What does system-level security primarily deal with?

System-level security primarily deals with ensuring that information is processed and managed appropriately across different security classifications. This means that the system is designed to handle information in a way that respects its sensitivity and access policies, particularly when there are various classifications of data that may have different handling requirements. Configuring systems to process information with incompatible classifications can lead to security vulnerabilities, so robust system-level security identifies and mitigates these risks.

While preventing physical access to computers, assigning unique identifiers to users, and monitoring system performance are all important aspects of overall IT security and system management, they fall under more specific domains. Physical access control pertains to physical security measures, user identification relates to authentication processes, and performance monitoring deals with the operational aspect of systems rather than directly addressing the security implications of data classifications. Thus, they are not the primary focus of system-level security.