JCL Considerations

Identifies a sequential output data set, normally SYSOUT, that contains the IDCAMS SYSPRINT from IAM’s invocation of IDCAMS to define a Linear Data Set to hold an IAM Pervasively Encrypted file. IAM will dynamically allocate this file, if IAM Global Options are set to do so. An IAM user can also add this DD statement to their IAM File Define for an encrypted data set.

When specified as a DD DUMMY, will result in IAM issuing a U0184 ABEND for various error conditions. This is done to provide a simple mechanism to obtain a dump for problem diagnosis. This DD statement will also cause various IAM error messages to appear, which normally would not appear because of commonly encountered error conditions that are typically handled by return codes.

The IAMDEBUG DD statement should only be used when requested by IAMTechnical Support. Using it otherwise may result in normally running jobs abending unexpectedly.

An optional DD card, that when specified, will be used for dumping the IAM index data space when an IAM file is being closed under a task that is abending. This will normally be a SYSOUT data set.

Identifies a sequential output data set, which is normally SYSOUT. IAM will set the required DCB characteristics for this data set, so specification of a DCB is not recommended. IAM produces the IAMINFO reports with a RECFM=FBA and an LRECL=121. This data set will contain a report that is produced by IAM, every time an IAM file is closed. The report contains file description information, along with statistics on file usage and resource requirements to process the data set. Use of this feature is highly recommended, and may be requested by IAM Technical Support for problem resolution, particularly for performance related questions. These IAMINFO reports can also be generated by the IAMSMF utility program provided the installation is collecting and saving the optional IAM SMF records.

When specified as a DD DUMMY on job steps that perform an IDCAMS LISTCAT request, the DD card will prevent the production of the IAMPRINT reports for IAM files. This is primarily intended for use when a job is doing a LISTCAT of an entire catalog, and it is desirable to eliminate the overhead of IAM processing, which can be significant when thousands of data sets are being processed.

Specifies a card image data set, which contains the control cards and keywords to use or modify the use of various IAM features. This is normally a DD * (SYSIN type) of data set, however, it can also be a sequential data set, or a member of a partitioned data set. Refer to the section on IAM Overrides for complete information on using this facility.

Identifies a sequential output data set, normally SYSOUT, that contains a report on IAM file characteristics whenever a LISTCAT ALL is done for an IAM file. IAM will normally dynamically allocate this file to the default SYSOUT class (SYSOUT=*). For TSO users, the output is automatically routed to the user's terminal. The DD card can be optionally provided by the user, to capture the output to a data set, or route the output to a different SYSOUT class. The user need not provide any DCB information, however, they should be aware that the file will have an LRECL=121 and a RECFM=FBA.

An optional DD statement that provides a temporary data set to be used during an IAM file load to hold the index. Normally, IAM will default to using a Data Space of up to 2048 megabytes that is adequate for all except the extremely large data set. For example data sets that are using 1/4 track for a block size, with a 64 byte key, the data space is sufficient for up to 102 gigabytes of compressed data. To force the use of the work file, the CREATE Override DATASPACE=0 must be specified. No DCB characteristics should be specified, and adequate space must be allocated.

When specified within a job step, indicates that IAM will not flag dynamically allocated IAM data sets as DSORG=VS in the JFCB for the data set. This is intended for use when running data set management utility software, such as CA-DISK and CA-DMS.