Which one is not a software quality model?

Answer: ISO 9000 is not a software quality model.

Short explanations:

• ISO 9126 / ISO/IEC 25010: Defines software product quality characteristics (functionality, reliability, usability, efficiency, maintainability, portability).

• Boehm Model: A software quality model that relates high-level quality attributes to measurable criteria and helps assess product quality.

• McCall Model: A software quality model defining factors and criteria (such as correctness, reliability, efficiency, integrity, usability) used to evaluate software quality.

• ISO 9000: A family of standards for quality management systems (process and organizational requirements for ensuring quality). It focuses on management processes and certification, not on defining software product quality characteristics, so it is not a software quality model.