Non-VSAM preallocation

An existing data set qualifies as a preallocated target for a data set copy operation if the data set names match, the complete data set is available on target volumes, and:

For single-volume target qualification, the data set organization is partitioned or the data set’s volume sequence number in the VTOC is 1 and the last volume flag is on.
For multivolume target or single-volume target with the last volume flag off, the data set is cataloged in the standard order of search. All volume serial numbers returned by a locate operation on the data set are in the output volume list. (Candidate volumes are acceptable.)

Note: If a target data set is preallocated, but is not large enough to contain the source data set, it will be scratched and reallocated if it is being renamed.

You may use data set COPY to upgrade your standard format sequential data sets to large format data sets. When copying a data set and a usable preallocated target is found, it will be used as the target of the copy operation. When copying a standard format sequential data set and a preallocated large format data set is found, it will be used. If the preallocated large format data set does not have enough space for the source data, it will be scratched and reallocated as a large format data set. When copying a large format data set and a standard format sequential data set is found, it will be used and upgraded to a large format data set. If the preallocated standard format sequential data set does not have a large enough allocation to hold the source data, it will be scratched and reallocated as a large format data set.

If a user wishes to downgrade a large format data set to a standard format sequential data set, allocate a standard format sequential data set and use a utility such as IEBCOPY to copy the data from the large format data set to the standard format sequential data set.

You may also use data set COPY to upgrade your data sets that are not enabled for CA reclaim to data sets that are enabled for CA reclaim. To do this, simply preallocate a data set that is enabled for CA reclaim to use as a target of the copy. In copying a data set that is not enabled for CA reclaim, if a preallocated data set that is enabled for CA reclaim is found, the preallocated data set that is enabled for CA reclaim is used for the target of the copy. If the preallocated data set that is enabled for CA reclaim is not large enough to hold the data being copied, it is scratched and reallocated as a data set that is enabled for CA reclaim. In copying a data set that is enabled for CA reclaim, if a preallocated data set that is not enabled for CA reclaim is found, the data set that is not enabled for CA reclaim is used for the target of the copy. If the preallocated data set that is not enabled for CA reclaim is not large enough to hold the data being copied, it is scratched and reallocated as a data set that is not enabled for CA reclaim.

Start of change For PDSEs, the source data set’s original version level is preserved after the copy or move, regardless of the version level of the pre-allocated target data set. For example, if the pre-allocated target data set is a PDSE with version level 2, and the source data set is a PDSE with version level 1, after a copy or move the target would be a PDSE with level 1. End of change

The preallocated data set is usable if all of the following conditions that apply to the data set being processed are met:

The user is authorized to update the target data set.
The DSORG matches.
For direct access data sets, the target does not exist if the copy operation is done using the IEHMOVE utility. If the RELBLOCKADDRESS keyword is specified for the data set, preallocated targets are allowed.
For unmovable data sets, extents match exactly when you copy to a like device without specifying the FORCE keyword.
For movable data sets or unmovable data sets with the FORCE keyword, the amount of allocated space in the target data set is greater than or equal to the amount of allocated space in the source data set.
For partitioned data sets, the target directory can contain all source members and aliases.
For preallocated standard user label data sets, the target has more than one extent when the source data set has more than one extent.

If a VSAM or non-VSAM preallocated data set is determined to be unusable, message ADR439E is issued, and the copy operation is stopped only for that data set. No attempt is made to clear or alter the target data set if:

The source data set is empty.
The DSORG is not supported.
The target is preallocated but not empty.

Message ADR363E is issued to inform the user.