With z/OS, block sizes greater than 32760 bytes can be used for tape data sets. A larger tape block size can improve elapsed time and tape utilization. The larger block sizes allow the tape device to perform better because of the decreased need to start and stop reading blocks. DFSORT's SDB=LARGE or SDB=INPUT option allows DFSORT to select a block size greater than 32760 for a tape output data set. However, you must insure that subsequent applications that use such data sets can handle larger block sizes.