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Product Quality and

Process Quality

By:By: AdnanAdnan KhanKhan

Software Quality Assurance

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SQA 210/4/2009

Product Quality The quality of the end product depends upon:

The attributes and characteristics of the software

product The degree that they fulfill specific project needs

To ensure that the product meets a definedquality standard: Standards and practices for s/w product must be

defined early in the development process

Standards must be specific to software product

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SQA 310/4/2009

Software Attributes Reliability

Usability

Functionality

Maintainability

Correctness

Portability

Testability Efficiency

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SQA 410/4/2009

Attributes are specific to S/Ware

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SQA 510/4/2009

Classification of Software Quality

Attributes

Performance Attributes

Form Attributes

Processing Attributes

Functional Attributes

Operational Integrity Attributes

Maintainability Attributes

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SQA 610/4/2009

Software Product Quality

Models

McCalls & Boehms S/W Product Quality

Model

The ISO 9126 Standard Quality Model

Others like Goal Question Metric.

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SQA 810/4/2009

McCalls Product Quality Model

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SQA9

10/4/2009

McCalls Product Quality Model

oAccuracy

oError Tolerance

oConsistency

oSimplicity

Reliability

oTraceability

oCompletenessoConsistency

Correctness

oStorage Requirement

oExecution Speed

Efficiency

oAccess Control

oAccess Audit

Integrity

oOperability

oTraining

oCommunicativeness

oI/O VolumeoI/O Rate

UsabilityProduct

Operation

CriteriaFactorUse

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SQA10

10/4/2009

oExpandability

oArchitecture Usability

oSelf descriptiveness

oModularity

Flexibility

oSimplicity

oScope for Automation

Testability

oConsistency

oSimplicity

oConciseness

o

Self-descriptivenessoModularity

MaintainabilityProduct Revision

McCalls Product Quality Model

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SQA11

10/4/2009

oModularity

oCommunications commonality

oData commonality

Inter-operability

oSelf Descriptiveness

oModularity

oMachine Independence

oOS Independence

Portability

oArchitectural Usability

oSelf Descriptiveness

oModularity

oMachine Independence

o

Operating system Independence

Re-usabilityProduct

Transition

McCalls Product Quality Model

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SQA12

10/4/2009

ISO 9126 Standard Quality

Model The objective of this standard is to provide a

framework for the evaluation of software quality.

ISO/IEC 9126 does not provide requirements forsoftware, but it defines a quality model which isapplicable to every kind of software.

It defines six product quality characteristics and

in an annex provides a suggestion of quality subcharacteristics.

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SQA13

10/4/2009

ISO 9126 Standard Quality

Model

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Process Quality

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SQA15

10/4/2009

ISO 8402 Quality Definition

Quality is the totality of features

and characteristics of aproduct or service that bear on

its ability to satisfy stated or

implied needs

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SQA16

10/4/2009

Process Quality

A Quality Process is the one that leads to theproduction of high Quality Product

Quality Process = Quality Product

To evaluate the process it has to be madetangible.

One way of doing this is to base the process ona standard or model against which conformancemay be assessed

The process evaluation only take account of andis ultimately only as good as, the underlyingmodel or standard used

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SQA17

10/4/2009

Process Quality (Cont.)

A Process Approach implies that every activityin an organization has a defined start and finishand can be measured.

A software product should meet its definedquality standardsTo ensure that the product meets a defined

quality standard:

Standards and practices for s/w product must bedefined early in the development process

Standards must be specific to software product

Quality gates must be identified to monitor itsquality

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SQA18

10/4/2009

Standards Defined Standards are mandatory requirements

employed and enforced to prescribe a

disciplined uniform approach to softwaredevelopment, that is mandatory

conventions and practices are in fact

standards. IEEE STD 983-1986

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SQA19

10/4/2009

Quality Standards and Models In Europe and wider world, the prevalent

approach is to base the process or any

evaluation of it on a Standard. e.g ISO9000 series

In US, the focus for process Quality

Improvement and Evaluation is ProcessMaturity Model.

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SQA20

10/4/2009

Some Common Standards/Models CMMi for an integrated software process

ISO 9001 for process mapping

Six-Sigma initiative for continuousimprovement on existing processes

PCMM for people involvement in quality

initiatives

SPiCE Software Process Improvement

and Capability dEtermination

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SQA21

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References Software Quality Assurance Principles and

Practice by Nina S Godbole

Chapter 4 4.3 (4.3.1, 4.3.2)

4.4 (4.4.1, 4.4.2, 4.4.3)

4.5 (4.5.1, 4.5.2)

Software Engineering by Pressman,

Chapter 15 15.1.1

15.1.2