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Unit 10 Implementation and Operation

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Page 1: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

Unit 10

Implementation and Operation

Page 2: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

Key ConceptsImplementation deliverablesDocumentationCodingReuseTestingInstallationTrainingSupportFactors for successMaintenance

Page 3: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors
Page 4: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

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

Page 5: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

ReuseThe 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.

Page 6: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

Approaches to ReuseAd hoc – individual, unplanned

reuse

Facilitated – reuse 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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Page 7: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors
Page 8: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

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

Page 9: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

Categorization of Test Types Tests can be manual or automated, and may or

may not involve code execution.

Without code executionManual – inspectionsAutomated – syntax checking

With code executionManual – walkthroughs and desk-checkingAutomated – unit, integration, system, and stub

testing

Page 10: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

Tests Without Program ExecutionInspections (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 Execution

Desk checkingtrace through the logic of the code,

identifying possible logical errors

WalkthroughsLike desk-checking, but in a group-oriented,

more structured process

Page 12: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

Code walkthrough is one of many types of structured walkthroughs.

Page 13: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

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

Page 14: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

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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Acceptance TestingThe process whereby actual users test a

completed information system, ending with user acceptance of the system

Two phasesAlpha testing – user testing of a completed

information system using simulated dataBeta testing – user testing of a completed

information system using real data in the real user environment

Page 16: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

Specific Elements of Alpha TestingRecovery 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

Page 17: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

Installation OverviewInstallation is organizational process of turning over

from the old information system to the new oneKey concerns include:

Conversion of old data to new systemPotential of system downtime during installationAbility to rollback if problems occurTraining users to new the new system before

installationAvailable support for users of the new systemPossible requirement to run old and new systems side-

by-side How to keep data synchronized between new and old systems

Thorough testing of installation procedures before live deployment

Page 18: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

Installation TypesTypes:

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

Page 19: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

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

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

Phased – Incremental, supports phased system development, minimizes error impact, difficult to coordinate old and new components

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Page 22: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

Types of DocumentationSystem – 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.

Page 23: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

Types of System DocumentationInternal – 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 more information.

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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

Page 26: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

Possible Topics for Training

Use of the systemGeneral computer conceptsInformaiton systems conceptsOrganizational conceptsSystem managementSystem installation

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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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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.

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Automated Support

Manual support is often too labor-intensive, so when possible automated approaches are used

Common methods:Online support forumsBulletin board systemsOn-demand faxVoice-response systems

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Help Desks and Information CentersHelp 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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Critical Success Factors for Implementation Success

Risk management

Commitment to project

Commitment to change

Extent of project definition and planning

Realistic user expectations

Page 33: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

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

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Maintaining Information Systems Four major activities:

1. Obtaining maintenance requests2. Transforming requests into changes3. Designing changes4. Implementing changes

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

Page 36: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

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

enhance its functionality

Page 37: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

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

Page 38: Unit 10 Implementation and Operation. Key Concepts Implementation deliverables Documentation Coding Reuse Testing Installation Training Support Factors

Measures of Maintenance Effectiveness

Number of failures

Mean time between failures (MTBF)

Type of failure

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Maintenance requests can be frequent.

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