SUBSYS DD Parameter › Special Considerations When Using SUBSYS › JCL Restrictions

JCL Restrictions

When the addname subparameter is not used, CA Compress dynamically allocates the data set, but when addname is used, the data set is allocated to the associated ddname before CA Compress begins to process it. Minor differences arise, for instance, in processing the DISP parameter and in when the data set is cataloged. A number of incompatibilities exist between the SUBSYS parameter and other JCL parameters. SMS-controlled data sets must be allocated through an associated ddname. In general, many problems can be solved by using the associated ddname facility. Some specific considerations follow:

• Depending on your IBM maintenance level, if you use the SUBSYS parameter with a VSAM cluster, an 0C4 abend is likely when clearing a field in a missing DEB extension (APAR OW10331). IBM is unwilling to fix this problem, and there is no work around.
• AMP=(...)—This is a VSAM-only parameter. If this parameter is specified on a subsystem DD statement, the subsystem routines do not execute properly and abends result.
• DISP=(...,PASS)—Because CA Compress dynamically allocates the data set, PASS is not allowed on the DD statement where SUBSYS is coded. However, PASS can be coded on an associated DD statement which is specified using the CA Compress subsystem 'addname' parameter.
• LABEL=(...,NL,...)—When compressing with SUBSYS with output to a nonlabeled (NL) tape, an associated DD statement must be supplied in order to specify the DCB attributes of the compressed file. An associated DD statement is specified using the CA Compress subsystem 'addname' parameter. Failure to do this results in a S013-34 abend.
• VOL=REF=*.ddname (where ddname is a subsystem DD statement)—The CA Compress subsystem is not able to update the volume list in the subsystem DD entry, so the volume serial remains the same throughout the life of the job.
• SPACE=(...,...,RLSE)—When an application program closes multiple data sets in a single CLOSE macro call where one or more of the data sets is compressed by CA Compress RLSE can cause an S50D abend. CA Compress issues messages ZSUR007I and ZSUR050I.

  BLKSIZE=0—System Determined Blocksize does not work correctly with SUBSYS, because the proper device type is not recognized for SUBSYS data sets. If you use the associated ddname and code BLKSIZE=0 on both ddnames, the BLKSIZE is computed differently in each case, and an abend is likely.