Working with TDUMPs using IPCS

A TDUMP or Transaction Dump is generated from the MVS service IEATDUMP by default in the event of a program check or exception in the JVM. You can disable the generation of a TDUMP, but it is not recommended by IBM® Service.

A TDUMP can contain multiple Address Spaces. It is important to work with the correct address space associated with the failing java process.

To work with a TDUMP in IPCS, here is a sample set of steps to add the dump file to the IPCS inventory:

Browse the dump data set to check the format and to ensure that the dump is correct.
In IPCS option 3 (Utility Menu), suboption 4 (Process list of data set names) type in the TSO HLQ (for example, DUMPHLQ) and press Enter to list data sets. You must ADD (A in the command-line alongside the relevant data set) the uncompressed (untersed) data set to the IPCS inventory.
You can select this dump as the default one to analyze in two ways:
- In IPCS option 4 (Inventory Menu) type SD to add the selected data set name to the default globals.
- In IPCS option 0 (DEFAULTS Menu), change Scope and Source
```
Scope ==> BOTH (LOCAL, GLOBAL, or BOTH)

Source ==> DSNAME('DUMPHLQ.UNTERSED.SIGSEGV.DUMP') 
Address Space ==>  
Message Routing ==> NOPRINT TERMINAL 
Message Control ==> CONFIRM VERIFY FLAG(WARNING) 
Display Content ==> NOMACHINE REMARK REQUEST NOSTORAGE SYMBOL
```
  If you change the Source default, IPCS displays the current default address space for the new source and ignores any data entered in the address space field.

To initialize the dump, select one of the analysis functions, such as IPCS option 2.4 SUMMARY - Address spaces and tasks, which will display something like the following output and give the TCB address. (Note that non-zero CMP entries reflect the termination code.)

TCB: 009EC1B0                                                               
   CMP...... 940C4000  PKF...... 80        LMP...... FF        DSP...... 8C 
   TSFLG.... 20        STAB..... 009FD420  NDSP..... 00002000               
   JSCB..... 009ECCB4  BITS..... 00000000  DAR...... 00                     
   RTWA..... 7F8BEDF0  FBYT1.... 08                                         
   Task non-dispatchability flags from TCBFLGS5:                            
    Secondary non-dispatchability indicator                                 
   Task non-dispatchability flags from TCBNDSP2:                            
    SVC Dump is executing for another task                                  

SVRB: 009FD9A8                                                              
   WLIC..... 00000000  OPSW..... 070C0000  81035E40                         
   LINK..... 009D1138                                                       

PRB: 009D1138                                                               
   WLIC..... 00040011  OPSW..... 078D1400  B258B108                         
   LINK..... 009ECBF8                                                       
   EP....... DFSPCJB0  ENTPT.... 80008EF0                                   

PRB: 009ECBF8                                                               
   WLIC..... 00020006  OPSW..... 078D1000  800091D6                         
   LINK..... 009ECC80

For more information about IPCS on z/OS, see the documentation for your version of z/OS. For example: Getting started with IPCS on z/OS.