dick scherrer wrote:... DF/DSS and HSM provide far better performance. Especially if the data to be copied is large.
Back in the mid-eighties I wrote code the beat the s... out of the DF/DSS of that era. It was just regular QSAM copy, too, but it was done in multiple tasks, which was why it was faster than DF/DSS running in one task. The data sets were mostly small, too; the big cost was allocation and OPEN/CLOSE that didn't have the benefit of indexed VTOC, though that dragged down both DF/DSS and my program.