List two other system properties that are sometimes considered to be dependability properties.

List two other system properties that are sometimes considered to be dependability properties.
Ans: 1. Maintainability: As systems are used, new requirements emerge and it is important to maintain the usefulness of a system by changing it to accommodate these new requirements. Maintainable software is software that can be adapted economically to cope with new requirements, and where there is a low probability that making changes will introduce new errors into the system.
2. Survivability: A very important attribute for Internet-based systems is survivability. Survivability is the ability of a system to continue to deliver service whilst under attack and, potentially, whilst part of the system is disabled. Work on survivability focuses on identifying key system components and ensuring that they can deliver a minimal service. Three strategies are used to enhance survivability—resistance to attack, attack recognition, and recovery from the damage caused by an attack.