Using dump core *START,DC

Function

Use *START,DC, to:

Display all active traps.
Alter data in storage.
Display information about loaded modules.
Display control blocks specified on the OPTION= parameter.
Display the contents of a spool record.
Specify the device to receive the dump core output. This can also be specified when the dump core DSP is called.
Display all patch areas.
Display the contents of the registers and take a snapshot of storage at a waiting trap.
Display the contents of the registers at a waiting trap.

You can also use the *START,DC,TRAP command to:

Print snapshots taken as a result of trap or while at a waiting trap.
Intercept the processing of JES3 and print the contents of storage.
Resume processing after a waiting trap.
Deactivate waiting or the taking of snapshots at a trap.
Activate waiting or the taking of snapshots at a trap.
Inform JES3 that traps are set.

Syntax


>>-+-*START-+--,--DC-------------------------------------------->
   '-*S-----'          

>--+-,--ACTIVE----------------------------------------------------------------------------------------+-->
   +-,--C--=--adr--+---------------------------------------------------------+------------------------+   
   |               +-,--S--=--hhh--+---------------------------------------+-+                        |   
   |               |               |             .-0---------------------. | |                        |   
   |               |               '-,--BASE--=--+-adr-------------------+-' |                        |   
   |               |                             '-module--+-----------+-'   |                        |   
   |               |                                       '-,SEQ=--nn-'     |                        |   
   |               |          .-20-.                                         |                        |   
   |               +-,--B--=--+-nn-+-----------------------------------------+                        |   
   |               |             .-0---------------------.                   |                        |   
   |               '-,--BASE--=--+-adr-------------------+-------------------'                        |   
   |                             '-module--+-----------+-'                                            |   
   |                                       '-,SEQ=--nn-'                                              |   
   +-,--FIND--=--module--+---------------+------------------------------------------------------------+   
   |                     '-,--SEQ--=--nn-'                                                            |   
   +-,--OPTION--=--+-+-name-----------+----------------------------------+----------------------------+   
   |               | |    .-,----.    |                                  |                            |   
   |               | |    V      |    |                                  |                            |   
   |               | '-(----name-+--)-'                                  |                            |   
   |               +-DMP-------------------------------------------------+                            |   
   |               +-INS-------------------------------------------------+                            |   
   |               |      .-,--J--=--ALL---.                             |                            |   
   |               +-SNP--+----------------+-----------------------------+                            |   
   |               |      '-,--J--=--jobno-'                             |                            |   
   |               |                       .-,--J--=--ALL---.            |                            |   
   |               +-(--SNP--=--+-name--)--+----------------+----------+-+                            |   
   |               |            |          '-,--J--=--jobno-'          | |                            |   
   |               |            '-JCT--)--+--------------------------+-' |                            |   
   |               |                      |               .-JCTSTG-. |   |                            |   
   |               |                      '-,--SOURCE--=--+-ALL----+-'   |                            |   
   |               |                                      '-JCTDS--'     |                            |   
   |               '-(--SNP--=----OSE--)--+---------+--------------------'                            |   
   |                                      '-,--DIAG-'                                                 |   
   +-,--PATCH-----------------------------------------------------------------------------------------+   
   +-,--PTRAP-----------------------------------------------------------------------------------------+   
   +-,--REGSON----------------------------------------------------------------------------------------+   
   +-,--REGSOFF---------------------------------------------------------------------------------------+   
   +-,--SPADDR--=--mmmm.rrrrrrrr----------------------------------------------------------------------+   
   +-,--TRAP--=--adr--,--START--=--+-*--+---------------------------------------+-------------------+-+   
   |                               |    |             .-0---------------------. |                   | |   
   |                               |    '-,--BASE--=--+-adr-------------------+-'                   | |   
   |                               |                  '-module--+-----------+-'                     | |   
   |                               |                            '-,SEQ=--nn-'                       | |   
   |                               +-adr--,--END--=--adr--+---------------------------------------+-+ |   
   |                               |                      |             .-0---------------------. | | |   
   |                               |                      '-,--BASE--=--+-adr-------------------+-' | |   
   |                               |                                    '-module--+-----------+-'   | |   
   |                               |                                              '-,SEQ=--nn-'     | |   
   |                               '-Rz--,--B--=--nn------------------------------------------------' |   
   +-,--TRAPGO----------------------------------------------------------------------------------------+   
   +-,--TRAPOFF---------------------------------------------------------------------------------------+   
   +-,--TRAPON----------------------------------------------------------------------------------------+   
   '-,--TREGS-----------------------------------------------------------------------------------------'   

>--+-------------------------------------+---------------------><
   '-,--OUT--=--+-devname--------------+-'   
                +-+---+--devnum--------+     
                | '-/-'                |     
                +-(--type--)-----------+     
                +-(--type--,--group--)-+     
                +-(--,--group--)-------+     
                '-+-----+--------------'     
                  '-CON-'

Parameters

ACTIVE

Displays all the active traps in your installation.

C=adr

The starting address of the alteration, or the displacement to be added to BASE.

S=hhh

One to eight pairs of hexadecimal characters to be stored at the specified location. All leading and trailing zeros must be given.

B=nn

The number (in hexadecimal) of bytes to be displayed. This value is rounded up to a multiple of X'10'. The default is X'20' (decimal 32).

BASE=

Specifies the base address. The TRAP, START, and END addresses are displacements to be added to the BASE address. The address can either be specified as a hex address or a module name. The default value is zero.

FIND=module

Requests the entry point address and base of the named module.

SEQ=nn

The nth module on a load list of identically named modules.

Note: An entry point of zero means the module was once loaded but is no longer in storage.

OPTION=(name ,name1 ,...)

The name of dump contents of storage option(s) to be displayed. The format for most control blocks that are dumped by the *S,DC,OPTION= command is shown in z/OS JES3 Diagnosis.

Name:		Displays:
C/I		C/I-related control blocks.
CSA		Tables in the JES3 storage management queue (JES3 uses the IATXSQE macro to add tables to this queue).
DFC		Device fence-related control blocks.
DJC		Dependent job control tables.
DSP		DSP dictionary entries.
DSP=	dspname	A specific DSP dictionary entry.
DYN		The DYN table, the DYQ entries, and their associated ECFs.
ENQ		AENQ-related control blocks.
FCT		The function control table and the auxiliary task dispatching element (ATDE) associated with each function control table entry if one exists.
(FCT=	`{dspname}\| {devname}\| {ddd }\| {dddd }\| {/ddd }\| {/dddd })`	A specific function control table entry and its associated auxiliary task dispatching element (ATDE) if one exists.
FSS		The functional subsystem (FSS) table and all associated functional subsystem application (FSA) tables.
(FSS=fssname)		A specific functional subsystem (FSS) table entry and its FSA tables, if any.
GMS		Generalized main scheduling tables.
GST		Generalized subtast-related control blocks.
ICP		The Initialization Checkpoint Record (ICP).
ITX		The intermediate text records that were created when the initialization stream was read.
ITX=	fileid	A specific intermediate text file.
JIO		Spool I/O control blocks.
JQE		JES3 job queue elements.
JTV		Spool I/O addresses and constants in the TVT.
LOC		Locate-related control blocks.
MDS		Main device scheduler tables.
MEM		JES3 storage (a map is produced).
MOD		Module information from the JDEs
MPC		Main processor control tables.
(MPC=name)		A specific main processor control table entry.
MVD		The Multi-Version Data Access control areas.
NJE		The NJE resident node table and any active line data areas.
(NJE=nodename)		A specific NJE resident table entry and the line data areas if the line is active.
NUC		A map of the JES3 nucleus.
PRT		The printer resources table, pending page queues and pending data set queues.
(PRT=	`{devname}\| {ddd }\| {dddd }\| {/ddd }\| {/dddd }\| {group })`	A specific printer resources table entry, a pending page queue, a pending data set queue, and associated output service control blocks.
RJP		Remote job processing tables.
(RJP=devname)		A specific remote job processing device control table.
RSQ		All the currently active resources.
(RSQ=jobno)		A specific RESQUEUE table entry.
SCT		SYSOUT class tables.
SDA		The Statistics Data Area (SDA).
SRS		MDSSRS-related control blocks.
STN		The SETNAMES table.
(STN=name)		A specific SETNAMES table entry.
STT		Display a summary of the records in the Single Track Table (STT). If a record is not valid, the first 80 hex bytes of the record are displayed.
(STT=ALL)		Display the contents of all records in the STT.
(STT=nnnn)		Display "nnnn" hex bytes of each of the records in the STT.
(STT='id')		Display those STT records that have the specified control block id. When the contents of an STT record is displayed, only the non- zero portion at the end of the record is displayed. For example, if you specify STT=100 to display 100 bytes of each STT record but a particular record contains only 50 bytes, then only 50 bytes of the record will be displayed.
STU		The SETUNITS table.
(STU=	`{ddd }\| {dddd }\| {/ddd }\| {/dddd })`	A specific SETUNITS table entry.
SUP		The SUPUNITS table.
(SUP=	`{devname}\| {ddd }\| {dddd }\| {/ddd }\| {/dddd }\| {group })`	A specific SUPUNITS table entry.
SYS		The SYSUNITS table.
(SYS=	`{ddd }\| {dddd }\| {/ddd }\| {/dddd })`	A specific SYSUNITS table entry.
TRC		The format of the JES3 trace table.
VLM		SETVOL and SETDSN tables.
(VLM=	volser\| GDGBASE)	For volser, a specific SETVOL table entry and associated SETDSN entries are displayed. For GDGBASE, the SETDSN table entries for GDG bases are displayed.
WLM		Workload Manager-related control blocks.
WSB		SNA workstation control blocks.
(WSB=devname)		A specific SNA workstation control block.

DMP

Causes all the standard formatting to be performed just as though a completely formatted JES3 dump was requested without system intervention.

INS

Displays information about internal reader control blocks.

SNP

Causes a dump of job-related control blocks to be recorded on the output device.

(SNP=name)

Causes a dump of a specific job-related control block to be recorded on the output device. You can request any one of the following control blocks:

Name

Dumps the

ARL

Allocation resource list

ASR

Available spool records

JDAB

Job description accounting block

JDS

Job data set control block

RQ

Resqueue

FRP

Format parameter buffer

JST

Job summary table

JVT

Job volume table

TAT

Job or data set track allocation table

MOSE

Master output service element

OSE

Output service element

DIAG

Displays a formatted OSE, which includes such information as:

class
forms
queue
destination

Note: Use caution when specifying this parameter. Control block displays are potentially very long, and output directed to the operator's console can disrupt normal operator/system interaction.

J=jobno or ALL

The number of the job whose control blocks are to be dumped. The default (ALL) causes all jobs’ control blocks to be dumped (that is, the JES3 job queue is dumped). You can use this parameter to select a job number only when the OPTION= parameter is set to SNP or (SNP=name).

JCT

If you specify a dump of the JCT, use the SOURCE= parameter to specify whether dump core should obtain a copy of the JCT from:

The JCT data space
The JCT data set
Both the JCT data space and the data set

See the SOURCE= parameter for any additional coding considerations.

SOURCE=JCTSTG, JCTDS, or ALL

Identifies where you want dump core to obtain a copy of the specified job's JCT from. You can only specify this parameter if you specify OPTION=(SNP=JCT) on the *START,DC command.

JCTSTG: Indicates you want the job's JCT copy that is in storage. This is the default when SOURCE= is not specified.
JCTDS: Indicates you want the job's JCT obtained from the JCT data set.
ALL: Indicates you want the job's JCT copy that is in storage and obtained from the JCT data set. You will get two versions of the requested JCT.

PATCH

Displays the dynamic patch area within module IATUTDC.

PTRAP

Causes all snapshot output from traps to be sent to output service for printing.

REGSON

Causes the registers to be recorded with snapshot data (specified when preparing traps) when a trap is entered.

REGSOFF

Causes the recording of the registers to be disabled when a trap is entered.

SPADDR=mmmm.rrrrrrrr

Displays the contents of the spool record that has a spool address of mmmm.rrrrrrrr. The mmmm portion of the spool address is the spool extent number (module) where the record resides. The rrrrrrrr portion of the spool address is the spool record number within the spool extent. The spool address must be coded exactly as shown; leading zeros in either part of the spool address must be specified.

When the contents of the spool record are displayed, only the non-zero portion at the end of the record is displayed. For example, if a particular spool record contains only zeros after the first 100 bytes of the records, only the first 100 bytes of the record will be displayed.

TRAP=

The address of the location to be intercepted (trapped) during processing. The trap must be at least eight bytes away from any other trap. When the trap is processed, register 12 is assumed to contain the address of the TVT. Register 14 is used by the trap routine, and its original contents are not saved. After the snapshot, the saved instructions are processed, and control is returned to the next user instruction beyond the trap location.

START=*

Causes the FCT active at the time of the trap to be placed in a waiting status so that other DC commands can be used to display or alter storage. Only one trap of this form (START=*) can be active at any given time.

START=adr,END=adr

Specifies the starting and ending addresses of the area to be displayed.

START=Rz,B=nn

Specifies the register number (z) that contains the starting address; the register number must be prefixed by R as shown. In B=nn, nn specifies the length of the area to be displayed.

TRAPGO

Causes the waiting FCT to be posted. Processing resumes with the saved user instructions from the trap location followed by processing of the instruction following the trap.

TRAPOFF

Turns off the snapshot or waiting for all traps.

TRAPON

Turns on the snapshot or waiting for all traps.

TREGS

Causes the registers to be displayed on the console when a waiting trap is entered.

OUT=

Specifies the device which is to receive output from DC. You can use this parameter to direct output to a device other than the one specified on the *CALL,DC command. Specify the device as follows:

devnum or /devnum

The address of the device. The device number can be a 3-digit or 4-digit hexadecimal number. A slash (/) preceding the device number is not required. Device numbers can be specified by any of the following formats:

ddd
dddd
/ddd
/dddd

where ddd and dddd represent the device numbers.

devname

The name of the device as defined by the JNAME keyword of a DEVICE initialization statement.

type

Specifies the type of printer. If you specify PRT, JES3 uses any available printer. Otherwise, specify PRT1403, PRT3211, PRT3203, PRT3800, or PRT3820.

group

The name assigned to a group of devices (typically in physical proximity) and defined by the DGROUP keyword of a DEVICE initialization statement.

