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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

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Chapter ObjectivesChapter Objectives– Describe the process of coding, testing, and converting an organizational

information system.– Apply four installation strategies: direct, parallel, single-location, and

phased.– 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.– Explain why systems implementation sometimes fails.– Explain and contrast four types of maintenance.– Describe factors that influence system maintenance costs.

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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

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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.

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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

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

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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

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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

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Code walkthrough is one of many types of structured walkthroughs.

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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

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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

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

the old information system to the new one

Types:– Direct– Parallel– Single location– Phased

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

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

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Single Location – Pilot approach, allows learning and minimizes error impact, lower resource demand than parallel, difficult to coordinate and maintain

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

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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.

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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.

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User documentation is often in the form of online help, sometimes with Web connections for further information.

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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

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Training methods can be interpersonal, manual, or automated.

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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.

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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

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What Is System Maintenance?What Is System Maintenance?

Changes made to a system to fix or enhance its functionality

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System maintenance operates as repeated, miniaturized systems development cycles.

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Maintenance Cost FactorsMaintenance 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

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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.