Controlling the IMS PROCLIB data set

Carefully examine the procedures generated during SMP/E processing.

Although many of the procedures generated in the IMS.SDFSPROC data set require alteration before they can be used in direct execution of the online system, they do provide a convenient start to the task of defining execution JCL. Many of the members have content that directly indicates the options you specified in the system definition stage 1 input.

You should carefully examine the procedures generated during SMP/E processing.

Renaming the IMS PROCLIB data set members

Rename the IMS PROCLIB data set members according to your installation's requirements. The names can follow a convention that suggests ownership by a particular application system or a convention that has an implied sequence. For example:

IMSIMAG: Initial procedure for image copies of database
IMSCTL: Control region startup (IMS renamed)
IMSTXLD: BMP to preload a transaction queue (IMSBATCH)
IMSMSG1: Message region startup (IMSMSG)
IMSBCH1: Low-priority BMP (IMSBATCH)
IMSMSG2: Second message region when required (IMSMSG)
IMSWT000: Spool output print procedure (named by IMS)

The system operator or master terminal operator (MTO) uses the procedure names to start the job on z/OS®.

To develop these members, you need to either rename the members in the IMS PROCLIB data set or create new members. In some installations, the procedures are added to SYS1.PROCLIB. One option of the NODE keyword on the IMSGEN macro allows you to substitute an alternative library naming convention, so that your base PROCLIB data set can be named LEGAL.PROCLIB.

Altering members of your PROCLIB data set

You must alter the JCL content of the members of the PROCLIB data set. The updates you apply follow naming conventions for your IMS systems and the required DD statements.

Table 1 summarizes the ways you can tailor the PROCLIB data set member, excluding arrangements for batch executions. In all procedures, you might want to add JCL comment statements for additional documentation. Your PROCLIB data set might not contain all the members listed below.

Table 1. Tailoring actions for PROCLIB data set members for batch executions
PROCLIB data set member	Tailoring action
IMS	Checks and overrides the EXEC PARM parameter. Specifies region size again. Moves to SYS1.PROCLIB. Adds database DD statements, if not dynamically allocated. Specifies logging data sets again; allows for dynamic allocation.
IMSRDR	Adjusts all symbolic parameters for message region start by system operator. Moves to SYS1.PROCLIB.
DBC	Checks and overrides EXEC PARM parameter. Specifies region size again. Moves to SYS1.PROCLIB. Adds database DD statements, if not dynamically allocated. Specifies logging data sets again, allow for dynamic allocation.
DBRC	Adds RECON DD statements, if not dynamically allocated. Renames the procedure, if desired, and specifies this name with the DBRCNM parameter of the IMS procedure. Adjusts procedures JCLOUT and JCLPDS. Moves to SYS1.PROCLIB.
DFSDCxxx	Specifies data communication options.
DFSFDRxx	Defines the IMSID tracked by the active FDBR. Defines whether FDBR applies to DEDB areas defined as SHARELVL=0\|1. Defines z/OS cross-system coupling facility group name for the active IMS system and the FDBR tracking region. Specifies the number of seconds before FDBR goes into timeout status. Specifies whether control blocks for DEDB processing are allocated in private storage or ECSA.
DLISAS	Adds full-function database DD statements and removes the corresponding statements from the IMS procedure. (No changes are necessary for dynamically allocated databases). Specifies sizes of two PSB pools using the DLIPSB and CSAPB parameters of the IMS procedure. Moves the pools to SYS1.PROCLIB. If the procedure is renamed, specifies this name with the DLINM parameter of the IMS procedure.
IMSMSG	Adjusts JOB statement parameters for DFSMPR execution. Moves to IMS.JOBS
DFSMPR	Checks and specifies EXEC PARM parameters.
IMSBATCH	Checks and specifies EXEC PARM parameters. Add z/OS DD statements.
DFSVSMxx	Defines buffer pools and other options. Allows use of sequential buffering. Specifies initial WADS and OLDS and dual logging. Coordinates with IMS procedure. Enables long busy handling.
DFSHSBxx	Establishes IMS active and alternate subsystems in XRF complex.
DFSDRFxx	Defines DREF requirements list.
DFSFIXxx	Defines page fix list.
DFSINTxx	Defines, loads, and executes user-written exits during dependent region initialization.
DFSMPLxx	Defines preload program list.
DFSSQxxx	Defines PROCLIB data set member for CQS address space. Defines subsystem name for CQS address space. Defines name for shared expedited message handler queues. Defines primary structure containing shared message queues. Defines XCF IMS shared queues group name.
IMSWTnnn	Adjusts JOB statement parameters for DFSWTnnn execution. Moves to IMS.JOBS.
DFSWTnnn	Checks and specifies SYSOUT class for spooled output.
DXRJPROC	Establishes procedures for each required IRLM address space.
DFSPBIMS	Renames to DFSPBxxx, where xxx is determined by IMS procedure RGSUF=xxx. Defines IMS control region execution parameters.
DFSPBDBC	Renames to DFSPBxxx, where xxx is determined by DBC procedure RGSUF=xxx. Defines DBC control region execution parameters.
DFSPBDCC	Renames to DFSPBxxx, where xxx is determined by DCC procedure RGSUF=xxx Defines DCC control region execution parameters.

