Content of the trace records

You can evaluate DC trace records while debugging errors, building keywords, or evaluating APAR descriptions.

You can evaluate DC trace records during any of the following tasks:

  • Debugging user errors in exit routines or user modifications relating to communications
  • Debugging errors in other entities in the communication network (such as programmable terminals or other host processors)
  • Building a keyword string to search for known problems
  • Evaluating existing APAR descriptions to isolate problems that are most like the one you are experiencing

The first line of each trace record shows the ID: 

 ID= xxx    SEGNO= mm RECNO= nnnnnnnn TIME HH.MM.SS.TT DATE YY.DDD

xxx can be any of the following trace record identifiers (IDs):1

ID
Description
A xx
Communication analyzer activity (DFSICIO0)
AERx
Access method error
C xx
Communication analyzer activity (DFSCIOC0 in DFSICIO0)
CI04
TM shared queues re-read error detected
CIO2
Device-dependent module (DDM) SDC read for output
CIO3
Device-dependent module (DDM) conditional SDC wash output
CMEA
Before calling Message Control/Error exit DFSCMUX0
CMEB
After calling Message Control/Error exit DFSCMUX0
CMEI
Message Control/Error exit interface processing
COFC
Entry to the output format control, MFS-supported devices (DFSCOFC0)
CRTU
Output User Creation user exit routine failure
CTTR
ISC TCPIP Trace ABORT.
CVCT
VTAM® trace. This log record is written even though DC trace is not active on the terminal/link.
CVCV
XRF class 2 takeover trace. This log record is written for XRF class 2 terminals during takeover, even though DC trace is not active on the terminal.
D xx
Device-dependent module (DDM) activity
DDxx
Output processing by DFSCOFC0
DSIM
SIMLOGON attempt of a dynamic terminal
ESIM
SIMLOGON error for a dynamic terminal
FERR
MFS-block fetch error
FESx
Front-end switch user exit routine activity
FEXT
Before field edit exit routine
FMTx
Message Format Service activity (MFS)
HCSW
XRF class 1 takeover trace. This log record is written for XRF class 1 terminals during takeover, even though DC trace is not active on the terminal.
ICLR
Message router activity
INIT
Device-dependent module (DDM) for ISC TCP/IP that sends session initiation requests.
IRxx
Device-dependent module (DDM) for ISC TCP/IP that reads input messages that use the IBM® CICS® Transaction Server for z/OS® IPIC protocol.
IWxx
Device-dependent module (DDM) for ISC TCP/IP that builds output messages that use the CICS IPIC protocol.
MFSP
MFS activity to detect change in the content of a protected field that is in the input from a 3270 or SLU2 device. Set MFSPFV=Y in the DFSDCxxx member of the IMS PROCLIB data set to configure this option. This log record is written even though DC trace is not active on the terminal.
MSGS
Device-dependent module (DDM) for ISC TCP/IP that sends messages that use the CICS IPIC protocol.
MTRP
Block verification error
RESP
Device-dependent module (DDM) for ISC TCP/IP that sends ACK/NAK messages that use the CICS IPIC protocol.
SDC1
Device-dependent module (DDM) SDC output read error
SDC2
Device-dependent module (DDM) SDC message reread error
SEXT
Before segment edit exit routine
SGNX
Signon user exit routine failure
SPCL
Close spool data set
SPOP
Open spool data set
SPRE
Read spool data set
SPWR
Write spool data set
TERM
Device-dependent module (DDM) for ISC TCP/IP that sends session termination requests.
TRCE
Non-SNA 3270 error
VTPO
Non-posting of ECB trace (DFSVTPO0)

Exception: MSC has its own analyzer module and entry types.

The table below shows the types of data communication (DC) trace records and what each trace record contains. Some of the acronyms used in the table are:

SEG
Segment (DECAREA buffer)
MFS
MFS input work/MFS output work/MFS protect work
QBUF
Queue buffer
IOPUF
TP buffer
S25
Save area 2-5
SALL
Save area all
Table 1. DC trace records
Trace ID Function Traced by When traced or /TRACE option What is traced
A01 Process input. 1 DFSICIO0 9 ALL, DDM CTB, CLB, CXB, CRB, CIB, CCB, QBUF, IOBUF, INPCNTS, OUTCNTS, EMHB 2
A02 Do read. 1 DFSICIO0 9 ALL, DDM CTB, CLB, CXB, CRB, IOBUF, EMHB 2
A03 What is next. DFSICIO0 9 ALL, DDM CTB, CLB, CRB, CTT
A04 Get Next segment. DFSICIO0 9 ALL, DDM CTB, CLB, CNT
A05 Do write. 1 DFSICIO0 9 ALL, DDM CTB, CLB, CXB, CRB, CCB, IOBUF, EMHB 2
A06 After good write. DFSICIO0 9 ALL, DDM IOB, CTB, CLB, CXB, CRB, CCB
A07 After bad write. 1 DFSICIO0 9 ALL, DDM IOB, CTB, CLB, CRB, CCB, IOBUF, EMHB 2
A08 Cancel message, do not DEQ. DFSICIO0 9 ALL, DDM CTB, CLB, CRB
A09 Generate system message. 1 DFSICIO0 9 ALL, DDM CTB, CLB, CRB, MFS
A10 Quiesce without stopping. DFSICIO0 9 ALL, DDM CTB, CLB, CRB, CCB
A11 Retrieve last DEQD message. DFSICIO0 9 ALL, DDM CTB, CLB, CNT, CRB
A12 Wait for ASYNC I/O or output ENQ. DFSICIO0 9 ALL, DDM CTB, CLB, CRB, CCB, IOBUF, EMHB 2
AER1 Access method error. DFSICIO0 9 Always CTB, CLB, CNT, QBUF, SALL, CTT, PCB
AER2 Access method error. 3, 1 DFSICIO0 9 Always IOB, CTB, CLB, CNT, CXB, CRB, CIB, CCB, QBUF, IOBUF, SALL, CTT, PCB, EMHB 2
C00 Get queue buffer. DFSICIO0 9 ALL, MFS CTB, CNT, CIB, SALL
C01 Reposition queue buffer. DFSICIO0 9 ALL, MFS CTB, CNT, CIB, SALL
C02 Get Next. DFSICIO0 9 ALL, MFS CTB, CNT, CIB, SALL
C03 DEQ output. DFSICIO0 9 ALL, MFS CTB, CNT, CIB, SALL
C04 Place output back in queue. DFSICIO0 9 ALL, MFS CTB, CNT, CIB, SALL
C05 Find output. DFSICIO0 9 ALL, MFS CTB, CNT, CIB, SALL
C06 Get new output message or QMGR call. DFSICIO0 9 ALL, MFS CTB, CNT, CIB, SALL
C07 Free input buffer. DFSICIO0 9 ALL, MFS CTB, CNT, CIB, SALL
C08 Get output buffer. DFSICIO0 9 ALL, MFS CTB, CNT, CIB, SALL
C09 User output edit. DFSICIO0 9 ALL, MFS CTB, CNT, CIB, SALL
C10 Call queue MGR. DFSICIO0 9 ALL, MFS CTB, CNT, CIB, SALL
C11 Get device-dependent module (DDM) work buffer. DFSICIO0 9 ALL, MFS CTB, CNT, CIB, SALL
C12 Free device-dependent module (DDM) work buffer. DFSICIO0 9 ALL, MFS CTB, CNT, CIB, SALL
C13 Free receive-any buffer. DFSICIO0 9 ALL, MFS CTB, CNT, CIB, SALL
CIO2 Device-dependent module (DDM) SDC read output DFSCIO20 ALL DDM copy ctl blk list from CVCT entry
CIO3 Device-dependent module (DDM) SDC wash output DFSCIO30 ALL DDM copy ctl blk list from CVCT entry
CMEA Before call MSG CTRL Error exit. DFSCMEI0 Before call DFSCMUX0 If ITASK is a CLB or LLB: CTB, CLB, CRB, QBUF, IOBUF, INP/OUTP CNTS, DDM, MSNB
CMEB After call MSG CTRL Error exit. DFSCMEI0 After call DFSCMUX0 If ITASK is a CLB or LLB: CTB, CLB, CRB, QBUF, IOBUF, INP/OUTP CNTS, DDM, MSNB If ITASK is a PST: PST, MSGPRFX, SMB, MSNB
CMEI Error procedure in DFSCMEI0. DFSCMEI0 On some errors If ITASK is a CLB or LLB: CTB, CLB, CRB, QBUF, IOBUF, INP/OUTP CNTS, DDM, MSNB If ITASK is a PST: PST, MSGPRFX, SMB, MSNB
COFC Let MFS edit output. DFSICIO0 9 ALL, DDM CTB, CLB, CNT, CRB, CIB, IOBUF, EMHB 2
CRTU Output User Creation exit routine failure. DFSCRTU0 Always See notes10
CTTR ISC TCP/IP Trace ABORT DFSCTTR0 All, DDM CTB,CLB,CRB,SPQB, SPQBEXT,INP_CNTS, CTT, IOBUF, LU6WA, TCPWORK, CTBWORK
CVCT VTAM TRACE/ABORT. 1 DFSCVCT0 ALL, DDM CTB, CLB, CNT, CRB, IOBUF, CTT, INPCNTS, EMHB 2
CVCV XRF class 2 takeover. 1 DFSCVCV0 Always CLB, CTB, CTT, LLB, LTB, LXB, LU6WA, CNT, CRB, SPQB, CTC, MSNB, EMHB, IOBUF, DDM
D01 Write setup. DFSICIO0 9 ALL, DDM CTB, CLB, CNT, CRB, CIB, QBUF, S25
D02 Write interrupt. 1 DFSICIO0 9 ALL, DDM IOB, CTB, CLB, CRB, IOBUF, S25, EMHB 2
D03 Read setup. DFSICIO0 9 ALL, DDM CTB, CLB, CNT, CRB
D04 Read interrupt. 1 DFSICIO0 9 ALL, DDM IOB, CTB, CLB, CRB, IOBUF, S25, EMHB 2
D05 Cleanup. DFSICIO0 9 ALL, DDM IOB, CTB, CLB, CNT, CXB, CRB, CIB, CCB, MFS, QBUF, IOBUF, SALL, EMHB 2
D07 LOGON. 1 DFSICIO0 9 ALL, DDM CTB, CLB, CNT, CRB
DD6M Output build (MFS). DFSCOFC0 ALL, DDM CTB, CLB, CNT, CRB, CIB, SEG, MFS, IOBUF, S25, EMHB 2
DD6S Output build (Non-MFS). DFSCOFC0 ALL, DDM CTB, CLB, CNT, CRB, CIB, IOBUF, S25, EMHB 2
DD8 Prepare for output. DFSCOFC0 ALL, DDM CTB, CLB, CNT, CRB, CIB, IOBUF, S25, EMHB 2
DDM1 Write set up through COFC. DFSCOFC0 ALL, DDM CTB, CLB, CNT, CRB, CIB, MFS, IOBUF, S25, EMHB 2
