IMS Migration Considerations - IMS UG Oct 2017 Omaha

IMS Migration

Considerations

Migration Considerations

2

IMS V15 Announcement (GA - Oct. 27,2017)

http://www-01.ibm.com/common/ssi/ShowDoc.wss?docURL=/common/ssi/rep_ca/8/897/ENUS217-

398/index.html&lang=en&request_locale=en

Verify software and hardware requisites

–Program Directory

Migration/Coexistence maintenance

–REPORT MISSINGFIX (FIXCAT)

IBM.Coexistence.IMS.V15|IBM.Coexistence.IMS.V14

–PSP Bucket

Review IMS Release Planning guide for this release and any release being skipped

Review PSP Buckets (UPGRADE: IMS1400 | IMS1500)

Install new version of IMS

Possible upgrade to IMS tools and related products

– See - http://www-01.ibm.com/support/docview.wss?uid=swg22009341

Install z/OS interface modules

–IMS Type 2 and Type 4 SVCs

Migration Tasks

3

Perform any D/B recoveries that have Extended Error Queue Elements (EEQE's)

/DIS DB EEQE

Upgrade RECONs

– CHANGE.RECON UPGRADE CHECKUP

System definition (ALL)

ACBGEN

Possible changes to procedures or jobs – Ensure DRA Client address spaces (CICS,DB2 SPAS,

etc.) point to correct SDFSRESL (DRA and JCL)

Re-assemble any user code that accesses IMS control blocks or log records

– Re-work USERMODS as necessary (don’t forget about DFSIDEF0)

Ensure appropriate Dynamic Allocation members and exits are available to the new environment

– Compare members in current SDFSRESL to those in new SDFSRESL

Migration Tasks - 2

4

Monitor changes in storage utilization (CSA/ECSA/PRIVATE/EPRIVATE)

– May need to adjust IMS pool sizes

– Take SVC dumps of IMS address spaces prior to migration and keep them

for comparison purposes

Prepare and test a fallback plan

Cold start (/NRE CHKPT 0 FORMAT ALL)

Migration Tasks - 3

5

Recommend initial migration be done without implementing optional new functions

– Once stable in production then take advantage of new functions

Migration Overview

– Similar tasks as previous IMS release-to-release migrations

• Application programs continue to work without any change or recompile

– Databases do not have to be changed, upgraded, reorganized, image copied, etc.

– Log records have been modified and added

• Products which read logs may need to be updated

• User written programs may need to be modified

• ILOGREC macro may be assembled to map DSECTs for most IMS log records

ILOGREC RECID=ALL

Migration Considerations

6

All distribution libraries (ADFS…) and target libraries (SDFS…) except SDFSRESL may be either a

PDS or PDSE

– Delivered as PDSEs

− SDFSRESL must be a PDS

− Service for UI42189 will require ADFSLOAD be a PDSE

– Other execution data sets, such as FORMAT, ACBLIB, DBDLIB, PSBLIB and MODBLKS must

still be a PDS

In IMS V14 all ++SRC and ++MAC members have been re-sequenced

– Will need to re-work USERMODs

Migration Considerations - V14

7

IMS Logger uses DFSMS Media Manager for WADS

– The WADS dataset must be a VSAM Linear dataset

• CISIZE for WADS must be 4K

• See IVP for sample definition

– Media Manager also uses zHPF (System z High Performance FICON) when available,

which increases IMS throughput

– The systems programmer can optionally request that the Logger use zHyperWrite for

writing to the WADS and/or OLDS (PI75575 adds this support for OLDS)

• ZHYPERWRITE=(WADS=YES,OLDS=YES) IN <LOGGER> section of DFSDFxxx

Must be extended format dataset for OLDS – if not just doesn’t use zHyperWrite

Extended format not required for WADS

Migration Considerations V15 - Logger

8

Consolidation of IMS Logger Parameters

– Logger parms previously in DFSVSMxx moved to new LOGGER section of DFSDFxxx

• WADSDEF

• OLDSDEF

• LOGEDIT

• ARCHDEF

If specified in DFSVSMxx they are ignored

– DFSPBxxx for control region MUST now contain DFSDF parameter

• ARC and WADS parms moved from DFSPBxxx to DFSDFxxx

If specified in DFSPBxxx they are ignored

– DFSDFxxx must contain the new LOGGER section

• ARC

• ARCHDEF

• LOGEDIT

• OLDSDEF

• WADSDEF

• ZHIPERWRITE

Migration Considerations V15 - Logger -2

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IMS Catalog with IMS managed ACBs

