You can define protected user IDs for started procedures associated with z/OS® UNIX, such as the kernel, the initialization started procedure, and daemons that are critical to the availability of your z/OS UNIX system. Defining the protected user IDs will prevent these user IDs from being revoked through inadvertent or malicious incorrect password or password phrase attempts, or from being used for other purposes, such as logging on to the system. For more information about protected user IDs, see z/OS Security Server RACF Security Administrator's Guide.