14-1 © Prentice Hall, 2007 Chapter 14: OOSAD Implementation and Operation Object-Oriented Systems...

14-1 © Prentice Hall, 2007

Chapter 14:Chapter 14:OOSAD Implementation and OOSAD Implementation and

OperationOperation

Object-Oriented Systems Analysis and Design

Joey F. George, Dinesh Batra,

Joseph S. Valacich, Jeffrey A. Hoffer

14-2Chapter 14 © Prentice Hall, 2007

Chapter ObjectivesChapter Objectives

After 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.


Chapter Objectives Chapter Objectives (Continued)(Continued)

After 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.


Chapter Objectives Chapter Objectives (Continued)(Continued)

After 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.


Maintaining Information SystemsMaintaining Information Systems

Four major activities:

1. Obtaining maintenance requests

2. Transforming requests into changes

3. Designing changes

4. Implementing changs


Maintenance is a subset of the activities of the entire development process.


What Is Coding?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


ReuseReuse

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.


Approaches to ReuseApproaches 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

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What Is Software Application What Is Software Application Testing?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


Categorization of Test TypesCategorization 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


Tests Without Program ExecutionTests 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


Manual Tests With Program Manual Tests With Program ExecutionExecution

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


Code walkthrough is one of many types of structured walkthroughs.


Automated Tests With Program Automated Tests With Program ExecutionExecution

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


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


Acceptance TestingAcceptance TestingThe 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


Specific Elements of Alpha TestingSpecific 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


What Is Installation?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


Direct – cold turkey, low cost, greater impact of errors

Parallel – old and new coexist, minimize error impact, high cost in system resources


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


Types of DocumentationTypes 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.


Types of System DocumentationTypes 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.


User documentation is often in the form of online help…

… sometimes with Web connections for further information.


What Is Training and Support?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


Possible Topics for TrainingPossible Topics for Training

Use of the systemGeneral computer conceptsInformaiton systems conceptsOrganizational conceptsSystem managementSystem installation


Training methods can be interpersonal, manual, or automated.


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.


What is System Support?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.


Automated SupportAutomated 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


Help Desks and Information Help Desks and Information CentersCenters

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


Critical Success Factors for Critical Success Factors for Implementation SuccessImplementation Success

Risk management

Commitment to project

Commitment to change

Extent of project definition and planning

Realistic user expectations


Critical Success Factors for Critical Success Factors for Implementation Success (cont.)Implementation Success (cont.)

Relevance of system for users’ work

Ease of use

User demographics (e.g. computer savvy)

Support of user creativity

User satisfaction


What Is System Maintenance?What Is System Maintenance? Changes made to a system to fix or enhance its

functionality


Maintenance Cost FactorsMaintenance Cost Factors

Latent defectsNumber of customers for the systemQuality of system documentationQuality of maintenance personnelAvailability of automated toolsQuality of program code and system design


Measures of Maintenance Measures of Maintenance EffectivenessEffectiveness

Number of failures

Mean time between failures (MTBF)

Type of failure


Maintenance requests can be frequent.

Priorities among requests should be made based on the type and urgency of the request.


RecapRecapAfter 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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