14-1 © prentice hall, 2004 chapter 14: oosad implementation and operation object-oriented systems...

14-1 © Prentice Hall, 2004

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, 2004

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.


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

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 (Developers do not

receive incentives, developers keep track of their own s/w assets)

Facilitated – use informally managed and disseminated by expert guru evangelists (Developers are encouraged to reuse by a promoter, some special tools/techniques)

Managed – organizationally enforced reuse policies and practices (Reuse is practiced and results measured. Sources from utility asset libraries, companies that sell assets, Open Source community)

Designed – reusable components developed and maintained in-house (Focus on developing reusable assets inhouse rather than buying/finding.)

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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


Tests can be manual or automated, and may or may not involve code execution.


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 (paper and pencil)

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 for internal consistency

Integration tests – testing all modules and components of the application together for interaction compatibilities

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


What Is Installation?What Is Installation? The organizational process of turning over

from the old information system to the new Types:

Direct Parallel Single location Phased


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 – Staged and incremental, supports phased system development, minimize error impact, difficult to coordinate old components 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


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.


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


Project Close-DownProject Close-Down

Evaluate team members and reassign Notify affected parties that project has

ended and is in operation mode Conduct post-project reviews with

management and customers Close out customer contract – get sign-off System audit


What Is System Maintenance?What Is System Maintenance?

Changes made to a system to fix or enhance its functionality


System maintenance operates as repeated, miniaturized systems development cycles.


Maintenance requests can be frequent.

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


Maintenance Cost FactorsMaintenance Cost Factors

Latent defects (Unknown errors after install)

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


RecapRecap 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.


Any Questions?

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