Preparing for IMS job execution

In preparation for executing the IMS procedure as a system task, the members IMS, IMSRDR, DBC, DCC, DBRC, and DLISAS are moved to SYS1.PROCLIB. Additional members of the IMS PROCLIB data set, especially IMSMSG and the set of IMSWTnnn members for spool output, need to be tailored to satisfy your installation's requirements. IMSMSG invokes the procedure DFSMPR, and the IMSWTnnn members invoke DFSWTnnn. To enable message region and spool output jobs to be started with IMS commands or from the system console, these members, after tailoring, are moved to the IMS.JOBS data set, which is concatenated with SYS1.PROCLIB.

Preparing IMS PROCLIB data set member DFSPBxxx

IMS PROCLIB data set member DFSPBxxx contains IMS control region execution parameters. However, the values specified on the EXEC statement override (but do not nullify) any parameters specified in DFSPBxxx. To build or update a DFSPBxxx member, use the IMS Syntax Checker.

IMS also creates sample DFSPBxxx members during system definition. The sample members are as follows:

DFSPBIMS for IMS DB/DC
DFSPBDBC for DBCTL
DFSPBDCC for DCCTL

These samples contain all the valid parameters for the specified IMS control region. To use the DFSPBxxx member, code RGSUF=xxx on the invocation of the IMS procedure.

Tailoring Fast Path execution procedures in DB⁄DC or DCCTL

As a result of defining Fast Path application programs in system definition macros, the contents of the IMS PROCLIB data set include two procedures for executing Fast Path dependent regions in a DB/DC or DCCTL environment:

IMSFP: To execute a region containing a Fast Path application program
FPUTIL: To execute online DEDB utilities

You must tailor both of these procedures to the requirements of individual programs. Also, several of the other members of the IMS PROCLIB data set have EXEC statement parameters that specifically apply to Fast Path or need to reflect Fast Path requirements. The additional tailoring actions are summarized in the table below.

Table 2. Tailoring actions for Fast Path procedures
IMS PROCLIB data set member	Tailoring action
IMS	Specify buffering and output thread limits Respecify region size. Add appropriate DEDB DD statements. Allocate MSDB initialization data set.
DFSMPR	Specify buffering reserved for this region.
IMSBATCH	Specify buffering reserved for this region.
IMSFP	Specify the application program and region size. Specify buffering reserved for this region.
FPUTIL	Specify the DEDB name and restart indicator. Provide the utility control statements.
DFSFIXxx	Page fix list for Fast Path control blocks.
DBFMSDBx	List of MSDBs and segments to be loaded.

Tailoring Fast Path execution procedures in DBCTL

After defining Fast Path application programs in system definition macros, the contents of the IMS PROCLIB data set in a DBCTL environment include FPUTIL, a procedure that executes online DEDB utilities.

This procedure must be tailored to the requirements of individual programs. Also, several of the other members of the IMS PROCLIB data set have EXEC statement parameters that specifically apply to Fast Path or need to reflect Fast Path requirements. The additional tailoring actions are summarized in the table below.

Table 3. Tailoring actions for Fast Path procedures in a DBCTL environment
IMS PROCLIB data set member	Tailoring action
DBC	Specify buffering and output thread limits Respecify region size Add appropriate DEDB DD statements
IMSBATCH	Specify buffering reserved for this region
FPUTIL	Specify the DEDB name and restart indicator Provide the utility control statements
DFSFIXxx	Page fix list for Fast Path control blocks

Controlling modifications to the IMS PROCLIB data set

Using operator commands keeps the initial operating instructions simple and avoids complex symbolic parameter data entry. However, you must control the exact content of the JCL residing in the IMS PROCLIB data set. For example, the master terminal operator enters:

/START REGION IMSBCH1

The procedure IMSBCH1 must be correctly coordinated to a known BMP, appropriate PSB and transaction queue, other system options, and identifying parameters.

Your control responsibilities can include auxiliary procedures for database reorganization, recovery, or system output control. Further, the modification level of each procedure must be coordinated to the actual production environment. For example, if an application program is modified and requires more dependent region storage, you must coordinate the program library and IMS PROCLIB data set changes. One technique is to include JCL comment statements that document the date and the reason for the change.

Take special care to check that the physical changes you make in IMS PROCLIB data set members. Many of the DD statements extend over several input records and involve positional parameters, so you need to make more than a cursory examination of a change. You can use a data dictionary to record and maintain the IMS PROCLIB data set members. Changes can then be checked at the terminal or by reviewing listings of the changed members.