FERR MFS block fetch error. 3 DFSCFEO0 Always CIB, CTT, MFSBPCA, MFSTRACE 4
FES1 Entry to front end switch user exit. DFSICIO0 9   CTB, CLB, CNT, QBUF, S25
FES2 Exit from front end switch user exit. DFSICIO0 9   CTB, CLB, CNT, QBUF, S25
FEXT 5 Before field edit exit. DFSCFEI0 MFS CTB, CIB
FMT1 Return from DFSFEIO or unformatted input. DFSICIO0 9 ALL, MFS CTB, CLB, CIB, IOBUF, EMHB 2
FMT2 MFS go to DFSFEIO formatted input. DFSICIO0 9 ALL, MFS CTB, CLB, CIB, IOBUF, EMHB 2
FMT3 MFS complete process MSG segment. DFSICIO0 9 ALL, MFS CTB, CLB, CIB, MFS, QBUF
FMT4 Get next input. DFSICIO0 9 ALL, MFS CTB, CLB, CIB
FMT6 Clean up resources. DFSICIO0 9 ALL, MFS CTB, CLB, CIB
HCSW XRF class 1 takeover. 1 DFSHCSW0 Always IOBUF, CNT, CRB, CTT, CTB, CLB
ICLR Message router. DFSICLR0 Always CTB, CLB, CTT, PCB
INIT Device-dependent module (DDM) for ISC TCP/IP that sends session initiation requests. DFSCT7E0 All, DDM CTB,CLB,CRB,SPQB, SPQBEXT,INP_CNTS, CTT, IOBUF, LU6WA, TCPWORK, CTBWORK
IR4B Device-dependent module (DDM) for ISC TCP/IP that reads input messages that use the CICS IPIC protocol. DFSCT4B0 All, DDM CTB,CLB,CRB,SPQB, SPQBEXT,INP_CNTS, CTT, IOBUF, LU6WA, TCPWORK, CTBWORK
IR7A Device-dependent module (DDM) for ISC TCP/IP that reads input messages that use the CICS IPIC protocol. DFSCT7A0 All, DDM CTB,CLB,CRB,SPQB, SPQBEXT,INP_CNTS, CTT, IOBUF, LU6WA, TCPWORK, CTBWORK
IR8B Device-dependent module (DDM) for ISC TCP/IP that reads input messages that use the CICS IPIC protocol. DFSCT8B0 All, DDM CTB,CLB,CRB,SPQB, SPQBEXT,INP_CNTS, CTT, IOBUF, LU6WA, TCPWORK, CTBWORK
IW1B Device-dependent module (DDM) for ISC TCP/IP that builds output messages that use the CICS IPIC protocol.. DFSCT1B0 All, DDM CTB,CLB,CRB,SPQB, SPQBEXT,INP_CNTS, CTT, IOBUF, LU6WA, TCPWORK, CTBWORK
IW3B Device-dependent module (DDM) for ISC TCP/IP that builds output messages that use the CICS IPIC protocol. DFSCT3B0 All, DDM CTB,CLB,CRB,SPQB, SPQBEXT,INP_CNTS, CTT, IOBUF, LU6WA, TCPWORK, CTBWORK
IW6A Device-dependent module (DDM) for ISC TCP/IP that builds output messages that use the CICS IPIC protocol. DFSCT6A0 All, DDM CTB,CLB,CRB,SPQB, SPQBEXT,INP_CNTS, CTT, IOBUF, LU6WA, TCPWORK, CTBWORK
IW7A Device-dependent module (DDM) for ISC TCP/IP that builds output messages that use the CICS IPIC protocol. DFSCT7A0 All, DDM CTB,CLB,CRB,SPQB, SPQBEXT,INP_CNTS, CTT, IOBUF, LU6WA, TCPWORK, CTBWORK
IW8A Device-dependent module (DDM) for ISC TCP/IP that builds output messages that use the CICS IPIC protocol. DFSCT8A0 All, DDM CTB,CLB,CRB,SPQB, SPQBEXT,INP_CNTS, CTT, IOBUF, LU6WA, TCPWORK, CTBWORK
MFSP MFS detected that protected data that is in the input is altered. DFSCFEI0 Always CTB, CLB, CIB, MFS, IOBUF
MSGS Device-dependent module (DDM) for ISC TCP/IP that sends messages that use the CICS IPIC protocol. DFSCT7E0 All, DDM CTB,CLB,CRB,SPQB, SPQBEXT,INP_CNTS, CTT, IOBUF, LU6WA, TCPWORK, CTBWORK
MTRP 8 Block verification error. DFSCFEO0   CLB, CIB, MFS, CTT
MTRP 7 Block verification error. DFSCFEI0   CLB, CIB, MFS, CTT
RESP Device-dependent module (DDM) for ISC TCP/IP that sends ACK/NAK messages that use the CICS IPIC protocol. DFSCT7E0 All, DDM CTB,CLB,CRB,SPQB, SPQBEXT,INP_CNTS, CTT, IOBUF, LU6WA, TCPWORK, CTBWORK
SDC1 Device-dependent module (DDM) SDC read error DFSCIO20 ALL DDM copy ctl blk list from CVCT entry
SDC2 Device-dependent module (DDM) SDC reread error DFSICIO4 ALL DDM copy ctl blk list from CVCT entry
SEXT 6 Before segment edit exit. DFSCFEI0 MFS CTB, CIB
TERM Device-dependent module (DDM) for ISC TCP/IP that sends session termination requests. DFSCT7E0 All, DDM CTB,CLB,CRB,SPQB, SPQBEXT,INP_CNTS, CTT, IOBUF, LU6WA, TCPWORK, CTBWORK
TRCE Non-SNA 3270 error. DFSDN130, DFSDN140, DFSDS060 Always IOB, CTB, CLB, S25, CTT
VTPO Rejected posting of ECB. DFSVTPO0 ALL, DDM See notes11
Notes:
  1. See Diagnosing line and terminal problems for more information on this trace code.
  2. Fast Path EMHB buff traces (if present) with I/O buffers
  3. Module return code saved in CLBTEMP4
  4. Return codes from DFSFFRH0 (block fetch), MFSTRACE (when in MFSTEST) or MFSBPCA (when not in MFSTEST); MFSTRACE=MFSTEST trace parameters, MFSBPCA=MFS Buffer Pool Control Area:
    Offset in hex
    0
    Current pool space in use
    4
    Maximum space used
    5
    Status flag

