What is not part of the system security?

The choice that is not part of system security is checking for adequate power. While ensuring that a system has a reliable power supply is critical for its operation, it primarily pertains to the functionality and availability of the system rather than the security aspect itself. System security focuses on protecting data and resources from unauthorized access and tampering, which is more directly related to the other options listed.

System access refers to the controls put in place to ensure that only authorized users can access specific systems and data, making it a fundamental part of security measures. Backing up data is essential to protect against data loss due to failures, cyber-attacks, or other incidents, thereby maintaining data integrity and availability. Secure files involves implementing measures to ensure that sensitive information is stored safely, minimizing risks of breaches or data leaks.

In summary, while checking for adequate power ensures operational reliability, it does not fall under the definition and framework of system security, which is primarily concerned with safeguarding information and preventing unauthorized access.