In version 4.2 of ISPF IBM launched an undocumented feature called ISRDDN. This feature shows all your TSO allocations and is able to manipulate them in different ways. In OS/390 version 2.5 ISRDDN has been extended with a lot of new functions including ways to show all kinds of enqueues on the LPAR that your current TSO-sessions is running on.
ISRDDN is simply started by typing TSO ISRDDN on any command line in your ISPF environment. In some installations ISRDDN is not installed. Ask your TSO/ISPF systems programmet to install it, because you can't live without it. Some installations has made it available just by typing ISRDDN as an ISPF command. There is an online documentation provided. Just press HELP to see it. In the early versions of the product it was only documented in help screens, but the latest versions of ISPF provides some documentation in the ISPF manuals. Try out the following link:
If you want to use the enqueue displays just type ENQ as a primary command in ISRDDN. It only works in the proper versions of the product. If you ever heard of the product TASID, I can strongly reccomend it. ISRDDN is a part of TASID, and TASID can show a lot of information about the actual LPAR and other interesting stuff like browsing all accessible storage for your TSO session. Try TSO TASID, just to see if it is available on your installation. If TASID isn't available, you can read more about it and download it using this link: