text: **User Security Exit (ARSUSEC on z/OS only)**
  On z/OS, the**ARSUSEC**exit invokes the**ARSUSECZ**security exit module. The security exit allows 
  the communication with an external security manager, such as RACF, which then determines 
  whether the specific activity is allowed. 
  
  When you enable the exits to implement the required level or type of security, the user ID 
  must be defined for both TSO and Content Manager OnDemand. 
  
  Figure 6-12 is an overview of the security system exits interface. 