed and disseminated by expert guru evangelists Managed – organizationally enforced reuse policies and practices Designed – reusable components developed and maintained in-house Cost and commitment low high

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14 Chapter © Prentice Hall, 2007 What Is Software Application Testing? Manual and automated procedures for validating correctness of program code, including syntactical and execution issues Testing Syntax – grammatical rules applied to programming languages Testing Execution – logic and performance of the software during operation

15 Chapter © Prentice Hall, 2007 Categorization of Test Types Tests can be manual or automated, and may or may not involve code execution. Without code execution – Manual – inspections – Automated – syntax checking With code execution – Manual – walkthroughs and desk-checking – Automated – unit, integration, system, and stub testing

16 Chapter © Prentice Hall, 2007 Tests Without Program Execution Inspections (manual) – Participants examine program code for predictable, language-specific errors Syntax checking (automated) – Compiler or interpreter tests source code for grammatical errors while translating to executable format

17 Chapter © Prentice Hall, 2007 Manual Tests With Program Execution Desk checking – trace through the logic of the code, identifying possible logical errors Walkthroughs – Like desk-checking, but in a group-oriented, more structured process

18 Chapter © Prentice Hall, 2007 Code walkthrough is one of many types of structured walkthroughs.

19 Chapter © Prentice Hall, 2007 Automated Tests With Program Execution Unit tests – a module tested in isolation to discover any errors in its code Integration tests – bringing together all objects and components that a program comprises for testing purposes System tests – testing all programs and applications together to ensure performance and reliability Acceptance tests – user-satisfaction tests

20 Chapter © Prentice Hall, 2007 A test case is a specific scenario of transactions, queries, or navigation paths that represent a typical, abnormal, or critical use of the system. Allows repeated testing with each application change

21 Chapter © Prentice Hall, 2007 Acceptance Testing The process whereby actual users test a completed information system, ending with user acceptance of the system Two phases – Alpha testing – user testing of a completed information system using simulated data – Beta testing – user testing of a completed information system using real data in the real user environment

22 Chapter © Prentice Hall, 2007 Specific Elements of Alpha Testing Recovery testing – force the software or environment to fail to verify if recovery is performed correctly Security testing – verify that protection mechanisms correctly prevent improper penetration Stress testing – try to break the system (e.g. incomplete database records or overloaded transaction volume) Performance testing – test in a variety of platforms to ensure consistent response times and performance

23 Chapter © Prentice Hall, 2007 What Is Installation? The organizational process of turning over from the old information system to the new one Types: – Direct installation – changing from old to new system by turning off the old system when the new one is turned on – Parallel installation – running old and new systems at the same time until management decides to turn off the old one – Single location installation – trying the new system at one site before deciding to adopt it across the organization – Phased installation – incrementally changing from the old system to the new system by gradually converting functional components

24 Chapter © Prentice Hall, 2007 Direct – cold turkey, low cost, greater impact of errors Parallel – old and new coexist, minimize error impact, high cost in system resources

25 Chapter © Prentice Hall, 2007 Single Location – Pilot approach, allows learning and minimizes error impact, lower resource demand than parallel, difficult to coordinate and maintain Phased – Incremental, supports phased system devt., minimize error impact, difficult to coordinate old and new components

26 Chapter © Prentice Hall, 2007 Types of Documentation System – detailed information about a system’s design specifications, its inner workings, and its functionality User – written or other visual information about an application system, how it works, and how to use it.

27 Chapter © Prentice Hall, 2007 Types of System Documentation Internal – comments in source code, generated during the coding process or automatically by software compilers or documenters External – outcomes of all structured diagrams, including use cases, design classes, activity and sequence diagrams, etc.

28 Chapter © Prentice Hall, 2007 User documentation is often in the form of online help… … sometimes with Web connections for further information.

29 Chapter © Prentice Hall, 2007 What Is Training and Support? Providing on-going educational and problem-solving assistance to information systems users Training and support material and jobs must be designed along with the associated information systems

30 Chapter © Prentice Hall, 2007 Possible Topics for Training Use of the system General computer concepts Informaiton systems concepts Organizational concepts System management System installation

31 Chapter © Prentice Hall, 2007 Training methods can be interpersonal, manual, or automated.

32 Chapter © Prentice Hall, 2007 Electronic Performance Support Systems (EPSS), like Microsoft Office Assistant, are components of software applications that embed training and information for the user, in the form of tutorials, expert systems, and hyperlink jumps to reference topics.

33 Chapter © Prentice Hall, 2007 What is System Support? Providing ongoing education and problem solving assistance to information systems users. Support materials and jobs must be designed along with the associated information system.

34 Chapter © Prentice Hall, 2007 Automated Support Manual support is often too labor-intensive, so when possible automated approaches are used Common methods: – Online support forums – Bulletin board systems – On-demand fax – Voice-response systems

35 Chapter © Prentice Hall, 2007 Help Desks and Information Centers Help desk – a single point of contact for all user inquiries and problems about a particular information system or for all users in a particular department Information center – an organizational unit whose mission is to support users in exploiting information technology

36 Chapter © Prentice Hall, 2007 Critical Success Factors for Implementation Success Risk management Commitment to project Commitment to change Extent of project definition and planning Realistic user expectations

37 Chapter © Prentice Hall, 2007 Critical Success Factors for Implementation Success (cont.) Relevance of system for users’ work Ease of use User demographics (e.g. computer savvy) Support of user creativity User satisfaction

38 Chapter © Prentice Hall, 2007 What Is System Maintenance? Changes made to a system to fix or enhance its functionality

39 Chapter © Prentice Hall, 2007 Maintenance Cost Factors Latent defects Number of customers for the system Quality of system documentation Quality of maintenance personnel Availability of automated tools Quality of program code and system design

40 Chapter © Prentice Hall, 2007 Measures of Maintenance Effectiveness Number of failures Mean time between failures (MTBF) Type of failure

41 Chapter © Prentice Hall, 2007 Maintenance requests can be frequent. Priorities among requests should be made based on the type and urgency of the request.

42 Chapter © Prentice Hall, 2007 Recap After studying this chapter we learned to: – Describe coding, testing, and converting. – Apply four installation strategies. – Generate system and user documentation. – Compare training modes. – Discuss techniques of user support. – Discuss maintenance types. – Discuss maintenance cost factors.


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