ISO/IEC 9126 is an international standard proposed to make sure ‘quality of all software-intensive products’ which includes a system like safety-critical where in case of failure of software lives will be in jeopardy. ISO i.e. International Organization for Standardization and IEC i.e. International Electrotechnical Commission have developed ISO/IEC 9126 standards for software engineering → Product Quality to provide an all-inclusive specification and evaluation model for the quality of the software product.
The standard is divided into 4 parts as depicted in the following figure:
Parts of Standard
Part-1: Software Engineering: Product Quality “Quality model”: It describes the quality model framework which explains relationships between different approaches to quality as well as identifying quality characteristics and sub-characteristics of software products.
Part-2: Software Engineering: Product Quality “External Metrics”: Its use is to describe external metrics that are used to measure characteristics and sub-characteristics which are identified in part 1.
Part-3: Software Engineering: Product Quality “Internal Metrics”: Its use is to describe internal metrics that are used to measure characteristics and sub-characteristics which are identified in part 1.
Part-4: Software Engineering: Product Quality “Quality in use metrics”: Its use is to identify metrics that are used to measure the effects of combined quality characteristics for users.
From the above discussion, it is concluded that the first three parts are concerned with describing and measuring the quality of software products, and the fourth part is concerned with the quality of software products from the user’s point of view.
Furthermore, the first part i.e. the Quality model is concerned classified into two categories as depicted in the following figure:
Characteristics of Quality Model
Internal External Quality Part
It determines the quality of a software product through six characteristics which are Functionality, Reliability, Usability, Efficiency, Maintainability, and Portability. Each characteristic is subdivided into related sub-characteristics which are also depicted in the above example.
Functionality
The functions are those that will satisfy implied needs.
- Suitability
- Accuracy
- Interoperability
- Security
- Functionality Compliance
Reliability
A set of attributes that will bear on the capability of software to maintain the level of performance.
- Maturity
- Fault Tolerance
- Recoverability
- Reliability Compliance
Usability
A set of attributes that bear on the effort needed for use by an implied set of users.
- Understandability
- Learnability
- Operability
- Attractiveness
- Usability Compliance
Efficiency
A set of attributes that bear on the relationship between the level of performance of the software under stated conditions.
- Time Behavior
- Resource Utilization
- Efficiency Compliance
Maintainability
A set of attributes that bear on the effort needed to make specified modifications.
- Analyzability
- Changeability
- Stability
- Testability
- Maintainability Compliance
Portability
A set of attributes that bear on the ability of software to be transferred from one environment to another.
- Adaptability
- Installability
- Co-existence
- Replaceability
- Portability Compliance
Quality in Use Model
It identifies the four quality characteristics.
- Effectiveness
- Productivity
- Safety
- Satisfaction
Questions For Practice
1. According to the ISO-9126 Standard Quality Model, match the attributes given in List 1 with their definition in List-2. [UGC-NET CS 2019]
|
List-1 |
List-2 |
|---|---|
|
a. Functionality |
i. Relationship between level of performance and amount of resources |
|
b. Reliability |
ii. Characteristics related to the achievement of the purpose |
|
c. Efficiency |
iii. Efforts needed to make for improvement |
|
d. Maintainability |
iv. The capability of software to maintain the performance of Software |
Choose the correct option from the ones given below.
(A) a-i, b-ii, c-iii, d-iv
(B) a-ii, b-i, c-iv, d-iii
(C) a-ii, b-iv, c-i, d-iii
(D) a-i, b-ii, c-iv, d-iii
Solution: Correct Answer is (C).
Frequently Asked Questions
1. What is ISO 9126 used for?
Answer:
ISO 9126 is a type of international software that is used for creating a solid framework for assessing the software.
2. What are the characteristics of quality of ISO 9126?
Answer:
ISO 9126 determines the characteristics of the product via six characteristics that are mentioned below.
- Functionality
- Reliability
- Usability
- Efficiency
- Maintainability
- Portability