− May not need to rebuild directories

• With IMS V14 service for PI82331 and IMS V15 service for PI79314

• See documentation for restrictions

If ACBLIB will be used will need to run V15 ACBGEN

The following is from the announcement:

− IBM intends to require IMS management of ACBs in the future. IMS and the IMS catalog

must be set up to support ACB management

Migration Considerations V15 – Database

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IMS OPTIONS Dataset

– IMS.OPTIONS dataset is obsolete

• Contained only member DFSVTAM

Previously used conditional assemblies in SYSGEN STAGE2

DFSVTAM macro not used in any conditional assemblies

– Sample installations jobs that reference IMS.OPTIONS updated

• DFSALOC1 - allocate target and distribution libraries

• DFSDDEF1 – define SMP/E DDDEFS

Migration Considerations V15, SYSGEN Reduction -

IMS.OPTIONS

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BUFPOOLS macro removed from STAGE1 SYSGEN

– All parms on the BUFPOOL macro can be specified during online startup

• DFSPBxxx or startup JCL

– If specified in SYSGEN

• 2,G116 BUFPOOLS MACRO IS NOT SUPPORTED

SYSGEN is successful


BUFPOOLS Macro

BUFPOOLS

keyword

Default (V14) DFSPBxxx keyword or JCL

override

Default (V15) Description

DMB= 10000 bytes

Rounded up to 12288

(12K)

DMB= 12288 (12K)

bytes

Size of the DMB control block pool.

EPCB= 8192 (8K) bytes EPCB= 8192 (8K) bytes Size of the EPCB pool.

FORMAT= 20% of the PSB

specification.

FBP= 20480 (20K)

bytes

Size of the message format buffer pool.

FRE= See note (1). FRE= 30 Number of fetch request elements (FREs) for loading MFS control

blocks into the message format buffer pool.

PSB= 10000 bytes

Rounded up to 12288

(12K)

PSB= 12288 (12K)

bytes

Size of the PSB control block pool in subpool 231 storage if the

DL/I address space option is not used.

PSBW= 10,000 bytes

Rounded up to 12288

(12K)

PSBW= 12288 (12K)

bytes

Size of the PSB work area pool.

SASPSB=(size1,) 2000 bytes

Rounded up to 4096

(4K)

CSAPSB= 4096 (4K) bytes Size of the PSB control block pool in the z/OS common storage

area (CSA) if the DL/I address space option (LSO=S) is used.

SASPSB=(,size2) 8000 bytes

Rounded up to 8192

(8K)

DLIPSB= 8192 (8K) bytes Size of the PSB control block pool in the DL/I address space if the

DL/I address space option (LSO=S) is used.

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All sample IMS PROCs are provided during SMP/E processing

– Most (not all) of the sample PROCs previously created by SYSGEN created in new

SDFSPROC/ADFSPROC libraries

– New sample installation job DFSPROCB creates PROCs in IMS.PROCLIB

• Creates remaining ‘PROCLIB’ members

Existing sample IMS PROCS (such as the CSL task PROCs) that were already provided outside of

SYSGEN, processing is unchanged

IMSGEN PROCLIB=keyword is ignored

– Message G918 is issued with MNOTE,2 if specified

– SYSGEN is successful

Most parts in SDFSPROC have same name


Sample Procedures

ACBGEN

DBBBATCH

DBC

DCC

DFSBMP

DFSIFP

DFSJBP

DFSJMP

DFSMPR

DFSPBDBC

DFSPBDBC

DFSPBDCC

DFSPBIMS

DFSUOLC

DFSVSM00

DLIBATCH

FDR

FPUTIL

IMS

IMSCOBGO

IMSCOBOL

IMSDALOC

IMSFP

IMSJBP

IMSJMP

IMSMSG

IMSMSV

IMSPLI

IMSPLIGO

INITMOD

MFSBACK

MFSBTCH1

MFSBTCH2

MFSDCT

MFSREST

MFSRVC

MFSTEST

MFSUTL

OLCUTL

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Some SDFSPROC parts have different names than the original PROC names

– Part names already existed in IMS and cannot be reused

– Some procedure names could be overridden by SYSGEN macro options

– Some procedures do not have replacement parts via SMP/E processing

• CBLTDLI, DFSACBCP, DFSMREC, FMTCOPY, PLITDLI, REFCPY

Packaging rules require copyright statements in each part

These are input statements, adding copyright causes utility failure


Sample Procedures (2)

– PROCLIB Member Name New V15 Part Name

– DBDGEN DFSDBDGN

– PSBGEN DFSPSBGN

– IMSBATCH DFSIMSBT

PROCLIB Member Name New V15 Part Name

DBRC or from IMSCTRL DBRCNM= DBRC

DLISAS or from IMSCTRL DLINM= DLISAS

IMSRDR or from IMSCTF PRDR= IMSRDR

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New DFSPROCB sample JCL built by SMP/E processing

– Intended as a post SMP/E processing job that results in all parts in the SDFSPROC library named the same as they were in prior IMS releases in IMS.PROCLIB

• Creates sample parts in SDFSPROC

DFSACBCP

CBLTDLI

DFSMREC

FMTCPY

PLITDLI

REFCPY

• Renames sample procedures in SDFSPROC to original PROC name

DFSDBDGN to DBDGEN

DFSIMSBT to IMSBATCH

DFSPSBGN to PSBGEN

– The Installation Instructions section of the Program Directory refers to DFSPROCB

Copy these sample procedures into IMS.PROCLIB

– See IVP for sample

Hint: Compare PARMS in your current IMS procedures with PARMS in the V15 provided procedures and

incorporate V15 changes in your existing procedures as needed

Backup charts contain details relating to individual procedures


Sample Procedures (3)

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User Exits Loaded Standalone

−User Exits are no longer in the NUCLEUS

−User Exits are loaded as stand-alone during IMS initialization or restart

−The interface for the exits is not being changed

−User Exits may run “above the line” -> below the line PVT VSCR

−DFSME000 and DFSME127 are shipped as AMODE 31 and RMODE ANY

−User Exits are NOT eligible for dynamic REFRESH

−Customer Action Required:

Move COMM macro specifications to DFSPBxxx parameters

FESEXIT=, FESTIM=, MFSEXITF=, MFSEXITS=, SIMEXIT=, USERMSGS=

Link user exits

Ensure that user exits do not reference the NUCLEUS (VCONs)

Link DFSCSI00 with the user exit if callable services are required


User Exits

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Migration Considerations V15, SYSGEN Reduction -User Exits (2)

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IMS Stage 1

Macro Definitions

User exit loaded standalone

during IMS initialization

Load DFSCNTE0

USERMSGS=Y Load DFSCMTU0

TYPE or LINEGRP macroEDIT=(name1)

Load DFSCTTO0and user-defined

SIMEXIT=YES Load DFSSIML0

MFSEXITF=(000-fld)MFSEXITS=(seg-127)

Load DFSME000-127

FESEXIT=YFESTIM=timeout

Load DFSFEBJ0

TYPE or LINEGRP macroEDIT=(,name2)

Load DFSPIXT0and user-defined

TRANSACT macroEDIT=(name)

Load DFSCSMB0and user-defined

DFSPBxxx

Definitions

NAME macroEDIT=YES

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The IMSGEN USERLIB= parameter is ignored in IMS15

The COMM FESEXIT=, MFSEXIT=, OPTIONS=USERMSGS and SIMEXIT= parameters

are ignored

−Remove COMM macro keyword parameters no longer supported:

FESEXIT

MFSEXIT

OPTIONS=USERMSGS

SIMEXIT

−Remove USERLIB keyword in the IMSGEN macro

−Migrate stage 1 COMM options to PROCLIB members

−Make sure the user exits in USERLIB are accessible to IMS STEPLIB and APF authorized

Backup charts contain details relating to individual exits


User Exits (3)

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IMSCTF macro removed from STAGE1 SYSGEN (PI83450/UI50511 – not in GA base)

− If specified

• MNOTE 2,’G122 IMSCTF MACRO IS NOT SUPPORTED.’

• SYGEN still successful

− CPLOG – Checkpoint log frequency

• Specify CPLOG= in the DFSPBxxx PROCLIB member or JCL override

− LOG – DD statements to be provided in SYSGEN built PROCs

• PROCS no longer created by SYSGEN

Default PROCs have DDs commented out

LOG=SNGL|DUAL (IEFRDER2)

MONITOR (IMSMON)

− PRDR – Name of PROC to be used for /STA REG commands

• Specify PRDR= in the DFSPBxxx PROCLIB member or JCL override

− RDS – Restart dataset buffer size

• Specify RDS= in the DFSPBxxx PROCLIM member or JCL override

Migration Considerations V15, SYSGEN Reduction -IMSCTF macro

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− SVCNO – Type 2 and type 4 SVC IMS SVC numbers

