Category: quality-management

(Figure:source ISO25010 document)

The material of ISO is unfortunate not open. But since quality matters and ISO 25010 is used heavily for managing quality aspects within business IT systems a short overview.

Functionality

Functionality: A set of attributes that bear on the existence of a set of functions and their specified properties. The functions are those that satisfy stated or implied needs.

• Functional suitability: Degree to which a product or system provides functions that meet stated and implied needs when used underspecified conditions.
• Functional completeness : Degree to which the set of functions covers all the specified tasks and user objectives.
• Functional correctness : Degree to which a product or system provides the correct results with the needed degree of precision.
• Functional appropriateness : Degree to which the functions facilitate the accomplishment of specified tasks and objectives.

Reliability

Reliability: A set of attributes that bear on the capability of software to maintain its level of performance under stated conditions for a stated period of time. Attributes:

• Reliability:Degree to which a system, product or component performs specified functions under specified conditions for a specified period of time.
• Maturity : Degree to which a system, product or component meets needs for reliability under normal operation.
• Availability : Degree to which a system, product or component is operational and accessible when required for use.
• Fault tolerance : Degree to which a system, product or component operates as intended despite the presence of hardware or software faults.
• Recoverability : Degree to which, in the event of an interruption or a failure, a product or system can recover the data directly affected and re-establish the desired state of the system.

Performance Efficiency

A set of attributes that bear on the relationship between the level of performance of the software and the amount of resources used, under stated conditions.

• Performance efficiency: Performance relative to the amount of resources used under stated conditions.
• Time behaviour : Degree to which the response and processing times and throughput rates of a product or system, when performing its functions, meet requirements.
  Resource utilization : Degree to which the amounts and types of resources used by a product or system, when performing its functions, meet requirements.
• Capacity :  Degree to which the maximum limits of a product or system parameter meet requirements.

Compatibility

Compatibility:Degree to which a product, system or component can exchange information with other products, systems or components, and/or perform its required functions, while sharing the same hardware or software environment.

• Co-existence : Degree to which a product can perform its required functions efficiently while sharing a common environment and resources with other products, without detrimental impact on any other product.
• Interoperability : Degree to which two or more systems, products or components can exchange information and use the information that has been exchanged.

Usability

Usability:Degree to which a product or system can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use.

• Appropriateness recognizability : Degree to which users can recognize whether a product or system is appropriate for their needs.
• Learnability : Degree to which a product or system can be used by specified users to achieve specified goals of learning to use the product or system with effectiveness, efficiency, freedom from risk and satisfaction in a specified context of use.
• Operability : Degree to which a product or system has attributes that make it easy to operate and control.
• User error protection : Degree to which a system protects users against making errors.
• User interface aesthetics : Degree to which a user interface enables pleasing and satisfying interaction for the user.
• Accessibility : Degree to which a product or system can be used by people with the widest range of characteristics and capabilities to achieve a specified goal in a specified context of use.

Security

Security:Degree to which a product or system protects information and data so that persons or other products or systems have the degree of data access appropriate to their types and levels of authorization.

• Confidentiality : Degree to which a product or system ensures that data are accessible only to those authorized to have access.
• Integrity : Degree to which a system, product or component prevents unauthorized access to, or modification of, computer programs or data.
• Non-repudiation : Degree to which actions or events can be proven to have taken place, so that the events or actions cannot be repudiated later.
• Accountability : Degree to which the actions of an entity can be traced uniquely to the entity.
• Confidentiality : Degree to which a product or system ensures that data are accessible only to those authorized to have access.
• Authenticity : Degree to which the identity of a subject or resource can be proved to be the one claimed.

Maintainability

• Maintainability:Degree of effectiveness and efficiency with which a product or system can be modified by the intended maintainers.
• Modularity : Degree to which a system or computer program is composed of discrete components such that a change to one component has minimal impact on other components.
• Reusability :Degree to which an asset can be used in more than one system, or in building other assets.
• Analysability : Degree of effectiveness and efficiency with which it is possible to assess the impact on a product or system of an intended change to one or more of its parts, or to diagnose a product for deficiencies or causes of failures, or to identify parts to be modified.
• Modifiability : Degree to which a product or system can be effectively and efficiently modified without introducing defects or degrading existing product quality.
• Testability : Degree of effectiveness and efficiency with which test criteria can be established for a system, product or component and tests can be performed to determine whether those criteria have been met.

Transferability

• Portability:Degree of effectiveness and efficiency with which a system, product or component can be transferred from one hardware, software or other operational or usage environment to another
• Adaptability : Degree to which a product or system can effectively and efficiently be adapted for different or evolving hardware, software or other operational or usage environments.
• Installability : Degree of effectiveness and efficiency with which a product or system can be successfully installed and/or un-installed in a specified environment.
• Replaceability : Degree to which a product can replace another specified software product for the same purpose in the same environment.

 

Note that when you do a critical review on ISO20510 you will find that missing in ISO25010 is:

• Functional requirements
• Compliance (e.g. with laws, standards) requirements
• Documentation, Support and Training requirements and of course:
• Project Timing requirements
• Project Budget requirements

When creating business IT documentation (e.g. IT architectures/designs) following these rules will help for producing sound documentation:

1. Documentation should be written from the point of view of the reader, not the writer.
2. IT Documentation should be organized for ease of reference, not ease of reading. A document may be read from cover to cover at most once, and probably never. But a document is likely to be referenced hundreds or thousands of times.
3. Avoid repetition. Each kind of information should be recorded in exactly one place. This makes documentation easier to use and much easier to change as it evolves. It also avoids confusion.
4. Avoid unintentional ambiguity. In some sense, the point of architecture is to be ambiguous. However unplanned ambiguity is when documentation can be interpreted in more than one way, and at least one of those ways is incorrect. A well-defined notation with precise semantics goes a long way toward eliminating whole classes of linguistic ambiguity from a document. This is one area where architecture description languages help a great deal, but using a formal language isn’t always necessary.
5. Standardize your documentation. Use always the same templates for the same documents within your organization. Even better: Make use of de-facto standardizations that also make sense for people outside your organization, since you will be working with many people outside your organization during the life cycle of your product. A standard organization offers many benefits. It helps the reader navigate the document and find specific information quickly.
6. Record rationale. So document decisions made. Recording rationale will save you enormous time in the long run, although it requires discipline to record in the heat of the moment. It will prevent the same discussions over and over again and everyone knows why the chosen path is taken.
7. Keep it current. Documentation that is out of date, does not reflect truth, and does not obey its own rules for form and internal consistency will not be used. Documentation that is kept current and accurate will be used.
8. Review documentation for fitness of purpose. Only the intended users of a document will be able to tell if it contains the right information presented in right way.