Analyze TCB structure

If a TCB was in control at the time of the error, use the IPCS subcommand SUMMARY TCBERROR to look at the TCB information and find the failing component. SUMMARY TCBERROR summarizes the control blocks for the failing address space. (To see all the fields in the control blocks, use SUMMARY FORMAT.) Scan the completion codes (field CMP) for each TCB to find the correct TCB. This report displays RBs from newest to oldest.

Figure 1 is an example of SUMMARY TCBERROR output. In this example the TCB at address 008E9A18 has a completion code of X'0C1.' The error occurred under this TCB. Once you have identified the failing TCB, you can follow the RB chain to the failing program.

Figure 1. Example: the SUMMARY TCBERROR report

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     NAME..... IEFSD060  ENTPT.... 00DA6308

  PRB: 008FFED0
     WLIC..... 00020006  FLCE.... 00C534A0  OPSW..... 070C2000 00DC766A
     LINK..... 008FFA10

  CDE: 00C534A0
     NAME..... IEESB605  ENTPT.... 00DC7000

  TCB:  008FF0D0
     CMP...... 00000000  PKF...... 80        LMP...... FF        DSP...... FF
     TSFLG.... 00        STAB..... 008FD210  NDSP..... 00002000
     JSCB..... 008FF4FC  BITS..... 00000000  DAR...... 00
     RTWA..... 00000000  FBYT1.... 00
     Task non-dispatchability flags from TCBFLGS4:
      Top RB is in a wait
     Task non-dispatchability flags from TCBFLGS5:
      Secondary non-dispatchability indicator
     Task non-dispatchability flags from TCBNDSP2:
      SVC Dump is executing for another task
  PRB: 008E9F20
     WLIC..... 00020001  FLCDE.... 00C4CA38  OPSW..... 070C1000  00DAC66E
     LINK..... 018FF0D0

  CDE: 00C4CA38
     NAME..... IEFIIC    ENTPT.... 00DA6000

  TCB: 008E9A18
     CMP...... 940C1000  PKF...... 80        LMP...... FF        DSP...... FF
     TSFLG.... 20        STAB..... 008FD180  NDSP..... 00000000
     JSCB..... 008FF33C  BITS..... 00000000  DAR...... 01
     RTWA..... 7FFE3090  FBYT1.... 08


SVRB: 008FD7A8
     WLIC..... 00020000  FLCDE.... 00000000  OPSW..... 070C1000  82569B38
     LINK..... 008FD638

  PRB: 008E9750
     WLIC..... 00020033  FLCDE.... 14000000  OPSW..... 070C1000  80CE9AEE
     LINK..... 008FD638

  SVRB: 008FD638
     WLIC..... 0002000C  FLCDE.... 00000000  OPSW..... 070C1000  825E9768
     LINK..... 008FD4C8

  SVRB: 008FD4C8
     WLIC..... 00020001  FLCDE.... 00000000  OPSW..... 070C0000  00C47D52
     LINK..... 008FD358

  SVRB: 008FD358
     WLIC..... 00020053  FLCDE.... 00000000  OPSW..... 075C0000  00D64EOC
     LINK..... 008FF4D8

  PRB: 008FF4D8
     WLIC..... 00020014  FLCDE.... 008FF3D8  OPSW..... 078D0000  00006EF2
     LINK..... 008E9A18

  CDE: 008FF3D8
     NAME..... SMFWT     ENTPT.... 00006EB0

In this example, the most current RB is the SVRB at address 008FD7A8. This is the SVC dump's RB. The ESTAE's RB is the PRB at 008E9750. The ESTAE issued an SVC 33. The RB for the recovery termination manager (RTM) is the SVRB at 008FD638. RTM issued an SVC C to attach the ESTAE. The X'0C1' abend occurred under the SVRB at 008FD4C8. The last interrupt was a 1 at the address indicated in the old PSW field (OPSW). The next RB in the chain shows an SVC X'53' (SMFWTM) had been issued. This is the code the X'0C1' occurred in.

For a scheduled dump, the abnormally terminating TCB can generally be found by scanning for a nonzero completion code. If there is no code, scan the system trace for the abend. The trace identifies the ASID number and TCB address for each entry. See Examining the system trace.

Use the STATUS or the STATUS REGS subcommand to find the data set name and the module name of the SVC dump requester.