• User to assemble and link edit module DFSIDEF0 to provide SVC numbers

DFSIDEF0 CSECT

DFSIDEF TYPE=BEGIN

DFSIDEF TYPE=PARM,DBRC=YES

DFSIDEF TYPE=PARM,SVC2=203

DFSIDEF TYPE=PARM,SVC4=202

DFSIDEF TYPE=END

END DFSIDEF0

• If module DFSIDEF0 not present defaults used (T2 – 254, T4 – 255)

• As always, need to link edit SVCs into z/OS

– Use DFSIDEF0 with TYPE=GEN to create sample JCL which can be used to LINK EDIT SVC’s into SDFSRESL

Sample JCL goes to SYSPRINT DD

DFSIDEF0 CSECT

DFSIDEF TYPE=GEN,SVC2=203

DFSIDEF TYPE=GEN,SVC4=202

END DFSIDEF0

• Link into SYS1.NUCLEUS (T2) and SYS1.LPALIB/MLPALIB (T4) from SDFSRESL or ADFSLOAD

• Run SMP/E JCLIN

• See IVP job/tasks IV_C302J, IV_D209T, IV_D210T

Migration Considerations V15, SYSGEN Reduction -IMSCTF macro (2)

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License Acceptance panels removed from IMS V15 VUEs

All ++SRC and ++MAC members have been re-sequenced

• Will need to re-work USERMODs

Migration Considerations V15 – Misc.

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CQS (Shared Queues)

− IMS V15 cannot register with a pre IMS V15 CQS

− IMS V14 cannot register with a pre IMS V14 CQS

− IMS V13 or IMS V14 can register with an IMS V15 CQS

− User or vendor written CQS clients that want to register with IMS V15 CQS must use

CQS macros from IMS V13, IMS V14 or IMS V15

− User or vendor written CQS clients that are assembled with IMS V15 CQS macros

cannot register with a PRE IMS V15 CQS

− A V13, V14 or V15 CQS can connect to the same coupling facility

CSL

− If running a mixed version IMSplex recommend CSL address spaces use the latest

version of IMS (SCI, OM, RM)

• ODBM version must match IMS version

Data Sharing

− IMS databases may be shared between supported IMS releases

Coexistence

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Database Recovery Utilities

− IMS V15 Database Recovery utility (DFSURDB0) and Database

Change Accumulation utility (DFSUCUM0)

• Accepts logs, Image Copy and Change Accumulation datasets from

IMS V13 or later

Utility inputs

− Batch Backout, Log Archive, Log Recovery, Log Analysis

•Use utility from IMS release which produced the log

IMS V15 RECONs may be used by all supported IMS releases

− With compatibility service

Extended checkpoints

− Cannot be used to restart applications across different IMS versions

See Release Planning Guide for additional considerations

Coexistence - Cont

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A system may fallback to a previous release after upgrade

− Upgraded RECONs are used

− Additional considerations:

• Database recoveries use latest IMS version utilities

• Always use ACBLIB built at the level of the running system

• Cold start (/NRE CHKPT 0 FORMAT ALL)

Fallback

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The following SVC's are used by IMS

− T2 DFSVC200 (IGCxxx)

• Downward compatible. Can use the one from the highest level of IMS with previous

versions

• SVC number specified in SYSGEN or default of 254 used (V14)

• SVC number specified in DFSIDEF0 or default of 254 used (V15)

DFSPBxxx member

• Can be updated dynamically for life of the IPL using DFSUSVC0

− T4 DSP00MVS (IGC00xxx)

• Downward compatible. Can use the one from the highest level of IMS with previous

versions

• SVC number specified in SYSGEN or default of 255 used (V14)

• SVC number specified in DFSIDEF0 or default of 255 used (V15)

• Can be updated dynamically for life of the IPL using DFSUSVC0

− Create an SMP/E USERMOD for DFSIDEF0

• Example in PSP bucket

IMS SVCs

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IMS Utility DFSUSVC0 can be used to update both the IMS T2 and IMS T4 SVC

dynamically

− Lasts for the life of the IPL

• Loads SVC in CSA/ECSA and updates z/OS SVCTABLE to point to new module

• T2 SVC processing

Checks IMS SVC directory table to determine if any IMS tasks/jobs currently

running and if so request to update T2 SVC fails

• T4 SVC processing

Load a new copy in ECSA each time DFSUSVC0 run requesting T4 SVC to be

updated

• The following shows an example of the JCL which for executing DFSUSVC0:

