ISO/IEC 9126 in Software Engineering
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 :
Part-1 Software Engineering – Product Quality “Quality model” :
It describes 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 Metrices” :
It’s use is to describes external metrices that are used to measure characteristics and sub-characteristics which are identifies in part 1.
Part-3 Software Engineering – Product Quality “Internal Metrices” :
It’s use is to describes internal metrices that are used to measure characteristics and sub-characteristics which are identifies in part 1.
Part-4 Software Engineering – Product Quality “Quality in use metrices” :
It’s use is to identify metrices which are used to measure effects of combined quality characteristics for user.
As from above discussion, it is concluded that first three parts are concerned with describing and measuring quality of software product and fourth part concerned about quality of software product from user point of view.
Furthermore, first part i.e. Quality model is concerned classified into two categories as depicted in the following figure :
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 characteristics is subdivided into related sub-characteristics which are also depicted in the above example.
- Functionality: The functions are those that will satisfy implied needs.
- Functionality Compliance
- Reliability: A set of attributes that will bear on the capability of software to maintain the level of performance.
- Fault Tolerance
- Reliability Compliance
- Usability: A set of attributes that bear on the effort needed for use by a implied set of users.
- Learn ability
- 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.
- Maintainability Compliance
- Portability: A set of attributes that bear on the ability of software to be transferred from one environment to another.
- Replace ability
- Portability Compliance
Quality in use Model : It identifies the four quality characteristics i.e. Effectiveness, Productivity, Safety, Satisfaction.