(Week 13) Software Quality Management

ISO

International Standard Organization

Quality Model Characteristics

• Functionality

• Reliability

• Usability

• Efficiency

• Maintainability

• Portability

QM Characteristic: Functionality

Capability of software product to provide functions which meet stated and implied needs

Sub-Characteristics:

• Suitability: appropriate allocated to allow for tasks to further completion

• Accuracy: precision

• Interoperability: Capability of the software product to interact with one or more specified system

• Security: Protect info from unauthorized personal

• Compliance: Adherence to standards, conventions, regulations, etc..

QM Characteristic: Reliability

Capability of software product to maintain a specified level of performance

Sub-Characteristics:

• Maturity: Capability of software to with stand faults(note: result of human error)

• Recoverability: Ability for product to bounce back to specified level performance and recover data affected by failure

QM Characteristic: Usability

Capability of software product to be understood, learned, used and attractive to user

Sub-Characteristics:

• Understandability: Capability of software product to enable the user to understand whether the software is suitable and how it can be used in certain scenario /instances

  • Does it fit needs?

• Learnability: Capability of the software product to enable the user to learn its application

  • Is it easy to learn how to use to suffice the needs?

• Operability: Capability of the software product to enable the user to operate and control it

  • Can the user control it easily

• Attractiveness:

  • Attracting the users attention

• Compliance:

  • Being able to adhere to specified requirements regarding usability

QM Characteristic: Efficiency

Capability of Software product to provide appropriate performance, relative to the amount of resources used (resources used to performance ration)

Sub-Characteristics:

• Time Behavior:

  • Speed of application

• Resource Utilization:

  • Appropriate use of resources(optimally)

• Compliance:

  • Adherence to standards regarding efficiency

Maintainability

Capability of software product to be modified

Sub-Characteristics:

• Analyzability:

  • Easily diagnosable

• Changeability:

  • Enable modification to be implemented

• Stability

  • Capability of the software product to avoid unexpected effects from modifications of the software

• Testability:

  • Capability of the software product to enable modified software to be validated

QM Characteristic: Portability

Capability of software product to be transferred from one environment to another

Sub-Characteristics:

• Adaptability:

  • Capability of software product to be adapted for different specified environments without applying actions or means other than those provided for this purpose for the software considered

• Install-ability

  • Capability of the software product to be installed in a specified environment

• Co-Existance:

  • Capability of the software product to co-exist with other independent software in a common environment sharing common resources

• Replicability:

  • Capability of the software product to be used in another specified software product for the same purpose in the same environment

• Compliance:

  • Compliant to standards within the region of portability

Software Quality Assurance

Degree of conformance to explicitly stated functional and performance requirements, explicitly documented development standards, and implicit characteristics that are expected of all professionally developed software

Three Emphases

• Requirements are the foundation from which quality is measured

• Developers should follow the specified standards for development

• Software must conform to its implicit requirements as well.

Software Engineers

Software engineers who do technical work address quality by applying solid technical methods and measures, conducting formal technical reviews and testing

SQA(software quality assurance) Group

• Responsible for QA planning, oversight, record keeping, analysis and reporting.

• It assists developers in achieving a high quality end product

Roles of SQA Group

• Prepare a SQA plan for a project

• Participate in the development of process description

• Review SE Activities to verify compliance with the defined software process

• Audits designated software work products to verify compliance with those defined as part of the process

• Ensures that deviations in work and work products are documented and handled.

• Records any non-compliance and reports to senior management

Software Reviews

• Reviews are a “filter" for software engineering process.

• Applied at various points during software development and serve to uncover errors.

• To purify the work products that occur at analysis, design, and coding

Defect(Fault)

Quality problem that is discovered after release

Error

Quality problem that is discovered by engineers before release

Formal Technical Review(FTR)

is a SQA activity performed by software engineers:

• Objectives:

  • To cover errors in function, logic or implementation

  • To verify that the software under review meets its requirements

  • To ensure that the software has been represented according to predefined standards

  • To achieve software that is developed in a uniform manner

  • To make projects more manageable

FTR Meeting

Each FTR is conducted as a meeting:

• Constraints:

• 3-5 people involved

• advance preparation should occur (no more than 2 hours)

• Duration of the meting should be less than 2 hours

Procedure for FTR Meeting

• The producer informs the project leader that work product is complete and that a review is required

• The project leader contacts the review leader

• The review leader does a brief review and distributes material to 2-3 viewers

• The Reviewers review the work and make note

• First: begins with agenda and brief introduction

• Producer proceeds to “walk through” the work product

• Reviewers may raise issues based on their advance preparation

• When valid problems or errors are discovered the recorder notes each

• At the end of the meeting, all attendees must decide whether to:

  • Accept: product without further modification

  • Reject: the work product due to severe errors

  • Accept: the work product provisionally

Guidelines for FTR(formal technical review) meeting

• Review the product, not the producer

• Set an agenda and maintain it

• Limit debate and rebuttal

• Enunciate problem areas, but don’t attempt to solve every problem noted

• Take written notes

• Limit the number of participants and insist upon advance preparation

Statistical Quality Assurance(Quantitative data)

Approach that is preferred for understanding quality