Copyright © Jerzy R. Nawrocki

ISO 9126 and Non-functional Requirements

ISO 9126 and Non-functional Requirements

Jerzy.Nawrocki@put.poznan.plwww.cs.put.poznan.pl/jnawrocki/require

Requirements Engineering & Project Management

Lecture 4

J.Nawrocki, ISO 9126

Introduction

Project Vision

Business Process Descr. / Operational Scenarios

Functional Requirements

Non-functional Requirements

Development, Implem. & Testing

Transition

J.Nawrocki, ISO 9126

Introduction

Project Vision

Business Process Descr. / Operational Scenarios

Functional Requirements

Non-functional Requirements

Development, Implem. & Testing

Transition

ISO 9126

J.Nawrocki, ISO 9126

Introduction

ISO 9126: Software Engineering – Product Quality

Part 1: Quality ModelPart 2: External MetricsPart 3: Internal MetricsPart 4: Quality-in-use Metrics

J.Nawrocki, ISO 9126

Agenda

• Introduction

• Quality Model

• Quality in Use

• Internal and External Quality

J.Nawrocki, ISO 9126

Quality in the lifecycle

Process quality

Internal quality

attributes

External quality

attributes

Qualityin use

attributes

Impacts Impacts Impacts

Development process

Software product Effect of using product

J.Nawrocki, ISO 9126

Quality in the lifecycle

Internal quality

External quality

Qualityin use

Indicates

Software product Effect of using product

Indicates

J.Nawrocki, ISO 9126

External and Internal Quality

Maintainability

Functionality

Reliability

Usability

Efficiency

Portability

External and Internal Quality Characteristics

J.Nawrocki, ISO 9126

Quality-in-use

Effectiveness

Productivity

Safety

Satisfaction

Quality-in-use Characteristics

J.Nawrocki, ISO 9126

Agenda

• Introduction

• Quality Model

• Quality in Use

• Internal and External Quality

J.Nawrocki, ISO 9126

Quality-in-use

Effectiveness

Productivity

Safety

Satisfaction

Quality-in-use Characteristics

J.Nawrocki, ISO 9126

Quality-in-use Metrics

Task effectiveness – What proportion of the goals of the tasks is achieved correctly?

Task completion – What proportion of the tasks is completed (number of tasks completed / total number of tasks attempted)?

Error frequency – What is the frequency of errors?

Effectiveness

J.Nawrocki, ISO 9126

Quality-in-use Metrics

Task time – How long does it take to complete a task?

Task efficiency – How efficient are the users (Task effectiveness / Task time)?

Economic productivity – How cost-effective is the user (Task effectiveness / total cost of the task)?

Productivity

J.Nawrocki, ISO 9126

Quality-in-use Metrics

User health and safety – What is the incidence of health problems among users of the product?

Economic damage – What is the incidence of economic damage?

Safety

J.Nawrocki, ISO 9126

Quality-in-use Metrics

Satisfation scale – How satisfied is the user?

Satisfation questionnaire – How satisfied is the user with specific software features?

Satisfaction

J.Nawrocki, ISO 9126

Agenda

• Introduction

• Quality Model

• Quality in Use

• Internal and External Quality

J.Nawrocki, ISO 9126

External and Internal Quality

Maintainability

Functionality

Reliability

Usability

Efficiency

Portability

External and Internal Quality Characteristics

J.Nawrocki, ISO 9126

Functionality

• Suitability

• Accuracy

• Interoperability

• Security

• Functionality compliance

J.Nawrocki, ISO 9126

Reliability

• Maturity

• Fault tolerance

• Recoverability

• Compliance

J.Nawrocki, ISO 9126

Usability

• Uderstandability

• Learnability

• Operability

• Attractiveness

• Compliance

J.Nawrocki, ISO 9126

Efficiency

• Time behaviour

• Resource utilization

• Compliance

J.Nawrocki, ISO 9126

Maintainability

• Analysability

• Changeability

• Stability

• Tastability

• Compliance

J.Nawrocki, ISO 9126

Portability

• Adaptability

• Installability

• Co-existance

• Replaceability

• Compliance

J.Nawrocki, ISO 9126

Homework

Prepare a spreadsheet that would support collection of non-functional requirements based on ISO 9126.

UsabilityUsability

Understandability H

Learnability H

Operability L

J.Nawrocki, ISO 9126

Summary

•Quality views: Quality-in-use, External & Internal quality•Quality characteristics: 4 + 6•External & Internal subcharacteristics•Quality metrics – Examples