//STEP1 EXEC PGM=DFSUSVC0,PARM='SVCTYPE=(2,4)'

//*STEP1 EXEC PGM=DFSUSVC0,PARM='SVCTYPE=(2)'

//*STEP1 EXEC PGM=DFSUSVC0,PARM='SVCTYPE=(4)'

//STEPLIB DD DSN=IMS.SDFSRESL,DISP=SHR

//DFSRESLB DD DSN=IMS.SDFSRESL,DISP=SHR

//SYSPRINT DD SYSOUT=*

DFSUSVC0

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Contact the IMS Level 2 for assistance

−We are here to help and your success is our reason for being

Migration/Installation Assistance

IMS Migration

Considerations -

Backup Data

Backup Data

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Variable Data

− Symbolic parameters added to PROCs for keywords which were previously part of SYSGEN definition and generation

− Sample procedures use IMS defaults and can be updated

− IVP modified to use symbolic parms in JCL


Sample Procedures (B1)

Procedure parameter Default value Description

CSSLIB ‘SYS1.CSSLIB’ This is a new parameter. Specifies the name of the z/OS callable services library

data set, which corresponds to the CSSLIB parameter of the IMSGEN macro.

IMSID ‘IMSA’ This is an existing parameter. Specifies the identifier for the IMS control region,

which corresponds to the IMSID parameter of the IMSCTRL macro.

MACSYS ‘SYS1.MACLIB’ This is a new parameter. Specifies the name for the MACLIB data set to be used in

stage 2 assemblies, which corresponds to the MACSYS parameter of the IMSGEN

macro.

NODE1 ‘IMS’ This is a new parameter. Specifies the high-level qualifier of the IMS data sets,

which corresponds to the first node name specified in the NODE parameter of the

IMSGEN macro.


which corresponds to the second node name specified in the NODE parm of the

IMSGEN macro.


which corresponds to the third node name specified in the NODE parameter of the

IMSGEN macro.

OLCPLEX ‘IMSPLEX’ This is a new parameter. Specifies the data set qualifier (or qualifiers) for the

OLCSTAT data set, which corresponds to the IMSPLEX parameter of the IMSGEN

macro.

SCEERUN ‘CEE.SCEERUN’ This is a new parameter. Specifies the name of the System C Runtime Library data

set, which corresponds to the SCEERUN parameter of the IMSGEN macro.

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DFSWTxxx and IMSWTxxx Considerations

− In IMS 14, these PROCs were generated as multiple parts (000, 001,…) each corresponding to a LINEGRP UNITYPE=SPOOL definition in STAGE1

Procedure would include JCL DD statements for each SPOOL name

– In IMS 15, new parts DFSWT000 and IMSWT000 are a single set with sample SPOOL definitions

Procedures must be modified by System Programmer to specify actual SPOOL definitions needed by the installation

Additional procedures can be created for each additional LINEGRP

IMS and DCC Considerations

− In IMS 14, these PROCs will contain DD statements for the following device types, corresponding to LINEGRP definitions and MSPLINK/CTC definitions

DISK, MSC channel-to-channel, PRINTER, PUNCH, READER, SPOOL, and TAPE

− In IMS 15, new parts IMS and DCC contain sample definitions

Procedures must be modified by System Programmer to code DD statements based on actual device types used by the installation



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Conditional Statement Generation

− New sample procedures assume a ‘standard’ DB/DC system

• IMS environment is not known (DBCTL, DCCTL, XRF, etc…)

− ‘Non-standard’ environments have conditionally generated statements commented out

• Prolog in each sample procedure instructs how procedure should be modified

• PROCs with conditional statements for non-standard environments:

BATCH – the system is BATCH – IMSCTRL SYSTEM=(BATCH)

DBCTL – the system is DBCTL – IMSCTRL SYSTEM=(DBCTL)

DCCTL – the system is DCCTL – IMSCTRL SYSTEM=(DCCTL)

DUAL - dual data sets for the system log are required – IMSCTF LOG=(DUAL)

MFSTEST - MFSTEST included

COMM OPTIONS=MFSTEST or IMSGEN MFSTEST=YES

MONITOR - Monitor data set for logging is required – IMSCTF LOG=(MONITOR)

XRF – the system is XRF, IMSCTRL HSB=YES



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DFSCMTU0 - User Message Table

