ISO / IEC 9126
The ISO / IEC 9126 standard is one of several models for ensuring software quality. With its criteria, it relates exclusively to the quality of the software as a 'product' ( product quality ), not or only indirectly (via the results) to the quality of the software development processes ( process quality ).
This ISO standard has been incorporated into the ISO / IEC 25000 standard and has been replaced by this same standard.
The following quality features are listed (partial features are only listed as suggestions in the appendix to the standard):
- Changeability / maintainability : How much effort does the implementation of given changes to the software require? - The effort required to carry out specified changes. Changes can include corrections, improvements or adaptations to changes in the environment, requirements or functional specifications.
- Analyzability: Expenditure to diagnose defects or causes of failure or to determine parts that need to be changed.
- Conformity: The degree to which the software complies with standards or agreements on changeability.
- Modifiability : Effort to implement improvements, to correct errors or to adapt to changes in the environment.
- Stability: the likelihood of unexpected effects of changes occurring.
- Testability : the effort required to test the changed software.
Usability : How much effort does the use of the software require of the users and how is it assessed by them? - Effort required for use and individual assessment of use by a specified or assumed user group. See also software ergonomics .
- Attractiveness : The application's appeal to the user.
- Usability : effort for the user to operate the application.
- Learnability: effort for the user to learn the application (for example operation, input, output).
- Conformity: The degree to which the software meets standards or usability agreements.
- Comprehensibility: effort for the user to understand the concept and the application.
Efficiency : What is the relationship between the performance level of the software and the resources used? - Relationship between the level of performance of the software and the scope of the operating resources used under specified conditions.
- Conformity: The degree to which the software meets standards or agreements on efficiency.
- Time behavior : response and processing times as well as throughput during function execution.
- Consumption behavior : Number and duration of the resources required to fulfill the functions. Resource consumption such as CPU time, hard disk access, etc.
Functionality : To what extent does the software have the required functions? - Presence of functions with defined properties. These functions meet the defined requirements.
- Appropriateness: Suitability of functions for specified tasks, for example task-oriented composition of functions from sub-functions.
- Security : Ability to prevent unauthorized access, both accidental and deliberate, to programs and data.
- Interoperability : Ability to interact with given systems.
- Conformity : Ability of the software product to comply with standards, conventions or legal provisions and similar regulations related to functionality.
- Compliance: Features of software that cause the software to comply with application-specific standards or agreements or legal provisions and similar regulations.
- Correctness : Delivering the correct or agreed results or effects, for example the required accuracy of calculated values.
Portability : How easily can the software be ported to another environment? - Suitability of the software so that it can be transferred from one environment to another. The environment can be an organizational, hardware or software environment.
- Adaptability: Ability of the software to adapt it to different environments.
- Interchangeability: Possibility of using this software instead of a specified other in the environment of that software, as well as the effort required for this.
- Installability: the amount of effort required to install the software in a defined environment.
- Coexistence : Ability of the software to work alongside another with similar or identical functions.
- Conformity: The degree to which the software meets standards or transferability agreements.
Reliability : Can the software maintain a certain level of performance under certain conditions over a certain period of time? - Ability of the software to maintain its level of performance under specified conditions for a specified period of time.
- Fault tolerance : the ability to maintain a specified level of performance in the event of software errors or non-compliance with its specified interface.
- Conformity: The degree to which the software meets standards or agreements on reliability.
- Maturity: Low frequency of failure due to fault conditions.
- Recoverability: the ability, in the event of failure, to restore the level of performance and recover the data directly affected. The time and effort required must be taken into account.