If you suspect that a non-terminating loop is occurring during VTAM processing, you will need to collect some basic diagnostic information before canceling the VTAM partition. The diagnostic information will assist the VTAM support team in diagnosing the problem. VTAM's failure to respond to a VTAM operator command may be an indication of a non-terminating loop.
Resolving the problem
How you collect VTAM diagnostic information for a non-terminating loop before you cancel the partition depends on whether VSE is native on the CPU or a guest of VM:
- When VSE is native on the CPU, stop the processor and instruction-step the CPU to get the PSWs of the loop.
- When VSE is a guest of VM, issue the #CP TRACE I ALL command to obtain the PSWs. Use the #CP D P G command to display the PSW and REGS several times in order to trace the loop.