ISRDDN is a utility that assists IBM® support in evaluating and solving problems. It provides a list of allocated ddnames, a list of system ENQs, a list of data sets causing system ENQ contention, and a means of viewing storage within a TSO user's address space. ISRDDN also provides some facilities for gathering information about your system environment.

You can start ISRDDN by issuing the commands TSO ISRDDN or DDLIST from any ISPF command line.

The allocated ddname list shows you all of the ddnames allocated to your TSO session. From the list you can perform functions such as Edit or Compress against individual data sets, ddnames, or sets of ddnames. You can also perform actions against the entire list of displayed ddnames.

The ENQ list, available by typing ENQ on the allocation list command line, shows you ENQs on your system. You can limit the size of the list by specifying the QNAME, RNAME, job, user or address space name, and system name.

The ENQ contention list, available by typing CON on the allocation list command line, shows you ENQ contentions on your system for data sets (QNAME SYSDSN).

You can Browse storage using the BROWSE primary command from the allocation list. You can only browse storage which an unauthorized program can see (private and common).

To invoke the ISRDDN program, type TSO ISRDDN on any ISPF command line.