Software Quality Characteristics (ISO/IEC 25010)｜Organizing the 8 Quality Characteristics for the IT Passport Exam

What is ISO/IEC 25010?

ISO/IEC 25010 is an international standard that uniformly defines software quality characteristics. Its former name was ISO/IEC 9126, and it was revised to 25010 in 2011. This standard classifies software quality into 8 main characteristics. In the IT Passport exam, questions asking about the names and content of these 8 characteristics appear frequently.

List of 8 Quality Characteristics

Details of Each Characteristic

Functional Suitability

Functional Suitability consists of three sub-characteristics: functional completeness, functional correctness, and functional appropriateness. Simply put, it is a characteristic that evaluates "whether the system provides the functions described in the specification document." In the exam, it is asked in questions like "whether the functions that meet the requirements are implemented."

Performance Efficiency

Performance Efficiency is a characteristic related to time behavior, resource utilization, and capacity. Specifically, it evaluates the system's processing efficiency, such as response time and CPU/memory usage. For example, it is often asked in questions like "whether the screen switches within 1 second."

Reliability

Reliability has sub-characteristics of availability, maturity, fault tolerance, and recoverability. In a word, it is "the property of being hard to break and, even if broken, recovering quickly." In the exam, numerical values like "99.9% uptime" are often presented as examples of reliability.

Security

Security is a characteristic encompassing confidentiality, integrity, non-repudiation, accountability, and authenticity. It evaluates the ability to prevent unauthorized access and protect data. For those who want to deepen their technical understanding, also refer to the articles on encryption basics and the difference between authentication and authorization.

Maintainability

Maintainability consists of sub-characteristics: modularity, reusability, analyzability, modifiability, and testability. It is a characteristic that evaluates "whether the code is highly readable and easy to modify or add features later." It appears in questions about the ease of refactoring and testing.

Portability

Portability has sub-characteristics of adaptability, installability, and replaceability. It evaluates how smoothly software can be migrated when operating across clouds or operating systems. In the exam, it is asked from the perspective of "whether it works the same way in different environments."

Key Points for the IT Passport Exam

In the exam, questions matching the names and content of the 8 quality characteristics appear frequently. Questions that ask you to select specific examples for each characteristic are also common. Also, be sure to remember that ISO/IEC 25010 itself is the standard that defines software quality characteristics.

Typical Patterns in Past Exam Questions

• "What quality characteristic does a 99.9% uptime rate correspond to?" type → Reliability
• "What does ease of screen operation correspond to?" type → Usability

Related Terms

• ISO standards (ISO9001・14001・27001)
• Testing techniques (testing techniques)
• System development process (system development process flow)

Study Tips

Memorizing the 8 characteristics with the mnemonic "Fu, Pe, Co, Us, Re, Se, Ma, Po" (Functional, Performance, Compatibility, Usability, Reliability, Security, Maintainability, Portability) helps them stick in your memory. Associate one representative numerical value or indicator with each characteristic. For Security, in addition to CIA (Confidentiality, Integrity, Availability), you also need to cover non-repudiation and authenticity.

Summary

If you firmly grasp the names and content of the 8 quality characteristics and the existence of ISO/IEC 25010, you can score points on related questions. For more comprehensive practice on the Management domain, use the Management summary, and to challenge yourself with full-format questions, use the mock exam.