CON

Specifies that output is to be directed to the calling console.

Rules

Do not display a fetch-protected storage address on the *S,DC,C= command. Specifying fetch protected storage results in an abnormal end of the DSP. Seez/OS MVS Diagnosis: Reference for additional information about fetch-protected storage areas.

Following a hot start of JES3 without an IPL of MVS™, DC issues message IAT7932 to indicate the modules that were loaded by the MVS LOAD or NIP (link pack area modules) during a previous IPL of MVS. However, these modules still reside in the same storage location.

Do not set traps in modules which run under the DC DSP. Setting traps in these modules can cause abnormal ends and loss of the DSP. These modules are IATUTCB, IATUTDC, IATUTC2, IATUTDA, IATUTD0, IATUTD1, IATUTD2, and all IATABxx series modules.
Do not set traps in modules which reside in LPA, MLPA, or protected storage. Setting traps in these areas results in a protection exception (X'0C4').
Do not set traps in code that runs in 24-bit addressing mode or code that calls other code that runs in 24-bit addressing mode. Setting traps in code which runs in 24-bit addressing mode can result in abnormal ends and failure of the DSP. You can determine the addressing mode of a module by referring to the block comments within the module's code.
Note: This restriction applies only to the addressing mode of a module not to its residency.
Setting a trap that replaces a conditional branch instruction can affect the condition code setting. Unpredictable results can occur when the branch instruction is processed.
Multiple traps in different DSPs or single traps in reentrant DSPs can cause abends and loss of the DSP because IATUTDC trap code is not reentrant and the contents of return registers can be lost.
Do not put traps in the CONSERV and CONCMD DSPs. A trap in these DSP routines will cause the system to fail because these routines are needed to display the trapped information. These modules are IATCNSV, IATCNCN, IATCNRN, IATCNCM, IATCNIN, IATCNIA, IATUX18, and IATCNDQ.
Do not set any traps in code running under the auxiliary task (IATAUX); they will be ignored.
No more than five waiting traps can be active.
You can set traps only on four-byte instructions.

Examples

Set a trap at location X'21E9878' and uses the address in register ten as the address of where to start recording storage. B=10 indicates ten bytes of storage will be displayed:

*START,DC,OUT=CON,TRAP=21E9878,START=R10,B=10

IAT7921  ISSUE START/CANCEL/RESTART DC REQUEST

Dump Core Command:

Display all the traps that are currently active in your system:

*S,DC,ACTIVE

System Response:

IAT7922 THE FOLLOWING IS THE ACTIVE TRAPS
IAT7923 02236D7C-021005B8 00000000 40000000 000000
IAT7923 02236D8C-47F0F024 58E0B188 07FE0000 000000
IAT7923 02236D9C-021005B8 0000000F 80000000 000000
IAT7923 02236DAC-45E0C854 58E0B188 07FE0000 000000
*IAT7921 ISSUE START/CANCEL/RESTART DC REQUEST

Dump Core Command:

*S,DC,BASE=21005B8,TRAP=24,START=R15,B=30

System Response:

*IAT7921 ISSUE START/CANCEL/RESTART DC REQUEST

Dump Core Command:

*S DC OUT=CON,KEY=SYSTEM

System Response:

IAT6306 JOB 0025 IS DC      , CALLED BY CN0C0

*IAT7921 ISSUE START/CANCEL/RESTART DC REQUEST
*START,DC,TRAPON

IAT7921   ISSUE START/CANCEL/RESTART DC REQUEST

Message IAT7921 is issued to indicate DC is ready to process another command.

Dump Core Command:

*S,DC,SPADDR=0003.00000384

System Response:

SPOOL RECORD:  0003.00000384
00000000-00030000  03840000  C3E2C240  00000000 *.....D..CSB ....*
00000010-00000000  00000000  5CA2A3A3  0012D6E4 *........*stt..OU*
00000020-E37EC3D6  D540D2C5  E87EE2E8  E2E3C5D4 *T=CON KEY=SYSTEM*

Dump Core Command:

*S,DC,SPADDR=0002.000012A8

System Response:

SPOOL RECORD:  0002.000012A8
00000000-00020000  12A80001  D6E2C540  00000000 *.....y..OSE ....*
00000010-00000000  00000000  5CA2A3A3  00600060 *........*stt.-.-*
00000020-00000000  00000000  00000000  00000000 *................*
00000030-00000000  00000000  00000000  00000000 *................*
00000040-00000000  00000000  00000000  00000000 *................*
00000050-00000000  00000000  00000000  00000000 *................*
00000060-FFFFFFFF                               *....            *