Symbols Created by IPCS

IPCS uses the symbol X to represent the current address in the current dump. X is automatically given the NODROP attribute. You can specify X as an address parameter to many IPCS subcommands. Various IPCS subcommands might modify X as a result of their processing.

Many IPCS subcommands define symbols as part of their output. For example, to ask IPCS to find and display the ASVT wherever it is, specify:

list asvt structure(asvt)

If the symbol ASVT is not already in the symbol table, LIST locates it, verifies it, enters it in the symbol table with the attribute of STRUCTURE(ASVT), and lists it.

However, LIST displays the storage at the location pointed to from X'5820' if you specify:

list 5820.% structure(asvt)

The subcommand does not know if this really is the ASVT. It does not create a symbol table entry for ASVT, nor does it use such an entry if it already exists. In this example, you are telling the subcommand that the storage at the specified location is the ASVT. The subcommand verifies that the storage is the ASVT but does not make a symbol table entry for the ASVT.

When processing a stand-alone dump, IPCS analysis subcommands might have to simulate dynamic address translation (DAT). There are many control blocks that the subcommands use to do this translation. An IPCS subcommand that accepts a data description parameter may locate and validate the control blocks it needs to perform its function (if they are not already located) and make entries for them in the symbol table and storage map.

The FINDMOD, FINDUCB, RUNCHAIN, SCAN, and SUMMARY subcommands locate modules and control blocks in the current dump. FINDMOD locates a module, FINDUCB locates a UCB, RUNCHAIN processes a specified chain of control blocks, SUMMARY locates ASCBs. As each subcommand finds what it is looking for, it generates a name for it and puts that name in the symbol table along with the attributes of the module or control block it represents.

IPCS also adds symbols to the table when processing the CTRACE and GTFTRACE subcommands. Component buffer find routines produce symbols that describe buffers in a dump when processing the CTRACE subcommand. Processing for GTFTRACE adds a symbol that notes the wrap point of a wrapped trace data set.

The symbols created by IPCS are named according to a naming convention (see Naming Conventions for Special Symbols). You can refer to them by name once IPCS processes the subcommand that defines them.