PARMDD parameter usage in an IDMS CV

Products

• IDMS

Issue/Introduction

IDMS allows users to specify numerous run-time options for a Central Version (CV) via the PARM= parameter on the jobstep's EXEC card. These options are documented at Specifying Runtime Options. However, in the z/OS environment, the operating system limits the total length of the values passed through the PARM= parameter to 100 bytes. The CV options can be abbreviated but some users may still run into the 100 character limitation.

Starting with Release 2.1 of z/OS, IBM has provided a new parameter, PARMDD=, which can be used in place of the PARM= parameter.  PARMDD= specifies the DDNAME of a file within the CV's start-up JCL that will contain those options previously supplied using PARM=.  A string length of up to 32760 characters is allowed by z/OS but currently IDMS limits the total length of the string passed to 256 characters. Details of the use of the PARMDD= parameter can be found in z/OS MVS JCL Reference.

Environment

Release: All supported releases.

Resolution

The coding of the options within the file specified on the PARMDD= parameter is rather forgiving in terms of format. The following two examples provide alternate formats for the coding of the IDMS CV options. The first example codes each option on a separate record within the file starting in column 1. In both examples a record length of 80 was used to define the PARMDD file.

SYSTEM=700,
DMCLNAM=R190DMCL,
RRS=N,
MT=N,
ZIIP=Y,
WTOEXIT=WTOEXIT,
SUBTASKS=3,
MTQDEPTH=2,
STEPLIB=Y,
PROMPT=NO,
RMAPSIZE=30,
FREESTG=1600

Within the startup JCL, it is necessary to include the PARMDD= parameter on the EXEC card, and later within the JCL, the specified DDNAME must be included as in the following example.

//IDMSCV   EXEC PGM=RHDCOMVS,REGION=0M,TIME=1440,PARMDD=PARMS
...
//PARMS    DD DSN=<idms.parms>,DISP=SHR

To be able to utilize the PARMDD= parameter, it is necessary for module RHDCOMVS to be relinked using the LONGPARM=YES command. This parameter is only valid for z/OS 2.1 and later releases. The following example provides the BINDER statements that should be used to relink RHDCOMVS. Each statement starts in column 2.

 INCLUDE LOADMOD(RHDCOMVS)
 ENTRY   STARTUP
 ALIAS   IDMSDC
 ALIAS   IDMSCV
 SETOPT PARM(LONGPARM=YES,REUS=NONE)
 SETCODE AC(1)
 NAME RHDCOMVS(R)

LOADMOD points to the load library containing your the RHDCOMVS module.

An attempt to execute a CV that contains the PARMDD= parameter on the EXEC statement without RHDCOMVS properly linked with the LONGPARM=YES parameter will result in an ABEND306-44 error.