− Loaded during IMS Initialization only if USERMSGS=Y in DFSPBxxx/JCL

If DFSCMTU0 is not loaded:

DFS1934E issued

IMS proceeds as if USERMSGS=N were specified

DFS060 issued for invalid message key if user messages are referenced

Restart required to reload the exit

DFSCNTE0 – CNT Destination Edit Routine

− Called only for static terminals

Not applicable to dynamic terminals

NAME EDIT=(YES) required in System Definition

Same as it was in V14, no change required

No equivalent specification in DFSPBxxx/JCL

− Loaded during IMS Initialization only if at least 1 static terminal LTERM defined EDIT=(YES)

If DFSCNTE0 is not loaded:

DFS1934E issued

DFS4861W issued for each static terminal with EDIT=(YES) defined

IMS proceeds as if EDIT=NO was specified for the LTERM

No destination edit routine is called for messages queued to the destination LTERM



User Exits (B1)

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User Exits (B2)

DFSCSMB0 (and user-defined) – Transaction Input Edit Routine

− IMS-provided sample routine is DFSCSMB0

− User-supplied exits can be any name

There can be many – each transaction could define a different exit routine

− Statically-defined transactions

TRANSACT EDIT=(YES) required in System Definition


Exits loaded during IMS initialization

DFS3398E issued, and transaction stopped, if exit could not be loaded

Similar to error processing during import from the Repository


− Dynamically-created transactions

Processing is the same as it was in V14

CREATE/UPDATE TRAN/TRANDESC command with EDITRTN() specified

Exits loaded during command processing if not already loaded

Command is rejected if exit could not be loaded

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User Exits (B3)

DFSCTTO0 and DFSPIXT0 (and user-defined) – Physical Terminal Output/Input Edit

Routines

− IMS-provided sample routines are DFSCTTO0 (output) and DFSPIXT0 (input)

− User-supplied exits can be any name

There can be many – each terminal could define a different exit routine

− Statically-defined terminals

TYPE|LINEGRP EDIT=(output,input) and TERMINAL EDIT=(YES,YES) required in System Definition

TYPE for VTAM, LINEGRP for non-VTAM


Exits loaded during IMS initialization

If exit is not loaded

DFS1934E issued

DFS4862W (VTAM) or DFS4863W (non-VTAM) issued for each terminal with EDIT=(YES) defined

IMS proceeds as if EDIT=NO was specified for the terminal

No output/input edit routine is called for terminal messages


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User Exits (B4)

DFSCTTO0 and DFSPIXT0 (and user-defined) – Physical Terminal Output/Input Edit

Routines…

− Dynamically-created terminals (ETO)

• Processing is the same as it was in V14

• Node descriptor with EDIT=(output,input) required

• Exits loaded during descriptor creation during IMS initialization

DFSFEBJ0 – Front End Switch Routine

− OPTIONS=FES required

• Static terminals - TERMINAL macro in System Definition

• Dynamic terminals – Logon descriptor

• Same as it was in V14, no change required

− Loaded during IMS Initialization only if FESEXIT=Y in DFSPBxxx/JCL

• If DFSFEBJ0 is not loaded:

DFS1934E issued

DFS4864W issued for each terminal with OPTIONS=FES specified

IMS proceeds as if OPTIONS=NOFES (default) was specified

No FES routing occurs


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User Exits (B5)

DFSSIML0 – Shared Printer Message Router Routine

− Called only for static printers

• Not applicable to dynamic terminals

• TERMINAL OPTIONS=SHARE required in System Definition


− Loaded during IMS initialization if SIMEXIT=Y in DFSPBxxx/JCL

• If DFSSIML0 is not loaded:

DFS1934E issued

IMS proceeds as if SIMEXIT=N was specified

Printer processing continues as if OPTIONS=NOSHARE was specified


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User Exits (B6)

DFSME000-DFSME127 – MFS Input Message Field and Segment Edit Routines

− Loaded during IMS initialization based on MFSEXITF= and MFSEXITS= in DFSPBxxx/JCL

• MFSEXITF=xxx determines the range (DFSME000-DFSMExxx) of Message Field exits

DFSME000 is always loaded

• MFSEXITS=yyy determines the range (DFSMEyyy-DFSME127) of Segment exits

DFSME127 is always loaded

• If DFSMExxx is not loaded:

DFS1934E issued

IMS proceeds without the user exit

MFS processing continues as if MFSEXIT had not specified the exit number


IMS Migration Considerations - IMS UG Oct 2017 Omaha

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