Terminal LU state requirements

When z/OS® Debugger accesses the terminal LU, the terminal LU must be in the following state:
  • It must be known to the z/OS Communications Server on the system which z/OS Debugger runs.
  • It must be marked secondary logical unit (SLU) enabled.
  • It must not be in session with any application.
You can determine whether a particular terminal LU meets these criteria by using the DISPLAY VTAM® operator command:
  1. Access the desired LU using your terminal emulator, and exit any session manager.
  2. On your system console, enter the following command, where name is the LU name: 
    DISPLAY NET,ID=name,SCOPE=ALL
  3. Inspect the output of the command for the following information:
    • The IST486I message indicates STATUS=ACTIV and DESIRED STATE=ACTIV, and an IST172I NO SESSIONS EXIST message is displayed.
    • The IST597I message indicates SLU ENABLED.
    • The IST934I message indicates that a DLOGMOD was specified.