The software quality standards defined in ISO 25010 comprise eight quality characteristics: Functional suitability, Reliability, Performance efficiency, Usability, Security, Compatibility, Maintainability, and Portability. ISO 9126 provides 6 characteristics and 27 sub-characteristics, while ISO 25010 provides 8 characteristics and 31 sub-characteristics. ISO 25010 is an eight software quality standards Functional suitability This characteristic represents the degree to which a product or machine gives abilities that meet stated and implied desires even as used underneath neath certain situations. This characteristic includes the following sub-developments.