Software Quality Part 3: Quality Attributes & Models

Questions and Answers

What is flexibility in the context of software quality?

The effort required to test a program to ensure that it performs its intended function

The extent to which a program satisfies its specification and fulfills the customer’s mission objectives

The effort required to modify an operational program (correct)

The extent to which a program can be expected to perform its intended function with required precision under stated conditions for a stated period of time

Which of the following is NOT a characteristic of product transition in McCall’s Software Quality Model?

Interoperability

Reusability

Correctness (correct)

Portability

What is the primary concern of the efficiency characteristic in software quality?

Meeting the customer’s mission objectives

Maximizing the performance of the software

Ensuring the software is free from design defects

Minimizing the consumption of computing resources (correct)

What is the main goal of testability in software quality?

To generate useful messages for testing and debugging purposes Signup and view all the answers

What is interoperability in the context of software quality?

The effort required to couple one system to another Signup and view all the answers

What is reusability in the context of software quality?

The extent to which a program (or part of a program) can be reused in other applications Signup and view all the answers

What is the primary focus of product operations in McCall’s Software Quality Model?

Using the software to achieve its intended function Signup and view all the answers

What is portability in the context of software quality?

The effort required to transfer the program from one hardware and/or software system environment to another Signup and view all the answers

What is correctness in the context of software quality?

The extent to which a program satisfies its specification and fulfills the customer’s mission objectives Signup and view all the answers

What is reliability in the context of software quality?

The extent to which a program can be expected to perform its intended function with required precision under stated conditions for a stated period of time Signup and view all the answers

Study Notes

Software Quality Attributes

Quality attributes are measurable or observable characteristics of products and processes.
They are used early in the development process to identify user quality requirements.
Each system has specific and unique quality needs, which are a function of the purpose of the application.
Quality attributes can be classified into internal and external quality attributes:
- Internal: Derived immediately from the product or process description.
- External: Derived from the relationship between the environment and the system.

Internal and External Software Quality Attributes

Internal quality concerns the developers/maintainers of the software, making it easy to change, add new features, and test.
External quality concerns the users of the software, measuring how the system meets the requirements of its stakeholders.
- Examples of internal quality attributes: Maintainability, Flexibility, Portability, Reusability, Readability, Testability, Understandability.
- Examples of external quality attributes: Correctness, Usability, Efficiency, Reliability, Integrity, Adaptability, Accuracy, Robustness.

Definitions and Measures of Some Software Quality Attributes

Maintainability: Easy to change and adapt to new requirements, measured in terms of change logs and impact analysis.
Correctness: Lack of bugs and defects, measured in terms of defect rate.
Usability: Sufficiently convenient for the intended users, measured in terms of user satisfaction.
Reliability: Does not fail or crash often, measured in terms of failure rate.
Capability: Does all that is required, measured in terms of requirements coverage.
Performance: Fast and small enough, measured in terms of speed and space usage.
Installability: Convenient and fast to install, measured in terms of user satisfaction.
Documentation: Well-documented, measured in terms of user satisfaction.
Availability: Easy to access and available when needed, measured in terms of user satisfaction.

Software Quality Models

A quality model is a set of selected quality characteristics (attributes) and sub-characteristics together with the assigned measures.
The quality model provides the basis for specifying quality requirements and evaluating quality.
Well-known software quality models include: McCall Model, Boehm Model, FURPS Model, Dromey Model, and ISO/IEC 9126 Model.

McCall Software Quality Model

Classifies 11 quality factors (attributes) into three categories: Product Revision, Product Transition, and Product Operations.
Product Revision factors:
- Maintainability
- Flexibility
- Testability
Product Transition factors:
- Portability
- Reusability
- Interoperability
Product Operations factors:
- Correctness
- Reliability
- Efficiency
- Integrity
- Usability

Description

This quiz covers the concepts of software quality attributes and models. It's part of a software quality course, focusing on measurable characteristics of products and processes. Learn about identifying user quality requirements in the development process.