Examining the system trace

The system trace table describes the events in the system leading up to the error. The trace table is helpful when the PSW does not point to the failing instruction, and to indicate what sequence of events preceded the abend.

IPCS option 2.7.4 formats the system trace. The report is long. IBM® recommends scrolling to the end of the report, then backing up to find the trace entry for the abend. Type an M on the command line and press F8 to scroll to the bottom of the report.

After you find the entry for the abend, start at the PSW where the dump was taken and track the events in the table to find where the failing instruction is in the code.

The system trace report marks important or significant entries with an asterisk. In Figure 1 “*SVC D” in the “IDENT CD/D” column identifies the PSW where the program took the dump. Prior to the SVC D are three PGM (program check) entries. PGM 001 has an asterisk next to it, indicating that the program check was unresolved. The next entry, RCVY PROG, identifies a recovery program that failed because it issued the SVC D a few entries later. See System trace to recognize significant entries in the system trace table.

Figure 1. Example: output from the IPCS subcommand SYSTRACE

PR  ASID TCB-ADDR  IDENT CD/D PSW----- ADDRESS-  UNIQUE-1 UNIQUE-2 UNIQUE-3
                                                 UNIQUE-4 UNIQUE-5 UNIQUE-6

⋮

 01 0094 00AF7D18   DSP       070C0000 81EA7000  00000000 00000000 0000800C
 01 0094 00AF7D18   SVC    78 070C0000 81EA7048  00000002 00000278 00000000
 01 0094 00AF7D18  SVCR    78 070C0000 81EA7048  00000000 00000278 03300D88
 01 0094 00AF7D18   PGM   010 070C0000 81EA704A  00040010 03300D8C
 01 0094 00AF7D18   PGM   011 070C0000 81EA704A  00040011 03300D8C
 01 0094 00AF7D18   SVC    77 070C2000 81EA7088  81EA7000 00000000 00050000
 01 0094 00AF7D18  SVCR    77 070C2000 81EA7088  00000000 00000000 40000000
 01 0094 00AF7D18  *PGM   001 070C0000 83300FAA  00020001 03300D8C
 01 0094 00AF7D18  *RCVY PROG                    940C1000 00000001 00000000
 02 0001 00000000   I/O   1A2 070E0000 00000000  0080000E 060246C0 0C000001
 02 0054 00AD7300   SRB       070C0000 810537E0  00000054 00F3C9F8 00F3CA40
 01 0054 00AF7D18   SSRV  12D          810B9CEE  00AF7D18 000C0000 00000000
 01 0094 00AF7D18   SSRV  12D          810B9D0E  00AF7D18 000B0000 00000000
 01 0094 00AF7D18   DSP       070C0000 810BF664  00000000 00000000 40000000
 01 0094 00AF7D18  *SVC     D 070C0000 810BF666  00000040 00000000 40000000
 01 0054 00000000  SSRV   10F          00000000  00F83E80 00AD7300 00AC5040