              X'80'    I/O active for a task
              X'40'    Task(s) queued for I/O
              X'20'    A task dequeued and posted

    9
    Error status

              X'BB'    BLDL error
              X'FF'    READ error

    A
    Block name for BLDL error
    10
    BLDL return code on error
    12
    Sense from read error
    14
    CSW status from read error
    16
    Block name for read error
    20
    List for BLDL macro
  5. Besides CIB and CTB:
    PARMLIST
    Parameter list to be passed to EXIT
    FIELD
    Field data before exit
  6. Besides CIB and CTB:
    PARMLIST
    Parameter list to be passed to EXIT
    SEGMENT
    Segment data before exit
  7. SEXT is logged if TRAP 1 is set by /TRACE and a buffer overwrite occurs.
  8. MTRP is logged if TRAP 1 is set by /TRACE and a buffer overwrite occurs. In addition to the blocks, the DIF/DOF, MID/MOD, MFBP, and FRE are traced. If in output, R9 is also traced.
  9. The MSNB control block content is traced by DFSICIO0 if the /DEQ LTERM, /DEQ NODE, or the /DEQ MSNAME command is entered with the PURGE or PURGE1 keywords.
  10. The CRTU trace entry is mapped in Format of 6701 log record with CRTU identifier.
  11. The VTPO trace entry is mapped in Format of the 6701 log record with VTPO identifier.
1 An asterisk (*) in this list is a wildcard character, meaning that any character can replace the asterisk.